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Marion TL, Bradshaw WT. Congenital central hypoventilation syndrome and the PHOX2B gene mutation. Neonatal Netw 2012; 30:397-401. [PMID: 22052119 DOI: 10.1891/0730-0832.30.6.397] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) is a rare syndrome of dysfunction of the autonomic nervous system characterized by a decreased response to hypercarbia. It is a disorder in which affected individuals fail to breathe during sleep despite progressive hypercapnia and hypoxia. Infants simply fall asleep and quit breathing. They are found by their parents or caregivers blue and lifeless. CCHS is an autosomal dominant disease. It has been linked with tumors of neural crest origin, segmental aganglionosis of the colon, and diffuse autonomic dysregulation but can occur alone. Discovery of the genetic link between the paired-like homeobox 2B (PHOX2B) genetic mutations and CCHS represents a breakthrough in the diagnosis of CCHS, association of mutated alleles with disease severity, and clues to the pathophysiology responsible for the disorder. Early genetic screening and intervention can provide the families of these infants with hope for achieving a normal life.
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Affiliation(s)
- Tara L Marion
- Brenner Children’s Hospital, Wake Forest Baptist Health.
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Abstract
INTRODUCTION Patients with congenital central hypoventilation syndrome (CCHS) show brain injury in areas that control chemosensory, autonomic, motor, cognitive, and emotion functions, which are deficient in the condition. Many of these abnormal characteristics are present from the neonatal period; however, it is unclear whether tissue injury underlying the characteristics progressively worsens with time. We hypothesized that several brain areas in subjects with CCHS would show increased gray matter volume loss over time. METHODS We collected high-resolution T1-weighted images twice (4 years apart) from seven subjects with CCHS (age at first study, 16.1 ± 2.7 years; four males) and three control subjects (15.9 ± 2.1 years; three males) using a 3.0-Tesla magnetic resonance imaging (MRI) scanner, and evaluated regional gray matter volume changes with voxel-based morphometry (VBM) procedures. RESULTS Multiple brain sites in CCHS, including frontal, prefrontal, insular, and cingulate cortices; caudate nuclei and putamen; ventral temporal and parietal cortices; and cerebellar cortices showed significantly reduced gray matter volume over time. Only limited brain areas, including sensory, temporal, and medullary regions, emerged with increased gray matter at the later age. DISCUSSION Patients with CCHS show reduced gray matter volume with age progression in autonomic, respiratory, and cognitive regulatory areas, an outcome that may contribute to deterioration of functions found in the syndrome with increasing age.
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Marsh K, Ehrhardt E. Case reports of congenital central hypoventilation syndrome. Neonatal Netw 2012; 31:157-161. [PMID: 22564311 DOI: 10.1891/0730-0832.31.3.157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Congenital central hypoventilation syndrome (CCHS), which occurs in less than 1 in every 50,000 infants and children, is a rare syndrome first noted in literature by Mellins in 1970. Congenital central hypoventilation syndrome is a condition in which the patient loses the drive to breathe during deep sleep and can mimic many diseases. Until recently, CCHS has largely been a diagnosis of exclusion; fortunately, there is now a genetic test available to confirm the diagnosis. The purpose of this article is to discuss the steps taken to confirm the diagnosis of CCHS. In addition to the history of the disease and clinical manifestations, genetics and prognosis of children with CCHS will be discussed. Two cases are presented for illustration of hospital course and preparation for discharge.
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Affiliation(s)
- Kim Marsh
- Childrens Hospital and Medical Center, 8200 Dodge St., Omaha, NE 68114, USA.
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Pupillometry in congenital central hypoventilation syndrome (CCHS): quantitative evidence of autonomic nervous system dysregulation. Pediatr Res 2012; 71:280-5. [PMID: 22278185 DOI: 10.1038/pr.2011.38] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Congenital central hypoventilation syndrome (CCHS) is characterized by alveolar hypoventilation, autonomic nervous system (ANS) dysregulation (ANSD), and mutations in the paired-like homeobox 2B (PHOX2B) gene. ANSD in CCHS affects multiple systems and includes ophthalmologic abnormalities. We hypothesized that quantitative pupil measures, obtained using pupillometry, would vary between cases with CCHS and controls and within those with CCHS by PHOX2B genotype. RESULTS Measures known to be illustrative of sympathetic and parasympathetic response (prestimulus, maximum pupil diameter, percentage of pupil constriction after light stimulus, and average constriction and dilation velocities) were significantly reduced in those with CCHS as compared with controls (all P < 0.05). DISCUSSION These reductions are indicative of both sympathetic and parasympathetic deficits in CCHS, which is in keeping with the role of PHOX2B in ANS development. An inverse linear relationship was apparent in pupil diameter and velocity measurements among the cases with CCHS with the most common heterozygous PHOX2B polyalanine expansion repeat mutations, suggesting a graded phenotype/genotype dose response based on polyalanine repeat length. These results confirm our central hypotheses while offering the first objective measures of pupillary dysfunction and ophthalmologic-specific ANSD in CCHS. METHODS A total of 316 monocular measurements were taken under dark-adapted conditions with a fixed light stimulus from 22 PHOX2B mutation-confirmed cases with CCHS and 68 healthy controls.
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Denjean A. Une histoire de gènes respiratoires. Rev Mal Respir 2012; 29:374-5. [DOI: 10.1016/j.rmr.2012.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 01/07/2012] [Indexed: 11/27/2022]
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Jennings LJ, Yu M, Rand CM, Kravis N, Berry-Kravis EM, Patwari PP, Weese-Mayer DE. Variable human phenotype associated with novel deletions of the PHOX2B gene. Pediatr Pulmonol 2012; 47:153-61. [PMID: 21830319 DOI: 10.1002/ppul.21527] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 06/16/2011] [Indexed: 11/07/2022]
Abstract
BACKGROUND Clinical testing for PHOX2B mutations is widely used for patients with any symptoms suggestive of hypoventilation (with/without anatomic/physiologic autonomic dysregulation), though not necessarily with the congenital central hypoventilation syndrome (CCHS) phenotype. Consequently, a multitude of referrals for clinical PHOX2B testing (fragment analysis of the 20 polyalanine repeat region and/or sequencing of entire coding region) have no identifiable mutation. Whole gene deletions/duplications have recently been identified as a common disease-causing mechanism, but have not been reported in a clinical population referred for PHOX2B testing. The objective of this study was to determine if PHOX2B exon or whole gene deletion/duplication would be identified in a subset of patients referred for PHOX2B testing. HYPOTHESIS We hypothesized that PHOX2B exon or whole gene deletion or duplication would be identified in a subset of cases who were referred for genetic testing but not found to have a PHOX2B mutation with currently available clinical PHOX2B testing. METHODS Genomic DNA samples from patients that tested negative for PHOX2B mutations using fragment analysis and/or sequencing, and control samples, were screened for PHOX2B exon deletions/duplications by multiplex ligation-dependent probe amplification with confirmation by array comparative genomic hybridization. RESULTS Deletions of/in PHOX2B were identified in 4/250 patients and 0/261 controls. The deletions ranged from 6,216 base pairs (involving only PHOX2B exon 3) to 2.6 megabases (involving all of PHOX2B and 12 other genes). The case with PHOX2B partial exon 3 deletion had a CCHS-compatible phenotype (hypoventilation, Hirschsprung disease). Phenotypes for the other three cases, all PHOX2B whole-gene deletions, were varied including: (1) apparent life threatening event, (2) full CCHS necessitating artificial ventilation with ganglioneuroblastoma, and (3) hypoventilation during sleep. Family studies of two of the four probands showed these deletions to be maternally inherited; the mothers also had phenotypic findings of autonomic dysfunction. CONCLUSIONS PHOX2B exon or whole gene deletion should be considered as another mechanism of disease which may include CCHS, Hirschsprung disease, and/or tumors of neural crest origin, although the genotype-phenotype relationship requires further clarification. Pediatr Pulmonol. 2012; 47:153-161. © 2011 Wiley Periodicals, Inc.
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Affiliation(s)
- Lawrence J Jennings
- Department of Pathology, Children's Memorial Hospital, 2300 Children's Plaza, Chicago, Illinois, USA.
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Domanski MC, Preciado DA. Vocal cord collapse during phrenic nerve-paced respiration in congenital central hypoventilation syndrome. F1000Res 2012; 1:42. [PMID: 24358809 PMCID: PMC3752620 DOI: 10.12688/f1000research.1-42.v1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/20/2012] [Indexed: 11/20/2022] Open
Abstract
Objective: Phrenic nerve pacing can be used to treat congenital central hypoventilation syndrome (CCHS). We report how the lack of normal vocal cord tone during phrenic paced respiration can result in passive vocal cord collapse and produce obstructive symptoms. Methods: We describe a case of passive vocal cord collapse during phrenic nerve paced respiration in a patient with CCHS. As far as we know, this is the first report of this etiology of airway obstruction. The patient, a 7-year-old with CCHS and normal waking vocal cord movement, continued to require nightly continuous positive airway pressure (CPAP) despite successful utilization of phrenic nerve pacers. On direct laryngoscopy, the patient’s larynx was observed while the diaphragmatic pacers were sequentially engaged. Results: No abnormal vocal cord stimulation was witnessed during engaging of either phrenic nerve stimulator. However, the lack of normal inspiratory vocal cord abduction during phrenic nerve-paced respiration resulted in vocal cord collapse and partial obstruction due to passive adduction of the vocal cords through the Bernoulli effect. Bilateral phrenic nerve stimulation resulted in more vocal cord collapse than unilateral stimulation. Conclusions: The lack of vocal cord abduction on inspiration presents a limit to phrenic nerve pacers.
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Affiliation(s)
- Mark C Domanski
- Department of Surgery, University of Mississippi, Jackson, MS, 39216, USA
| | - Diego A Preciado
- Department of Otolaryngology, Children's National Medical Center, Washington, D.C., 20010-2970, USA
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Walusinski O, Kurjak A, Andonotopo W, Azumendi G. Fetal yawning assessed by 3D and 4D sonography. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/14722240500284070] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Congenital central hypoventilation syndrome (CCHS) is a rare, lifelong condition wherein control of breathing is abnormal and patients present with symptoms of alveolar hypoventilation. The severity of hypoventilation varies and although most patients present in the neonatal period, late onset cases have been reported. In 2003, it was discovered that mutations in the PHOX2B gene were responsible for CCHS. This gene also plays a role in neural crest cell migration, and many patients present with symptoms of autonomic dysfunction in addition to hypoventilation. The pathophysiology responsible for hypoventilation remains unclear although a unifying hypothesis is that the abnormality is located in areas of the brain involved in integration of chemoreceptor afferent pathways for ventilation. The goal of treatment for CCHS is to ensure adequate ventilation during wakefulness and sleep. A variety of ventilation modalities are available including positive pressure ventilation via tracheostomy, non-invasive ventilation via nasal mask, and diaphragmatic pacing. With close monitoring and support, children with CCHS can be expected to function well in society and have a good quality of life.
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Affiliation(s)
- F Healy
- Division of Pulmonary Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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60
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Crawford MW. The paired-like homeobox 2B (PHOX2B) gene and respiratory control. Can J Anaesth 2011; 58:1063-8. [PMID: 22006076 DOI: 10.1007/s12630-011-9591-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 09/12/2011] [Indexed: 11/24/2022] Open
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Mahfouz AKM, Rashid M, Khan MS, Reddy P. Late onset congenital central hypoventilation syndrome after exposure to general anesthesia. Can J Anaesth 2011; 58:1105-9. [PMID: 21989548 DOI: 10.1007/s12630-011-9590-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 09/12/2011] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Prolonged postoperative hypoventilation presents a challenge to anesthesiologists with regard to assessing etiology and related treatment. We present a case of recurrent episodes of postoperative hypoventilation in a previously asymptomatic child after uneventful general anesthesia. In this case, the child eventually required lifelong ventilatory support during sleep. CLINICAL FEATURES A case of postoperative hypoventilation in a previously asymptomatic six-year-old child was investigated to determine the possible etiology. After uneventful general anesthesia for dental surgery, the child experienced recurrent episodes of hypoventilation associated with sleep. The child's lungs were mechanically ventilated due to failure of all trials of weaning. Clinical examination was unremarkable and laboratory investigations excluded the possibility of thyroid, hepatic, renal, and neuromuscular diseases. Computerized tomography, magnetic resonance imaging, and electroencephalogram studies were within normal limits. A negative pyridostigmine trial ruled out myasthenia. The child was finally diagnosed as having "late onset congenital central hypoventilation syndrome". Genetic testing revealed a PHOX2B mutation consistent with this diagnosis. The child was discharged home on mechanical ventilatory support during sleep. CONCLUSION Congenital central hypoventilation syndrome is a rare lifelong multisystem disorder which may occur during the neonatal period as a result of severe genetic mutation in the PHOX2B gene. In mild mutations, a triggering factor, such as sedation or anesthesia, may be required for the syndrome to manifest itself. These patients often require lifelong mechanical ventilatory support, particularly during sleep.
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Affiliation(s)
- Abdul Kader M Mahfouz
- Department of Anesthesia, Al Nahda Hospital, PO 937, PC 112 Ruwi, Muscat, Sultanate of Oman.
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Macey PM, Moiyadi AS, Kumar R, Woo MA, Harper RM. Decreased cortical thickness in central hypoventilation syndrome. Cereb Cortex 2011; 22:1728-37. [PMID: 21965438 DOI: 10.1093/cercor/bhr235] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Central hypoventilation syndrome (CHS) is a rare condition characterized by hypoventilation during sleep, reduced ventilatory responsiveness to CO(2) and O(2), impaired perception of air hunger, and autonomic abnormalities. Neural impairments accompany the condition, including structural injury, impaired cerebral autoregulation, and dysfunctional autonomic control. The hypoventilation may induce cortical hypoxic injury, additional to consequences of maldevelopment from PHOX2B mutations present in most CHS subjects. We assessed cortical injury in clinically diagnosed CHS using high-resolution magnetic resonance imaging scans, collected from 14 CHS (mean age ± standard deviation [SD] 17.7 ± 5.0 years; 6 female) and 29 control (mean age ± SD, 17.9 ± 4.3 years; 12 female) subjects. We measured group differences in mean cortical thickness and age-thickness correlations using FreeSurfer software, accounting for age and sex (0.1 false discovery rate). Reduced thickness in CHS appeared in the dorsomedial frontal cortex and anterior cingulate; medial prefrontal, parietal, and posterior cingulate cortices; the insular cortex; anterior and lateral temporal lobes; and mid- and accessory motor strips. Normal age-related cortical thinning in multiple regions did not appear in CHS. The cortical thinning may contribute to CHS cardiovascular and memory deficits and may impair affect and perception of breathlessness. Extensive axonal injury in CHS is paralleled by reduced cortical tissue and absence of normal developmental patterns.
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Affiliation(s)
- Paul M Macey
- School of Nursing, Brain Research Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
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Duty BD, Wozniak SE, Selden NR. Vagal nerve stimulator placement for medically refractory seizures in a child treated with phrenic nerve pacing for congenital central hypoventilation syndrome. J Neurosurg Pediatr 2011; 7:413-5. [PMID: 21456915 DOI: 10.3171/2011.1.peds10520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) is a rare, idiopathic disorder characterized by a failure of automatic respiration. Abnormalities such as seizure disorder, failure to thrive, and Hirschsprung disease have been associated with CCHS. In this report, the authors discuss the use of vagal nerve stimulation (VNS) to treat a medically refractory seizure disorder in a child who had previously undergone placement of bilateral phrenic nerve stimulators for treatment of CCHS. Concomitant use of phrenic and vagal nerve stimulators has not previously been reported in the literature. No adverse reactions were noted with both devices working. Diaphragmatic pacing (DP) was clinically unaffected by VNS. The patient experienced a marked reduction in seizure frequency and severity following vagal nerve stimulator placement. Based on this case, the authors conclude that VNS is a potentially safe and efficacious treatment option for seizure disorder associated with CCHS in patients undergoing DP.
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Affiliation(s)
- Brian D Duty
- Department of Urology, North Shore University Hospital Long Island Jewish Medical Center, Manhasset, New York, USA
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Peeters B, Benninga MA, Hennekam RC. Childhood constipation; an overview of genetic studies and associated syndromes. Best Pract Res Clin Gastroenterol 2011; 25:73-88. [PMID: 21382580 DOI: 10.1016/j.bpg.2010.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 12/03/2010] [Accepted: 12/13/2010] [Indexed: 01/31/2023]
Abstract
Constipation is a common problem in children but little is known about its exact pathophysiology. Environmental, behavioural but also genetic factors are thought to play a role in the aetiology of childhood constipation. We provide an overview of genetic studies performed in constipation. Until now, linkage studies, association studies and direct gene sequencing have failed to identify mutations in specific genes associated with constipation. We show that along with functional constipation, there are numerous clinical syndromes associated with childhood constipation. These syndromic forms of constipation appear to be the result of mutations in genes affecting all aspects of the normal physiology of human defecation. We stress that syndromic causes of childhood constipation should be considered in the evaluation of a constipated child.
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Affiliation(s)
- B Peeters
- Department of Paediatric Gastrointestinal Motility and Nutrition, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands.
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Kumar R, Macey PM, Woo MA, Harper RM. Selectively diminished corpus callosum fibers in congenital central hypoventilation syndrome. Neuroscience 2011; 178:261-9. [PMID: 21256194 DOI: 10.1016/j.neuroscience.2011.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 01/10/2011] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS), a condition associated with mutations in the PHOX2B gene, is characterized by loss of breathing drive during sleep, insensitivity to CO2 and O2, and multiple somatomotor, autonomic, neuropsychological, and ophthalmologic deficits, including impaired intrinsic and extrinsic eye muscle control. Brain structural studies show injury in peri-callosal regions and the corpus callosum (CC), which has the potential to affect functions disturbed in the syndrome; however, the extent of CC injury in CCHS is unclear. Diffusion tensor imaging (DTI)-based fiber tractography procedures display fiber directional information and allow quantification of fiber integrity. We performed DTI in 13 CCHS children (age, 18.2±4.7 years; eight male) and 31 control (17.4±4.9 years; 18 male) subjects using a 3.0-Tesla magnetic resonance imaging scanner; CC fibers were assessed globally and regionally with tractography procedures, and fiber counts and densities compared between groups using analysis-of-covariance (covariates; age and sex). Global CC evaluation showed reduced fiber counts and densities in CCHS over control subjects (CCHS vs. controls; fiber-counts, 4490±854 vs. 5232±777, P<0.001; fiber-density, 10.0±1.5 vs. 10.8±0.9 fibers/mm2, P<0.020), and regional examination revealed that these changes are localized to callosal axons projecting to prefrontal (217±47 vs. 248±32, P<0.005), premotor (201±51 vs. 241±47, P<0.012), parietal (179±64 vs. 238±54, P<0.002), and occipital regions (363±46 vs. 431±82, P<0.004). Corpus callosum fibers in CCHS are compromised in motor, cognitive, speech, and ophthalmologic regulatory areas. The mechanisms of fiber injury are unclear, but may result from hypoxia or perfusion deficits accompanying the syndrome, or from consequences of PHOX2B action.
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Affiliation(s)
- R Kumar
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095-1763, USA
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Kumar R, Macey PM, Woo MA, Harper RM. Rostral brain axonal injury in congenital central hypoventilation syndrome. J Neurosci Res 2010; 88:2146-54. [PMID: 20209631 DOI: 10.1002/jnr.22385] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Brain injury underlying the state-related loss of ventilatory drive, autonomic, cognitive, and affective deficits in congenital central hypoventilation syndrome (CCHS) patients appears throughout the brain, as demonstrated by magnetic resonance (MR) T2 relaxometry and mean diffusivity studies. However, neither MR measure is optimal to describe types of axonal injury essential for assessing neural interactions responsible for CCHS characteristics. To evaluate axonal integrity and partition the nature of tissue damage (axonal vs. myelin injury) in CCHS, we measured water diffusion parallel (axial diffusivity) and perpendicular (radial diffusivity) to rostral brain fibers, indicative of axonal and myelin changes, respectively, with diffusion tensor imaging (DTI). We performed DTI in 12 CCHS (age 18.5 + or - 4.9 years, 7 male) and 30 control (17.7 + or - 4.6 years, 18 male) subjects, using a 3.0-Tesla MR imaging scanner. Axial and radial diffusivity maps were calculated, spatially normalized, smoothed, and compared between groups (analysis of covariance; covariates, age and gender). Significantly increased radial diffusivity, primarily indicative of myelin injury, emerged in fibers of the corona radiata, internal capsule, corpus callosum, hippocampus through the fornix, cingulum bundle, and temporal and parietal lobes. Increased axial diffusivity, suggestive of axonal injury, appeared in fibers of the internal capsule, thalamus, corona radiata, and occipital and temporal lobes. Multiple brain regions showed both higher axial and radial diffusivity, indicative of loss of tissue integrity with a combination of myelin and axonal injury, including basal ganglia, bed nucleus, and limbic, occipital, and temporal areas. The processes underlying injury are unclear, but likely stem from both hypoxic and developmental processes.
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Affiliation(s)
- Rajesh Kumar
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
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Goridis C, Dubreuil V, Thoby-Brisson M, Fortin G, Brunet JF. Phox2b, congenital central hypoventilation syndrome and the control of respiration. Semin Cell Dev Biol 2010; 21:814-22. [DOI: 10.1016/j.semcdb.2010.07.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Accepted: 07/25/2010] [Indexed: 10/19/2022]
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Noninvasive Positive Pressure Ventilation in the Treatment of Hypoventilation in Children. Sleep Med Clin 2010. [DOI: 10.1016/j.jsmc.2010.05.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
A wide variety of mechanisms can lead to the hypoventilation associated with various medical disorders, including derangements in central ventilatory control, mechanical impediments to breathing, and abnormalities in gas exchange leading to increased dead space ventilation. The pathogenesis of hypercapnia in obesity hypoventilation syndrome remains somewhat obscure, although in many patients comorbid obstructive sleep apnea appears to play an important role. Hypoventilation in neurologic or neuromuscular disorders is primarily explained by weakness of respiratory muscles, although some central nervous system diseases may affect control of breathing. In other chest wall disorders, obstructive airways disease, and cystic fibrosis, much of the pathogenesis is explained by mechanical impediments to breathing, but an element of increased dead space ventilation also often occurs. Central alveolar hypoventilation syndrome involves a genetically determined defect in central respiratory control. Treatment in all of these disorders involves coordinated management of the primary disorder (when possible) and, increasingly, the use of noninvasive positive pressure ventilation.
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Affiliation(s)
- Lee K Brown
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, 1101 Medical Arts Avenue NE, Building #2, Albuquerque, NM 87102, USA.
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Kapnadak SG, Mikolaenko I, Enfield K, Gress DR, Nathan BR. Ondine's curse with accompanying trigeminal and glossopharyngeal neuralgia secondary to medullary telangiectasia. Neurocrit Care 2010; 12:395-9. [PMID: 20066515 DOI: 10.1007/s12028-009-9321-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Central hypoventilation syndrome ("Ondine's Curse") is an infrequent disorder that can lead to serious acute or chronic health consequences. This syndrome, especially in adults, is rare, and even less frequent in the absence of clear pathogenic lesions on MRI. In addition, we are not aware of any previously reported cases with associated cranial nerve neuralgias. METHODS We describe a patient with baseline trigeminal and glossopharyngeal neuralgia, admitted with episodes of severe hypoventilatory failure of central origin, consistent with "Ondine's Curse". After evaluation, she was found to have a medullary capillary telangiectasia, thought to be the causative lesion, and which could explain her complete neurologic and hypoventilatory syndrome. The patient was treated with placement of a diaphragmatic pacing system, which has been effective thus far. RESULTS This case illustrates the need for investigation of centrally mediated apnea, especially when co-occurring cranial nerve neuralgia is present and cardiopulmonary evaluation is negative. It provides an example of capillary telangiectasia as the causative lesion, one that to our knowledge has not been reported before. CONCLUSIONS Placement of a diaphragmatic pacing system was warranted and became lifesaving as the patient was deemed to be severely incapacitated by chronic ventilatory insufficiency.
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Montirosso R, Morandi F, D'Aloisio C, Berna A, Provenzi L, Borgatti R. International Classification of Functioning, Disability and Health in children with congenital central hypoventilation syndrome. Disabil Rehabil 2010; 31 Suppl 1:S144-52. [PMID: 19968527 DOI: 10.3109/09638280903317807] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The main aim of this study is to examine the functioning of children with congenital central hypoventilation syndrome (CCHS), a rare disorder of respiratory control associated with physiological and anatomical manifestations of a generalised autonomic nervous system dysfunction, using WHO's International Classification of Functioning, Disability and Health, Children and Youth version (ICF-CY). METHOD The data of 26 children, (F = 17) aged 1.5-17.5 years, were collected. Data were analysed in the following four age groups: <3, 3-6, 7-12 and 13-18 years, using only the ICF-CY questionnaires' cross-age items. RESULTS In the body functions, component breathing and paying attention were common problems for four age groups. In the activity and participation component, all children, except adolescents, showed problems with language. Furthermore, problems in social interaction were evident for all age ranges, except the youngest. Finally, in the environmental factors component, parents reported limitations concerning the natural environment and human-made changes to the environment that were common to all ages. CONCLUSIONS The study supports the usefulness of supplementing diagnostic classifications with functional classifications to obtain complete information on health-related conditions in children with CCHS.
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Affiliation(s)
- Rosario Montirosso
- Department of Child Neuropsychiatry and Neurorehabilitation, IRCCS E. Medea Associazione La Nostra Famiglia, Bosisio Parini, LC, Italy.
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73
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Weese-Mayer DE, Berry-Kravis EM, Ceccherini I, Keens TG, Loghmanee DA, Trang H. An official ATS clinical policy statement: Congenital central hypoventilation syndrome: genetic basis, diagnosis, and management. Am J Respir Crit Care Med 2010; 181:626-44. [PMID: 20208042 DOI: 10.1164/rccm.200807-1069st] [Citation(s) in RCA: 323] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Congenital central hypoventilation syndrome (CCHS) is characterized by alveolar hypoventilation and autonomic dysregulation. PURPOSE (1) To demonstrate the importance of PHOX2B testing in diagnosing and treating patients with CCHS, (2) to summarize recent advances in understanding how mutations in the PHOX2B gene lead to the CCHS phenotype, and (3) to provide an update on recommendations for diagnosis and treatment of patients with CCHS. METHODS Committee members were invited on the basis of their expertise in CCHS and asked to review the current state of the science by independently completing literature searches. Consensus on recommendations was reached by agreement among members of the Committee. RESULTS A review of pertinent literature allowed for the development of a document that summarizes recent advances in understanding CCHS and expert interpretation of the evidence for management of affected patients. CONCLUSIONS A PHOX2B mutation is required to confirm the diagnosis of CCHS. Knowledge of the specific PHOX2B mutation aids in anticipating the CCHS phenotype severity. Parents of patients with CCHS should be tested for PHOX2B mutations. Maintaining a high index of suspicion in cases of unexplained alveolar hypoventilation will likely identify a higher incidence of milder cases of CCHS. Recommended management options aimed toward maximizing safety and optimizing neurocognitive outcome include: (1) biannual then annual in-hospital comprehensive evaluation with (i) physiologic studies during awake and asleep states to assess ventilatory needs during varying levels of activity and concentration, in all stages of sleep, with spontaneous breathing, and with artificial ventilation, and to assess ventilatory responsiveness to physiologic challenges while awake and asleep, (ii) 72-hour Holter monitoring, (iii) echocardiogram, (iv) evaluation of ANS dysregulation across all organ systems affected by the ANS, and (v) formal neurocognitive assessment; (2) barium enema or manometry and/or full thickness rectal biopsy for patients with a history of constipation; and (3) imaging for neural crest tumors in individuals at greatest risk based on PHOX2B mutation.
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74
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Evans KC. Cortico-limbic circuitry and the airways: insights from functional neuroimaging of respiratory afferents and efferents. Biol Psychol 2010; 84:13-25. [PMID: 20211221 PMCID: PMC2908728 DOI: 10.1016/j.biopsycho.2010.02.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 02/01/2010] [Accepted: 02/11/2010] [Indexed: 01/25/2023]
Abstract
After nearly two decades of active research, functional neuroimaging has demonstrated utility in the identification of cortical, limbic, and paralimbic (cortico-limbic) brain regions involved in respiratory control and respiratory perception. Before the recent boon of human neuroimaging studies, the location of the principal components of respiratory-related cortico-limbic circuitry had been unknown and their function had been poorly understood. Emerging neuroimaging evidence in both healthy and patient populations suggests that cognitive and emotional/affective processing within cortico-limbic circuitry modulates respiratory control and respiratory perception. This paper will review functional neuroimaging studies of respiration with a focus on whole brain investigations of sensorimotor pathways that have identified respiratory-related neural circuitry known to overlap emotional/affective cortico-limbic circuitry. To aid the interpretation of present and future findings, the complexities and challenges underlying neuroimaging methodologies will also be reviewed as applied to the study of respiration physiology.
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Affiliation(s)
- Karleyton C Evans
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, 13th Street, Charlestown, MA 02129, USA.
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75
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Goridis C, Brunet JF. Central chemoreception: lessons from mouse and human genetics. Respir Physiol Neurobiol 2010; 173:312-21. [PMID: 20307691 DOI: 10.1016/j.resp.2010.03.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 03/12/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
The response to increased P(CO(2)) in the brain is an essential drive to breathe and required for CO(2) and pH homeostasis in the blood, but where and how CO(2) is sensed are still contentious issues. Here, we review evidence from mouse and human genetics that argue for the crucial role in CO(2) chemosensitivity of a limited set of central neurons that express the Phox2b transcription factor and are disabled by Phox2b mutations. A common trait of different Phox2b mutations that impair CO(2) responsiveness in the embryo and respiration in neonates is the depletion of Phox2b-expressing neurons in the retrotrapezoid nucleus, providing genetic evidence for their importance for proper breathing and central chemosensitivity at birth.
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Affiliation(s)
- Christo Goridis
- Institut de Biologie de l'Ecole normale supérieure (IBENS), Paris, France.
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76
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Ogren JA, Macey PM, Kumar R, Woo MA, Harper RM. Central autonomic regulation in congenital central hypoventilation syndrome. Neuroscience 2010; 167:1249-56. [PMID: 20211704 DOI: 10.1016/j.neuroscience.2010.02.078] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 02/26/2010] [Accepted: 02/28/2010] [Indexed: 10/19/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) patients show significant autonomic dysfunction in addition to the well-described loss of breathing drive during sleep. Some characteristics, for example, syncope, may stem from delayed sympathetic outflow to the vasculature; other symptoms, including profuse sweating, may derive from overall enhanced sympathetic output. The dysregulation suggests significant alterations to autonomic regulatory brain areas. Murine models of the genetic mutations present in the human CCHS condition indicate brainstem autonomic nuclei are targeted; however, the broad range of symptoms suggests more widespread alterations. We used functional magnetic resonance imaging (fMRI) to assess neural response patterns to the Valsalva maneuver, an autonomic challenge eliciting a sequence of sympathetic and parasympathetic actions, in nine CCHS and 25 control subjects. CCHS patients showed diminished and time-lagged heart rate responses to the Valsalva maneuver, and muted fMRI signal responses across multiple brain areas. During the positive pressure phase of the Valsalva maneuver, CCHS responses were muted, but were less so in recovery phases. In rostral structures, including the amygdala and hippocampus, the normal declining patterns were replaced by increasing trends or more modest declines. Earlier onset responses appeared in the hypothalamus, midbrain, raphé pallidus, and left rostral ventrolateral medulla. Phase-lagged responses appeared in cerebellar pyramis and anterior cingulate cortex. The time-distorted and muted central responses to autonomic challenges likely underlie the exaggerated sympathetic action and autonomic dyscontrol in CCHS, impairing cerebral autoregulation, possibly exacerbating neural injury, and enhancing the potential for cardiac arrhythmia.
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Affiliation(s)
- J A Ogren
- UCLA School of Nursing, Los Angeles, CA 90095, USA
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77
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Post-mortem pathologic and genetic studies in “dead in bed syndrome” cases in type 1 diabetes mellitus. Hum Pathol 2010; 41:392-400. [DOI: 10.1016/j.humpath.2009.08.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 08/19/2009] [Accepted: 08/26/2009] [Indexed: 11/24/2022]
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78
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Parodi S, Vollono C, Baglietto MP, Balestri M, Di Duca M, Landri PA, Ceccherini I, Ottonello G, Cilio MR. Congenital central hypoventilation syndrome: genotype-phenotype correlation in parents of affected children carrying a PHOX2B expansion mutation. Clin Genet 2010; 78:289-93. [PMID: 20236122 DOI: 10.1111/j.1399-0004.2010.01383.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Congenital Central Hypoventilation Syndrome (CCHS) is a rare genetic disorder. Although most CCHS associated PHOX2B mutations occur de novo, about 10% of the cases are inherited from apparently asymptomatic parents, thus confirming variable expressivity and incomplete penetrance of PHOX2B mutations. Three asymptomatic parents of children affected with CCHS, and found to carry the same PHOX2B expansion mutations as their siblings, were studied by overnight polysomnography and somatic mosaicism analysis. In one case, significant sleep breathing control anomalies were detected, while the other two resulted in normal. In tissue-specific allele studies, mosaicism with a comparatively low mutant allele proportion was showed in the two unaffected adult carriers. Accurate polysomnography and assessment of the degree of somatic mosaicism should be conducted in asymptomatic carriers of PHOX2B mutations, as they may unmask subclinical but significant anomalies.
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Affiliation(s)
- S Parodi
- Laboratory of Molecular Genetics, G. Gaslini Institute, Genoa, Italy
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79
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Abstract
Current evidence suggests that multiple neural mechanisms contribute to the fatal lethal event in SIDS. The processes may develop from a range of otherwise seemingly-innocuous circumstances, such as unintended external airway obstruction or accidental extreme flexion of the head of an already-compromised structure of the infant upper airway. The fatal event may occur in a sleep state which can suppress muscle tone essential to restore airway patency or exert muscle action to overcome a profound loss of blood pressure. Neural processes that could overcome those transient events with reflexive compensation appear to be impaired in SIDS infants. The evidence ranges from subtle physiological signs that appear very early in life, to autopsy findings of altered neurotransmitter, including serotonergic, systems that have extensive roles in breathing, cardiovascular regulation, and thermal control. Determination of the fundamental basis of SIDS is critical to provide biologic plausibility to SIDS risk reduction messages and to develop specific prevention strategies.
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Affiliation(s)
- Ronald M Harper
- Department of Neurobiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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80
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Novel neuropathologic findings in the Haddad syndrome. Acta Neuropathol 2010; 119:261-9. [PMID: 19844731 DOI: 10.1007/s00401-009-0599-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 10/07/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
Haddad syndrome (congenital central hypoventilation syndrome and Hirschsprung's disease) is a rare disorder for which in-depth neuropathologic analysis is lacking. We report the brain findings in a full-term male infant with Haddad syndrome who died at 27 days of life. Bilateral hypoplasia of the superior temporal lobe and gyral anomalies in the frontal cortex were present. Immunohistochemistry with an antibody to tyrosine hydroxylase (noradrenaline synthesis) demonstrated hypoplasia of the locus coeruleus (implicated in chemoreception) and A5 region. Other findings included delayed maturation of the arcuate nucleus (putative human homologue of ventral medullary neurons in animals critical for chemoreception) and aberrant fascicles in the nucleus of the solitary tract. Efforts to determine the putative gene mutation were unsuccessful. This study implicates novel brain findings in Haddad syndrome mimicking those in murine Phox2b null mutants. This case suggests that abnormalities occur in CCHS in a network of sites critical to chemoreception.
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81
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Carroll MS, Patwari PP, Weese-Mayer DE. Carbon dioxide chemoreception and hypoventilation syndromes with autonomic dysregulation. J Appl Physiol (1985) 2010; 108:979-88. [PMID: 20110549 DOI: 10.1152/japplphysiol.00004.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Respiratory and autonomic disorders of infancy, childhood, and adulthood are a group of disorders that have varying presentation, combined with a range of severity of respiratory control and autonomic nervous system dysfunction. Within this group, congenital central hypoventilation syndrome and rapid onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation, exhibit the greatest respiratory control deficits, requiring supported ventilation as a mainstay of care. The discovery of the key role of the paired-like homeobox 2B gene in autonomic nervous system development, along with the identification of paired-like homeobox 2B gene mutations causing congenital central hypoventilation syndrome, has led to a fruitful dialog between basic scientists and physician-scientists, producing an explosion of knowledge regarding genotype-phenotype correlations in this disorder, as well as important animal models of chemosensory regulation deficit. Though the etiology of rapid onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation is still to be determined, recent studies have begun to carefully delineate the phenotype, suggesting that it too may provide fertile ground for research that both advances our knowledge and improves patient care.
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Affiliation(s)
- Michael S Carroll
- Center for Autonomic Medicine in Pediatrics, Children's Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60614, USA
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82
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Zelko FA, Nelson MN, Leurgans SE, Berry-Kravis EM, Weese-Mayer DE. Congenital central hypoventilation syndrome: neurocognitive functioning in school age children. Pediatr Pulmonol 2010; 45:92-8. [PMID: 19960523 DOI: 10.1002/ppul.21170] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Examine indices of neurocognitive functioning in children with PHOX2B mutation-confirmed neonatal onset congenital central hypoventilation syndrome (CCHS) and relate them to indices of PHOX2B genotype, demographics, and disease severity. METHODS Subjects were 20 patients with PHOX2B mutation-confirmed CCHS diagnosed as neonates who had undergone neurocognitive assessment in the course of clinical care at the Rush Children's Hospital CCHS Center between 1990 and 2006. Neurocognitive variables of interest included Full Scale IQ (FSIQ) and Wechsler-derived marker indices (subtests) of verbal comprehension (Vocabulary), visuoperceptual reasoning (Block Design), working memory (Digit Span), and clerical/processing speed (Coding). RESULTS Single sample t-tests revealed participants' general intelligence index (FSIQ; mean 84.9, SD 23.6) to be lower than the general population, though the range of FSIQ observed was broad. Visuoperceptual reasoning and clerical/visuographic speed marker indices were similarly depressed. These deficits were related to special education participation but not to PHOX2B genotype status or other demographic and clinical risk factors. CONCLUSIONS PHOX2B mutation-confirmed CCHS confers risk for adverse neurocognitive outcome, though the range of functioning observed raises questions about factors that may contribute to neurocognitive variability. Visuoperceptual reasoning and clerical/visuographic speed appear particularly vulnerable. PHOX2B genotype and disease severity indicators were unrelated to neurocognitive indices, possibly due to our modest sample. Future research should employ comprehensive neurocognitive assessment emphasizing visuoperceptual ability, mental speed, attention, and information processing efficiency. Increased recognition and expedited diagnosis with PHOX2B testing should allow larger studies of the relationship between neurocognitive functioning, PHOX2B genotype/mutation, and disease severity and management.
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Affiliation(s)
- Frank A Zelko
- Department of Child and Adolescent Psychiatry, Children's Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60614, USA
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83
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Dilated basilar arteries in patients with congenital central hypoventilation syndrome. Neurosci Lett 2009; 467:139-43. [PMID: 19822189 DOI: 10.1016/j.neulet.2009.10.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 10/05/2009] [Accepted: 10/06/2009] [Indexed: 11/24/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) patients show hypoventilation during sleep and severe autonomic impairments, including aberrant cardiovascular regulation. Abnormal sympathetic patterns, together with increased and variable CO(2) levels, lead to the potential for sustained cerebral vasculature changes. We performed high-resolution T1-weighted imaging in 13 CCHS and 31 control subjects using a 3.0-T magnetic resonance imaging scanner, and evaluated resting basilar and bilateral middle cerebral artery cross-sections. Two T1-weighted image series were acquired; images were averaged and reoriented to common space, and regions containing basilar and both middle cerebral arteries were oversampled. Cross-sections of the basilar and middle cerebral arteries were manually outlined to calculate cross-sectional areas, and differences between and within groups were evaluated. Basilar arteries in CCHS were significantly dilated over control subjects, but both middle cerebral artery cross-sections were similar between groups. No significant differences appeared between left and right middle cerebral arteries within either group. Basilar artery dilation may result from differential sensitivity to high CO(2) over other vascular beds, damage to serotonergic or other chemosensitive cells accompanying the artery, or enhanced microvascular resistance, and that dilation may impair tissue perfusion, leading to further neural injury in CCHS.
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84
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Kumar R, Lee K, Macey PM, Woo MA, Harper RM. Mammillary body and fornix injury in congenital central hypoventilation syndrome. Pediatr Res 2009; 66:429-34. [PMID: 19581831 PMCID: PMC3061446 DOI: 10.1203/pdr.0b013e3181b3b363] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) is accompanied by reduced ventilatory sensitivity to CO2 and O2, respiratory drive failure during sleep, impaired autonomic, fluid, and food absorption regulation, and affective and cognitive deficits, including memory deficiencies. The deficits likely derive from neural injury, reflected as structural damage and impaired functional brain responses to ventilatory and autonomic challenges. Brain structures playing essential memory roles, including the hippocampus and anterior thalamus, are damaged in CCHS. Other memory formation circuitry, the fornix and mammillary bodies, have not been evaluated. We collected two high-resolution T1-weighted image series from 14 CCHS and 31 control subjects, using a 3.0-Tesla magnetic resonance imaging scanner. Image series were averaged and reoriented to a standard template; areas containing the mammillary bodies and fornices were over sampled, and body volumes and fornix cross-sectional areas were calculated and compared between groups. Both left and right mammillary body volumes and fornix cross-sectional areas were significantly reduced in CCHS over control subjects, controlling for age, gender, and intracranial volume. Damage to these structures may contribute to memory deficiencies found in CCHS. Hypoxic processes, together with diminished neuroprotection from micronutrient deficiencies secondary to fluid and dietary absorption issues, may contribute to the injury.
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Affiliation(s)
- Rajesh Kumar
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California 90095, USA
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85
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Amiel J, Dubreuil V, Ramanantsoa N, Fortin G, Gallego J, Brunet JF, Goridis C. PHOX2B in respiratory control: Lessons from congenital central hypoventilation syndrome and its mouse models. Respir Physiol Neurobiol 2009; 168:125-32. [DOI: 10.1016/j.resp.2009.03.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 03/03/2009] [Accepted: 03/04/2009] [Indexed: 11/24/2022]
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86
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Hippocampal volume reduction in congenital central hypoventilation syndrome. PLoS One 2009; 4:e6436. [PMID: 19649271 PMCID: PMC2713409 DOI: 10.1371/journal.pone.0006436] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 06/30/2009] [Indexed: 11/19/2022] Open
Abstract
Children with congenital central hypoventilation syndrome (CCHS), a genetic disorder characterized by diminished drive to breathe during sleep and impaired CO(2) sensitivity, show brain structural and functional changes on magnetic resonance imaging (MRI) scans, with impaired responses in specific hippocampal regions, suggesting localized injury.We assessed total volume and regional variation in hippocampal surface morphology to identify areas affected in the syndrome. We studied 18 CCHS (mean age+/-std: 15.1+/-2.2 years; 8 female) and 32 healthy control (age 15.2+/-2.4 years; 14 female) children, and traced hippocampi on 1 mm(3) resolution T1-weighted scans, collected with a 3.0 Tesla MRI scanner. Regional hippocampal volume variations, adjusted for cranial volume, were compared between groups based on t-tests of surface distances to the structure midline, with correction for multiple comparisons. Significant tissue losses emerged in CCHS patients on the left side, with a trend for loss on the right; however, most areas affected on the left also showed equivalent right-sided volume reductions. Reduced regional volumes appeared in the left rostral hippocampus, bilateral areas in mid and mid-to-caudal regions, and a dorsal-caudal region, adjacent to the fimbria.The volume losses may result from hypoxic exposure following hypoventilation during sleep-disordered breathing, or from developmental or vascular consequences of genetic mutations in the syndrome. The sites of change overlap regions of abnormal functional responses to respiratory and autonomic challenges. Affected hippocampal areas have roles associated with memory, mood, and indirectly, autonomic regulation; impairments in these behavioral and physiological functions appear in CCHS.
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87
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Kumar R, Ahdout R, Macey PM, Woo MA, Avedissian C, Thompson PM, Harper RM. Reduced caudate nuclei volumes in patients with congenital central hypoventilation syndrome. Neuroscience 2009; 163:1373-9. [PMID: 19632307 DOI: 10.1016/j.neuroscience.2009.07.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/16/2009] [Accepted: 07/18/2009] [Indexed: 10/20/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) children show cognitive and affective deficits, in addition to state-specific loss of respiratory drive. The caudate nuclei serve motor, cognitive, and affective roles, and show structural deficits in CCHS patients, based on gross voxel-based analytic procedures. However, the magnitude and regional sites of caudate injury in CCHS are unclear. We assessed global caudate nuclei volumes with manual volumetric procedures, and regional volume differences with three-dimensional surface morphometry in 14 CCHS (mean age+/-SD: 15.1+/-2.3 years; 8 male) and 31 control children (15.1+/-2.4 years; 17 male) using brain magnetic resonance imaging (MRI). Two high-resolution T1-weighted image series were collected using a 3.0 Tesla MRI scanner; images were averaged and reoriented (rigid-body transformation) to common space. Both left and right caudate nuclei were outlined in the reoriented images, and global volumes calculated; surface models were derived from manually-outlined caudate structures. Global caudate nuclei volume differences between groups were evaluated using a multivariate analysis of covariance (covariates: age, gender, and total intracranial volume). Both left and right caudate nuclei volumes were significantly reduced in CCHS over control subjects (left, 4293.45+/-549.05 vs. 4626.87+/-593.41 mm(3), P<0.006; right, 4376.29+/-565.42 vs. 4747.81+/-578.13 mm(3), P<0.004). Regional deficits in CCHS caudate volume appeared bilaterally, in the rostral head, ventrolateral mid, and caudal body. Damaged caudate nuclei may contribute to CCHS neuropsychological and motor deficits; hypoxic processes, or maldevelopment in the condition may underlie the injury.
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Affiliation(s)
- R Kumar
- Department of Neurobiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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88
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Weese-Mayer DE, Rand CM, Berry-Kravis EM, Jennings LJ, Loghmanee DA, Patwari PP, Ceccherini I. Congenital central hypoventilation syndrome from past to future: model for translational and transitional autonomic medicine. Pediatr Pulmonol 2009; 44:521-35. [PMID: 19422034 DOI: 10.1002/ppul.21045] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The modern story of CCHS began in 1970 with the first description by Mellins et al., came most visibly to the public eye with the ATS Statement in 1999, and continues with increasingly fast paced advances in genetics. Affected individuals have diffuse autonomic nervous system dysregulation (ANSD). The paired-like homeobox gene PHOX2B is the disease-defining gene for CCHS; a mutation in the PHOX2B gene is requisite to the diagnosis of CCHS. Approximately 90% of individuals with the CCHS phenotype will be heterozygous for a polyalanine repeat expansion mutation (PARM); the normal allele will have 20 alanines and the affected allele will have 24-33 alanines (genotypes 20/24-20/33). The remaining approximately 10% of individuals with CCHS will have a non-PARM (NPARM), in the PHOX2B gene; these will be missense, nonsense, or frameshift. CCHS and PHOX2B are inherited in an autosomal dominant manner with a stable mutation. Approximately 8% of parents of a CCHS proband will be mosaic for the PHOX2B mutation. A growing number of cases of CCHS are identified after the newborn period, with presentation from infancy into adulthood. An improved understanding of the molecular basis of the PHOX2B mutations and of the PHOX2B genotype/CCHS phenotype relationship will allow physicians to anticipate the clinical phenotype for each affected individual. To best convey the remarkable history of CCHS, and to describe the value of recognizing CCHS as a model for translational and transitional autonomic medicine, we present this review article in the format of a chronological story, from 1970 to the present day.
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Affiliation(s)
- Debra E Weese-Mayer
- Department of Pediatrics, Children's Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA.
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89
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Gallego J, Dauger S. PHOX2B mutations and ventilatory control. Respir Physiol Neurobiol 2009; 164:49-54. [PMID: 18675942 DOI: 10.1016/j.resp.2008.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 07/07/2008] [Accepted: 07/09/2008] [Indexed: 01/08/2023]
Abstract
The transcription factor PHOX2B is essential for the development of the autonomic nervous system. In humans, polyalanine expansion mutations in PHOX2B cause Congenital Central Hypoventilation Syndrome (CCHS), a rare life-threatening disorder characterized by hypoventilation during sleep and impaired chemosensitivity. CCHS is combined with comparatively less severe impairments of autonomic functions including thermoregulation, cardiac rhythm, and digestive motility. Respiratory phenotype analyses of mice carrying an invalidated Phox2b allele (Phox2b+/- mutant mice) or the Phox2b mutation (+7 alanine expansion) found in patients with CCHS (Phox2b(27Ala/+) mice) have shed light on the role for PHOX2B in breathing control and on the pathophysiological mechanisms underlying CCHS. Newborn mice that lacked one Phox2b allele (Phox2b+/-) had sleep apneas and depressed sensitivity to hypercapnia. However, these impairments resolved rapidly, whereas the CCHS phenotype is irreversible. Heterozygous Phox2b(27Ala/+) pups exhibited a lack of responsiveness to hypercapnia and unstable breathing; they died within the first few postnatal hours. The generation of mouse models of CCHS provides tools for evaluating treatments aimed at alleviating both the respiratory symptoms and all other autonomic symptoms of CCHS.
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Affiliation(s)
- Jorge Gallego
- INSERM, U676, Hôpital Robert Debré, 48 Bd Sérurier, 75019 Paris, France.
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90
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Weese-Mayer DE, Berry-Kravis EM, Ceccherini I, Rand CMC. Congenital central hypoventilation syndrome (CCHS) and sudden infant death syndrome (SIDS): kindred disorders of autonomic regulation. Respir Physiol Neurobiol 2009; 164:38-48. [PMID: 18579454 DOI: 10.1016/j.resp.2008.05.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/12/2008] [Accepted: 05/13/2008] [Indexed: 02/02/2023]
Abstract
Congenital central hypoventilation syndrome (CCHS) and sudden infant death syndrome (SIDS) were long considered rare disorders of respiratory control and more recently have been highlighted as part of a growing spectrum of disorders within the rubric of autonomic nervous system (ANS) dysregulation (ANSD). CCHS typically presents in the newborn period with a phenotype including alveolar hypoventilation, symptoms of ANSD and, in a subset of cases, Hirschsprung disease and later tumors of neural crest origin. Study of genes related to autonomic dysregulation and the embryologic origin of the neural crest led to the discovery of PHOX2B as the disease-defining gene for CCHS. Like CCHS, SIDS is thought to result from central deficits in control of breathing and ANSD, although SIDS risk is most likely defined by complex multifactorial genetic and environmental interactions. Some early genetic and neuropathological evidence is emerging to implicate serotonin systems in SIDS risk. The purpose of this article is to review the current understanding of the genetic basis for CCHS and SIDS, and discuss the impact of this information on clinical practice and future research directions.
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Affiliation(s)
- Debra E Weese-Mayer
- Northwestern University Feinberg School of Medicine, Center for Autonomic Medicine in Pediatrics, Children's Memorial Hospital, 2300 Children's Plaza, Chicago, IL 60614, USA.
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91
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Lee P, Su YN, Yu CJ, Yang PC, Wu HD. PHOX2B mutation-confirmed congenital central hypoventilation syndrome in a Chinese family: presentation from newborn to adulthood. Chest 2009; 135:537-544. [PMID: 19201717 DOI: 10.1378/chest.08-1664] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Congenital central hypoventilation syndrome (CCHS) is characterized by compromised chemoreflexes resulting in sleep hypoventilation. We report a Chinese family with paired-like homeobox 2B (PHOX2B) mutation-confirmed CCHS, with a clinical spectrum from newborn to adulthood, to increase awareness of its various manifestations. METHODS After identifying central hypoventilation in an adult man (index case), clinical evaluation was performed on the complete family, which consisted of the parents, five siblings, and five offspring. Pulmonary function tests, overnight polysomnography, arterial blood gas measurements, hypercapnia ventilatory response, and PHOX2B gene mutation screening were performed on living family members. Brain MRI, 24-h Holter monitoring, and echocardiography were performed on members with clinically diagnosed central hypoventilation. RESULTS The index patient and four offspring manifested clinical features of central hypoventilation. The index patients had hypoxia and hypercapnia while awake, polycythemia, and hematocrit levels of 70%. The first and fourth children had frequent cyanotic spells, and both died of respiratory failure. The second and third children remained asymptomatic until adulthood, when they experienced impaired hypercapnic ventilatory response. The third child had nocturnal hypoventilation with nadir pulse oximetric saturation of 59%. Adult-onset CCHS with PHOX2B gene mutation of the + 5 alanine expansions were confirmed in the index patient and the second and third children. The index patient and the third child received ventilator support system bilevel positive airway pressure treatment, which improved the hypoxemia, hypercapnia, and polycythemia without altering their chemosensitivity. CONCLUSIONS Transmission of late-onset CCHS is autosomal-dominant. Genetic screening of family members of CCHS probands allows for early diagnosis and treatment.
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Affiliation(s)
- Peilin Lee
- Center of Sleep Disorder, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Ning Su
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chong-Jen Yu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Pan-Chyr Yang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Huey-Dong Wu
- Department of Integrated Diagnostics and Therapeutics, National Taiwan University Hospital, Taipei, Taiwan.
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92
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Wu HT, Su YN, Hung CC, Hsieh WS, Wu KJ. Interaction between PHOX2B and CREBBP mediates synergistic activation: Mechanistic implications of PHOX2B mutants. Hum Mutat 2009; 30:655-60. [DOI: 10.1002/humu.20929] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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93
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Matsuyama M, Nakazawa K, Katou M, Ota K, Masuko H, Iizuka T, Mori T, Hayashi H, Hayashihara K, Saito T, Satoh M, Hizawa N. Central alveolar hypoventilation syndrome due to surgical resection for bulbar hemangioblastoma. Intern Med 2009; 48:925-30. [PMID: 19483363 DOI: 10.2169/internalmedicine.48.1804] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 29-year-old man with a history of resected bulbar hemangioblastoma was admitted to hospital with nighttime breathing disturbance, but with apparently normal breathing while awake. After diagnostic work-up, including polysomnographic testing, he was diagnosed as having central alveolar hypoventilation syndrome due to surgical resection for bulbar hemangioblastoma. Non-invasive positive pressure ventilation (NIPPV) via oronasal facemask was given for nocturnal ventilatory support. Two months after leaving our hospital, he was readmitted because of aspiration pneumonia. The pneumonia was successfully treated with antibiotics, but the desaturation during sleep worsened despite non-invasive ventilatory support. Higher bi-level positive pressure using a full facemask successfully alleviated sleep hypoventilation and apnea. To the best of our knowledge, this is the first case report of central alveolar hypoventilation syndrome due to surgical resection for bulbar hemangioblastoma.
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Affiliation(s)
- Masashi Matsuyama
- Department of Respiratory Medicine, National Hospital Organization Ibarakihigashi National Hospital, Ibaraki
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Little R. A 2-year old with no ventilator requirement but who cannot be extubated. Semin Pediatr Neurol 2008; 15:157-9; discussion 159. [PMID: 19073316 DOI: 10.1016/j.spen.2008.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A 2-year-old boy was intubated during treatment for pneumonia. After resolution of the infection, he had no pulmonary requirement for ventilation and could function without it while awake. When he slept, however, he would have decreasing respiratory effort, increasing hypercapnia, and episodic apnea. This report provides an example of late-onset congenital central hypoventilation syndrome.
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Affiliation(s)
- Robert Little
- Phoenix Children's Hospital, Phoenix, AZ 85016, USA.
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Affiliation(s)
- Hiren Muzumdar
- Division of Respiratory and Sleep Medicine, The Children's Hospital at Montefiore, Albert Einstein College of Medicine, 3415 Bainbridge Avenue, Bronx, NY 10467 2490, USA
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Liess BD, Dost JS, Templer JW, Tobias JD. Congenital central alveolar hypoventilation syndrome (Ondine's curse) with survival into adulthood. Clin Pediatr (Phila) 2008; 47:941-6. [PMID: 18599875 DOI: 10.1177/0009922808320701] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ondine's curse or central alveolar hypoventilation (CCAH) syndrome is a disorder of the autonomic nervous system resulting in respiratory dysregulation. The clinical outcome is typically poor, with few individuals living into adulthood and even fewer surviving to adulthood with normal neurological function. Our patient initially presented following an uncomplicated delivery with hypotonia, poor respiratory effort, and hypoxemia that required ventilatory support. Laboratory workup, radiographic evaluation, and ancillary testing ruled out brain stem lesions, neuromuscular diseases, cardiovascular and pulmonary disease, and metabolic disorders, resulting in a diagnosis of CCAH syndrome. The patient underwent tracheotomy and chronic ventilatory support. Close long-term management and appropriate treatment modifications have provided for an excellent outcome and good quality of life. The patient is currently 22 years old and is earning her teaching degree for K-12 art education. A combination of early recognition and a multidisciplinary approach may lead to a successful outcome in patients with CCAH syndrome.
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Affiliation(s)
- Benjamin D Liess
- Department of Otolaryngology-Head and Neck Surgery, University of Missouri-Columbia School of Medicine, Columbia, Missouri, USA
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97
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Bougnères P, Pantalone L, Linglart A, Rothenbühler A, Le Stunff C. Endocrine manifestations of the rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation, and neural tumor syndrome in childhood. J Clin Endocrinol Metab 2008; 93:3971-80. [PMID: 18628522 DOI: 10.1210/jc.2008-0238] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation, and neural tumor (ROHHADNET) is a newly described syndrome that can cause cardiorespiratory arrests and death. It mimics several endocrine disorders or genetic obesity syndromes during early childhood and is associated with various forms of hypothalamic-pituitary endocrine dysfunctions that have not yet been fully investigated. OBJECTIVE The current report aspires to facilitate the earlier recognition and appropriate treatment of the ROHHADNET syndrome when children present with various endocrine manifestations, such as early obesity, growth failure, pseudo-Cushing's syndrome, glucocorticoid insufficiency, congenital hypopituitarism, or adrenal tumors. A more widespread knowledge of the syndrome will help characterize its molecular origin. DESIGN Endocrine studies were performed in six patients admitted for seemingly common early-onset obesity associated with growth failure in five of them. The six patients later showed distinctive features of the ROHHADNET syndrome. RESULTS Abnormalities of the pituitary adrenal axis ranged from a true Cushing-like profile (one of six), to glucocorticoid deficiency with normal ACTH (two of six). Complete GH deficiency with low IGF-I was observed in four of six, hypogonadotropic hypogonadism in four of six, hyperprolactinemia in six of six, and various degrees of TSH/T(4) abnormalities in five of five patients. All had increased natremia without diabetes insipidus. Five children had unilateral macroscopic adrenal ganglioneuroma. Two patients died at 8.5 and 12 yr of age. CONCLUSIONS Various hypothalamic-pituitary endocrine dysfunctions are associated with ROHHADNET, carrying a risk of misdiagnosis until other elements of the syndrome make it more easily recognizable. Given its severity, ROHHADNET syndrome should be considered in all cases of isolated, rapid, and early obesity.
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Affiliation(s)
- Pierre Bougnères
- Department of Pediatric Endocrinology, Hôpital Saint Vincent de Paul, 75014 Paris, France.
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98
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Parodi S, Baglietto MP, Pini Prato A, Caroli F, Garaventa A, Ceccherini I, Ottonello G. A novel missense mutation in the PHOX2B gene is associated with late onset central hypoventilation syndrome. Pediatr Pulmonol 2008; 43:1036-9. [PMID: 18785257 DOI: 10.1002/ppul.20892] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report the case of a 15-month-old male suffering from Late Onset Congenital Central Hypoventilation Syndrome and recto-sigmoid Hirschsprung's disease, an association that has not been reported thus far. Nevertheless, our patient showed a missense mutation of the PHOX2B gene already known in isolated late onset central hypoventilation, resulting in a substitution of the Ala140 residue with a Glu residue (p.A140E). The present association of LO-CHS and HSCR in a patient harboring a rare and atypical PHOX2B mutation allows to refine the mutational spectrum of this disease and suggests individualized ventilatory care along with specific surgical and oncological approaches.
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Affiliation(s)
- Sara Parodi
- Laboratory of Molecular Genetics, G. Gaslini Institute, Genoa, Italy
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Kinney HC. Structural abnormalities in the brainstem and cerebellum in congenital central hypoventilation syndrome: commentary on the article by Kumar et al. on page 275. Pediatr Res 2008; 64:226-7. [PMID: 18714200 DOI: 10.1203/pdr.0b013e318185e155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hannah C Kinney
- Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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Kumar R, Macey PM, Woo MA, Alger JR, Harper RM. Diffusion tensor imaging demonstrates brainstem and cerebellar abnormalities in congenital central hypoventilation syndrome. Pediatr Res 2008; 64:275-80. [PMID: 18458651 PMCID: PMC2682538 DOI: 10.1203/pdr.0b013e31817da10a] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Congenital central hypoventilation syndrome (CCHS) patients show reduced breathing drive during sleep, decreased hypoxic and hypercapnic ventilatory responses, and autonomic and affective deficits, suggesting both brainstem and forebrain injuries. Forebrain damage was previously described in CCHS, but methodological limitations precluded detection of brainstem injury, a concern because genetic mutations in CCHS target brainstem autonomic nuclei. To assess brainstem and cerebellar areas, we used diffusion tensor imaging-based measures, namely axial diffusivity, reflecting water diffusion parallel to fibers, and sensitive to axonal injury, and radial diffusivity, measuring diffusion perpendicular to fibers, and indicative of myelin injury. Diffusion tensor imaging was performed in 12 CCHS and 26 controls, and axial and radial diffusivity maps were compared between groups using analysis of covariance (covariates; age and gender). Increased axial diffusivity in CCHS appeared within the lateral medulla and clusters with injury extended from the dorsal midbrain through the periaqueductal gray, raphé, and superior cerebellar decussation, ventrally to the basal-pons. Cerebellar cortex and deep nuclei, and the superior and inferior cerebellar peduncles showed increased radial diffusivity. Midbrain, pontine, and lateral medullary structures, and the cerebellum and its fiber systems are injured in CCHS, likely contributing to the characteristics found in the syndrome.
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Affiliation(s)
- Rajesh Kumar
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California 90095-1763, USA
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