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Kang PB, Krishnamoorthy KS, Jones RM, Shapiro FD, Darras BT. Atypical presentations of spinal muscular atrophy type III (Kugelberg-Welander disease). Neuromuscul Disord 2006; 16:492-4. [PMID: 16797181 DOI: 10.1016/j.nmd.2006.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 05/04/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
Spinal muscular atrophy type III (SMA III, Kugelberg-Welander disease) typically presents with symmetric proximal weakness, areflexia, and hypotonia. We present four children with spinal muscular atrophy type III who had atypical phenotypes. Three patients clearly had asymmetric weakness at presentation and two had upper motor neuron signs in the lower extremities (one patient had both features). Two of the patients had prolonged evaluations before the diagnosis was made. All patients had Gowers signs and two had pes planus. In patients with proximal muscle weakness the presence of asymmetrical weakness, upper motor neuron signs, or both, may be compatible with spinal muscular atrophy type III. The diagnosis of spinal muscular atrophy should be considered when other possibilities have been excluded.
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Howell RR, Byrne B, Darras BT, Kishnani P, Nicolino M, van der Ploeg A. Diagnostic challenges for Pompe disease: An under-recognized cause of floppy baby syndrome. Genet Med 2006; 8:289-96. [PMID: 16702878 DOI: 10.1097/01.gim.0000204462.42910.b8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Pompe disease, a disorder caused by a deficiency in the lysosomal enzyme acid alpha glucosidase, is frequently overlooked as a cause of floppy baby syndrome. The accurate diagnosis of floppy baby syndrome requires the sequential evaluation of medical causes (e.g., hypothyroidism, sepsis, malnutrition, malabsorption, congenital heart disease), neurologic etiologies (central [cerebral] and peripheral [lower motor unit]) and anatomic characteristics of the abnormality. Cardiomegaly on chest x-ray in a patient with floppy baby syndrome should alert the pediatrician to suspect Pompe disease. Based on this finding, further work-up or referral to a specialist can be considered. Pompe disease requires immediate attention. Symptomatic intervention of this disorder should be initiated at the earliest time possible to maximize the potential benefit from therapy and to prevent irreversible organ damage. Moreover, early diagnosis is important for providing parents with realistic information about their child's prognosis, and where appropriate, professional genetic counseling. Enzyme replacement therapy (ERT) with recombinant human GAA is currently being evaluated in clinical trials; the future availability of this option makes early identification of this condition even more critical. This article presents a unified view on the optimal approach to the accurate diagnosis of Pompe disease and to its recognition as one of the possible and treatable causes of floppy baby syndrome.
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Abstract
BACKGROUND Facioscapulohumeral muscular dystrophy causes winging of the scapula and weakness and discomfort of the shoulder. Surgical stabilization of the scapula to the posterior part of the chest wall permits shoulder abduction and flexion by the deltoid muscle. In the present retrospective study, we describe our experience with eleven scapulothoracic fusion procedures that were performed for the treatment of the infantile and adolescent forms of the disease. METHODS Eleven procedures were performed in eight patients, including four male patients (one of whom had bilateral involvement and three of whom had unilateral involvement) and four female patients (two of whom had bilateral involvement and two of whom had unilateral involvement). One of the female patients had the infantile variant, whereas all other patients had the adolescent form of the disease. The mean age at the time of the eleven operations was seventeen years. The scapula was fused to the thorax in 25 degrees of abduction with use of 16-gauge wires, a plate or washers on the posteromedial scapular surface to prevent wire pull-out, and iliac crest autograft. After a mean duration of follow-up of 6.3 years, all patients were assessed clinically and radiographically. RESULTS In all cases, scapular winging and shoulder fatigue and pain were initially eliminated. In the first year after the operation, active abduction and flexion of the shoulder improved to a mean of 145 degrees (range, 110 degrees to 160 degrees ) and 144 degrees (range, 130 degrees to 160 degrees ), respectively, from a preoperative mean of 75 degrees (range, 70 degrees to 90 degrees ). At the time of the final assessment (mean, 6.3 years postoperatively), abduction and flexion were maintained at a mean of 139 degrees and 134 degrees , respectively, in seven shoulders; however, in the remaining four shoulders, both of these motions had decreased to a mean of 48 degrees because of progressive loss of deltoid muscle strength. In two cases, prominent subcutaneous wires required trimming. There were no other complications. CONCLUSIONS Scapulothoracic fusion relieves shoulder fatigue and pain, allows for smooth functional abduction and flexion of the upper extremity, and improves the appearance of the neck and shoulder in patients who have symptomatic scapular winging due to facioscapulohumeral muscular dystrophy. The procedure is associated with a low risk of complications. Progression of the disease affecting the deltoid muscle can cause loss of abduction, but the other benefits of stabilization persist. LEVEL OF EVIDENCE Therapeutic Level IV.
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Wu JY, Kuban KCK, Allred E, Shapiro F, Darras BT. Association of Duchenne muscular dystrophy with autism spectrum disorder. J Child Neurol 2005; 20:790-5. [PMID: 16417872 DOI: 10.1177/08830738050200100201] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We hypothesize that Duchenne muscular dystrophy and autism spectrum disorder/pervasive developmental disorder co-occur with a greater than random frequency. In this study, we set out to reject the hypothesis that Duchenne muscular dystrophy and autism spectrum disorder/pervasive developmental disorder co-occur no more often than expected by chance. Two index cases and six additional boys with concomitant Duchenne muscular dystrophy and autism spectrum disorder were identified in a muscular dystrophy clinic that approximates the total number of Duchenne muscular dystrophy boys (158) in the state of Massachusetts. The rate of prevalence (6 of 158) was compared with the prevalence rate of autism spectrum disorder in boys in the general population (1.6 in 1,000). We rejected the hypothesis that Duchenne muscular dystrophy and autism spectrum disorder co-occurrence was likely to be explained by chance (P = .006). We identify a previously unrecognized association of Duchenne muscular dystrophy with autism spectrum disorder. Further work might elucidate the level of association between these two conditions, either at the genetic or at the protein level, and might clarify, at least partially, the neurobiologic mechanisms associated with autism spectrum disorder.
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Fleming FJ, Vytopil M, Chaitow J, Jones HR, Darras BT, Ryan MM. Thalidomide neuropathy in childhood. Neuromuscul Disord 2004; 15:172-6. [PMID: 15694139 DOI: 10.1016/j.nmd.2004.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2004] [Revised: 10/11/2004] [Accepted: 10/15/2004] [Indexed: 11/15/2022]
Abstract
Thalidomide was withdrawn from world markets in 1961 following recognition of its teratogenic effects. More recently, however, thalidomide treatment has been reintroduced to adult and paediatric practice for a variety of dermatologic, immunologic, rheumatologic and neoplastic disorders. Neuropathy is a significant side effect of thalidomide therapy, which may limit its clinical use. We report four cases of sensorimotor axonal neuropathy in children aged 10-15 years, treated with thalidomide for myxopapillary ependymoma, Crohn's disease and recurrent giant aphthous ulceration. Thalidomide neuropathy is often associated with proximal weakness and may progress even after discontinuation of treatment, in the phenomenon of 'coasting'. Children treated with thalidomide should undergo regular neurophysiologic studies in order to detect presymptomatic or progressive peripheral neuropathy.
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Ullrich NJ, Riviello JJ, Darras BT, Donner EJ. Electroencephalographic correlate of juvenile Huntington's disease. J Child Neurol 2004; 19:541-3. [PMID: 15526960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The spectrum of clinical disease in juvenile Huntington's disease differs from that seen in adults. Younger patients often present with seizures, dystonia and rigidity. The mechanism and type of seizures, timing of onset and electrographic features have not been well characterized in either adults or children. We describe the electroencephalographic findings observed in a young child with Huntington's disease who presented with motor regression and seizures. Recordings demonstrated bilateral posterior quadrant epileptiform discharges and occipital intermittent rhythmic delta activity, generally considered a nonspecific abnormality. These findings have not been reported in adult or juvenile Huntington's disease. Its presence in proximity to bilateral posterior spikes suggests that occipital intermittent rhythmic delta activity is an epileptiform abnormality, on a continuum with the posterior spike-and-wave discharges. Intermittent rhythmic delta activity can occur secondary to either the subcortical gray-matter disease or the associated seizure disorder. Huntington's disease should be considered in the differential diagnosis of young children who present with seizures and developmental regression.
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Abstract
This review presents insights gained over 24 years of clinical and laboratory evaluations of children, newborn to 18 years of age, who present with acute weakness in the intensive care setting. The differential diagnosis of neuromuscular disorders in these cases begins with recognition of three categories-the infant and toddler, the older child and adolescent, and the child with critical illness-within which predisposition to specific disorders may be identified. Disorders originating from anterior horn cell, peripheral nerve, neuromuscular junction, and muscle cell are discussed with emphasis on presentation and electrophysiologic findings. Nerve conduction studies, electromyography, electroencephalography, cerebrospinal fluid analysis, and magnetic resonance imaging each play important diagnostic roles in the differentiation of neuromuscular disorders in the critically ill child. Case studies suggest the wide range of presentations these disorders may make to the pediatrician or pediatric neurologist.
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Cameron CL, Kang PB, Burns TM, Darras BT, Jones HR. Multifocal slowing of nerve conduction in metachromatic leukodystrophy. Muscle Nerve 2004; 29:531-6. [PMID: 15052618 DOI: 10.1002/mus.10569] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Polyneuropathy is invariably associated with the late-infantile form of metachromatic leukodystrophy (MLD), and occurs frequently in the early juvenile, juvenile, and adult variants. Uniform slowing of nerve conduction velocity is the neurophysiologic hallmark of metachromatic leukodystrophy and other inherited demyelinating polyneuropathies. To evaluate the consistency of this principle, we reviewed nerve conduction studies in 9 children with late-infantile or early-juvenile metachromatic leukodystrophy. Each child had significant slowing of motor nerve conduction velocity (NCV). The compound muscle action potentials showed abnormal temporal dispersion in 3 of the 9 children, which is usually regarded as the hallmark of acquired demyelinating polyneuropathies. There are reports of multifocal slowing in other hereditary processes including X-linked Charcot-Marie-Tooth disease, hereditary neuropathy with liability to pressure palsies, and adrenomyeloneuropathy. Although multifocal NCV slowing in a child with polyneuropathy is seen most commonly in acquired conditions, a hereditary process, including MLD, cannot always be excluded in this setting.
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Ryan MM, Tilton A, De Girolami U, Darras BT, Jones HR. Paediatric mononeuritis multiplex: a report of three cases and review of the literature. Neuromuscul Disord 2003; 13:751-6. [PMID: 14561499 DOI: 10.1016/s0960-8966(03)00099-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mononeuritis multiplex results from disease processes causing multifocal injury to the peripheral nerves, with or without involvement of one or more cranial nerves. Most reported cases of paediatric mononeuritis multiplex have been related to autoimmune disorders. We present clinical and neurophysiologic findings in three cases of multiple mononeuropathy occurring in adolescence, with onset at ages 16, 17 and 13 years. Two of these cases were related to systemic vasculitis, one possibly representing a paediatric case of non-systemic vasculitis. Sural nerve biopsy confirmed the diagnosis of vasculitis in one patient with systemic lupus erythematosus, but was non-diagnostic in another case. Mononeuritis multiplex is an extremely uncommon form of acquired peripheral neuropathy in childhood. We discuss the differential diagnosis and review previous descriptions of this rare condition.
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Kang PB, Lidov HGW, David WS, Torres A, Anthony DC, Jones HR, Darras BT. Diagnostic value of electromyography and muscle biopsy in arthrogryposis multiplex congenita. Ann Neurol 2003; 54:790-5. [PMID: 14681888 DOI: 10.1002/ana.10769] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Arthrogryposis multiplex congenita (AMC), a clinical syndrome characterized by multiple congenital joint contractures, frequently is caused by lesions in the peripheral nervous system. Two standard tests for the evaluation of the motor unit are nerve conduction studies/electromyography (NCS/EMG) and muscle biopsy. We reviewed the diagnostic value of these two studies in the evaluation of AMC over a 23-year period, analyzing 38 patients with AMC who had NCS/EMG, muscle biopsy, or both. Final diagnoses were classified as neurogenic (8 patients), myopathic (10 patients), "other" (12 patients), or unknown (8 patients). Neither test alone had consistently high sensitivities, positive predictive values, or specificities. However, when NCS/EMG and muscle biopsy were concordant for neurogenic or myopathic findings, they were more accurate than either test alone, especially for neurogenic diseases. Test results were most commonly discordant in patients with "other" or unknown diagnoses. These findings suggest that when the clinical evaluation indicates a specific syndromic, developmental, or exogenous cause, NCS/EMG and muscle biopsy are not helpful and may not need to be performed. When the history, examination, and genetic evaluation are unrevealing, NCS/EMG and muscle biopsy together provide valuable diagnostic information.
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Yao DC, Tolan DR, Murray MF, Harris DJ, Darras BT, Geva A, Neufeld EJ. Hemolytic anemia and severe rhabdomyolysis caused by compound heterozygous mutations of the gene for erythrocyte/muscle isozyme of aldolase, ALDOA(Arg303X/Cys338Tyr). Blood 2003; 103:2401-3. [PMID: 14615364 DOI: 10.1182/blood-2003-09-3160] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Aldolase (E.C. 4.1.2.13), a homotetrameric protein encoded by the ALDOA gene, converts fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. Three isozymes are encoded by distinct genes. The sole aldolase present in red blood cells and skeletal muscle is the A isozyme. We report here the case of a girl of Sicilian descent with aldolase A deficiency. Clinical manifestations included transfusion-dependent anemia until splenectomy at age 3 and increasing muscle weakness, with death at age 4 associated with rhabdomyolysis and hyperkalemia. Sequence analysis of the ALDOA coding regions revealed 2 novel heterozygous ALDOA mutations in conserved regions of the protein. The paternal allele encoded a nonsense mutation, Arg303X, in the enzyme-active site. The maternal allele encoded a missense mutation, Cys338Tyr, predicted to cause enzyme instability. This is the most severely affected patient reported to date and only the second with both rhabdomyolysis and hemolysis.
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Milunsky JM, Maher TA, Loose BA, Darras BT, Ito M. XL PCR for the detection of large trinucleotide expansions in juvenile Huntington's disease. Clin Genet 2003; 64:70-3. [PMID: 12791042 DOI: 10.1034/j.1399-0004.2003.00108.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Juvenile Huntington's disease (HD) becomes clinically manifest before 20 years of age. The diagnosis of HD is based on family history, characteristic clinical findings, and the detection of an expansion of a CAG polyglutamine tract in the Huntingtin gene. Juvenile HD is characterized by paternal anticipation and large CAG expansions that may be missed using routine molecular analysis. We have developed an easy, rapid, and reliable modified PCR method using XL (Extra Long) PCR that allowed us to diagnose one of the youngest children reported with juvenile HD. Without this innovation we would not have been able to demonstrate the large CAG expansion. This assay could become part of a standard protocol for HD testing in molecular diagnostic laboratories.
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Abstract
Mononeuropathies are uncommon in childhood but can be a cause of significant disability. A considerable proportion of pediatric peroneal palsies arise as iatrogenic complications of casting, footboards, and intraoperative positioning. This article provides a description of a patient who developed bilateral peroneal palsies after cardiac transplantation. Factors predisposing this patient to neuropathy included hemophilia and prolonged immobilization, with focal involvement of the peroneal nerves being likely related to the use of ankle-foot orthoses. Peroneal nerve palsies are a significant, but potentially avoidable, iatrogenic complication of lower-extremity orthoses.
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Darras BT. Role of EMG in the evaluation of presumed myopathies in the era of DNA analysis. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2003; 53:133-8. [PMID: 12740987 DOI: 10.1016/s1567-424x(09)70148-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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191
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Cooper LL, Hansen RM, Darras BT, Korson M, Dougherty FE, Shoffner JM, Fulton AB. Rod photoreceptor function in children with mitochondrial disorders. ARCHIVES OF OPHTHALMOLOGY (CHICAGO, ILL. : 1960) 2002; 120:1055-62. [PMID: 12149059 DOI: 10.1001/archopht.120.8.1055] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To test the hypothesis that function of the rod photoreceptors is abnormal in pediatric patients with mitochondrial disorders. METHODS Patients (n = 22; median age, 5 years) with a deficiency of 1 or more of the mitochondrial enzyme complexes, or a mutation in mitochondrial DNA, were studied by means of scotopic, full-field electroretinography (ERG). The conditions of ERG testing allowed derivation of the parameters of the activation of rod phototransduction from the ERG a-wave, and postreceptoral function from b-wave and P(2) stimulus-response functions. The deactivation of phototransduction was studied in 5 patients. The patients' ERG responses were compared with those of healthy control subjects (n = 25). RESULTS Responses from 19 patients were sufficient for analysis of rod photoreceptor and postreceptoral function. Saturated amplitudes of the rod photoresponse and b-wave sensitivity were significantly depressed in the patients. Saturated amplitudes of rod cell and P(2) responses were correlated. The kinetics of deactivation of phototransduction were slowed even if the kinetics of activation were normal. CONCLUSIONS In patients with mitochondrial disorders, some abnormalities of the scotopic ERG responses originate in the rod photoreceptors, but postreceptoral processes may also be abnormal. From a practical perspective, ERG testing can contribute to diagnosis of mitochondrial disorders.
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Bönnemann CG, Wong J, Jones KJ, Lidov HGW, Feener CA, Shapiro F, Darras BT, Kunkel LM, North KN. Primary gamma-sarcoglycanopathy (LGMD 2C): broadening of the mutational spectrum guided by the immunohistochemical profile. Neuromuscul Disord 2002; 12:273-80. [PMID: 11801399 DOI: 10.1016/s0960-8966(01)00276-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
An important step in the diagnostic evaluation of a patient with recessive limb-girdle muscular dystrophy is the immunohistochemical analysis of the components of the sarcoglycan complex in a muscle biopsy specimen. Even though a primary mutation in any of the four sarcoglycan genes (alpha-, beta-,gamma-, delta-sarcoglycan) may cause secondary deficiencies in all the other sarcoglycan proteins, more specific immunohistochemical patterns have emerged with the potential to guide and abbreviate the necessary molecular genetic investigations. In gamma-sarcoglycan mutations, the pattern consists of absent or prominently reduced gamma-sarcoglycan immunoreactivity in combination with reduced but detectable immunoreactivity for the other components, with preservation of delta-sarcoglycan. In five consecutive patients, this pattern was able to predict primary gamma-sarcoglycan mutations. Five different mutations were found, including a recurrent novel splice mutation, a large deletion of the entire gene and a novel missense mutation (Leu90Ser). The mutation Cys283Tyr, previously restricted to Gypsy populations was found in compound heterozygosity with del521T, common in north Africa. The variety of known and novel mutations found indicates that the immunohistochemical profile of gamma-sarcoglycan mutations is not restricted to a particular mutation or type of mutation, but rather is a general reflection of the effect of gamma-sarcoglycan mutations on the composition of the sarcoglycan complex. Complete immunohistochemical analysis with all available sarcoglycan antibodies, therefore, is a useful tool to guide the molecular genetic investigations that are necessary to arrive at the correct genetic diagnosis in a given case.
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Abstract
Osteoid osteomas are benign bone tumors, most commonly located in the femur or tibia. In young children, these tumors can be extremely difficult to diagnose. They commonly present nonspecifically with gait disturbance and pain and characteristically respond well to mild pain relievers. We report two patients who presented with neurologic signs, including atrophy, weakness, and diminished deep tendon reflexes of the affected limb. These two patients demonstrate that osteoid osteomas of the lower extremities can present with neurologic signs, and proper diagnosis requires a detailed history and clinical awareness of this phenomenon.
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Bennett RR, den Dunnen J, O'Brien KF, Darras BT, Kunkel LM. Detection of mutations in the dystrophin gene via automated DHPLC screening and direct sequencing. BMC Genet 2001; 2:17. [PMID: 11710958 PMCID: PMC59832 DOI: 10.1186/1471-2156-2-17] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2001] [Accepted: 10/17/2001] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Currently molecular diagnostic laboratories focus only on the identification of large deletion and duplication mutations (spanning one exon or more) for Duchenne Muscular Dystrophy (DMD) yielding 65% of causative mutations. These mutations are detected by an existing set of multiplexed polymerase chain reaction (PCR) primer pairs. Due to the large size of the dystrophin gene (79 exons), finding point mutations (substitutions, deletions or insertions of one or several nucleotides) has been prohibitively expensive and laborious. The aim of this project was to develop an effective and convenient method of finding all, or most, mutations in the dystrophin gene with only a moderate increase in cost. RESULTS Using denaturing high performance liquid chromatography (DHPLC) screening and direct sequencing, 86 PCR amplicons of genomic DNA from the dystrophin gene were screened for mutations in eight patients diagnosed with DMD who had tested negative for large DNA rearragements. Mutations likely to be disease-causative were found in six of the eight patients. All 86 amplicons from the two patients in whom no likely disease-causative mutations were found were completely sequenced and only polymorphisms were found. CONCLUSIONS We have shown that it is now feasible for clinical laboratories to begin testing for both point mutations and large deletions/duplications in the dystrophin gene. The detection rate will rise from 65% to greater than 92% with only a moderate increase in cost.
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Brown CA, Lanning RW, McKinney KQ, Salvino AR, Cherniske E, Crowe CA, Darras BT, Gominak S, Greenberg CR, Grosmann C, Heydemann P, Mendell JR, Pober BR, Sasaki T, Shapiro F, Simpson DA, Suchowersky O, Spence JE. Novel and recurrent mutations in lamin A/C in patients with Emery-Dreifuss muscular dystrophy. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 102:359-67. [PMID: 11503164 DOI: 10.1002/ajmg.1463] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is characterized by slowly progressive muscle wasting and weakness; early contractures of the elbows, Achilles tendons, and spine; and cardiomyopathy associated with cardiac conduction defects. Clinically indistinguishable X-linked and autosomal forms of EDMD have been described. Mutations in the STA gene, encoding the nuclear envelope protein emerin, are responsible for X-linked EDMD, while mutations in the LMNA gene encoding lamins A and C by alternative splicing have been found in patients with autosomal dominant, autosomal recessive, and sporadic forms of EDMD. We report mutations in LMNA found in four familial and seven sporadic cases of EDMD, including seven novel mutations. Nine missense mutations and two small in-frame deletions were detected distributed throughout the gene. Most mutations (7/11) were detected within the LMNA exons encoding the central rod domain common to both lamins A/C. All of these missense mutations alter residues in the lamin A/C proteins conserved throughout evolution, implying an essential structural and/or functional role of these residues. One severely affected patient possesed two mutations, one specific to lamin A that may modify the phenotype of this patient. Mutations in LMNA were frequently identified among patients with sporadic and familial forms of EDMD. Further studies are needed to identify the factors modifying disease phenotype among patients harboring mutations within lamin A/C and to determine the effect of various mutations on lamin A/C structure and function.
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196
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Zarifi MK, Tzika AA, Astrakas LG, Poussaint TY, Anthony DC, Darras BT. Magnetic resonance spectroscopy and magnetic resonance imaging findings in Krabbe's disease. J Child Neurol 2001; 16:522-6. [PMID: 11453451 DOI: 10.1177/088307380101600713] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two twins with late infantile globoid cell leukodystrophy of Krabbe's disease were studied with conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy. Brain MRI demonstrated brain atrophy with extensive bilateral symmetric abnormal T2 signal in the posterior periventricular white matter, parietal lobes, corona radiata, centrum semiovale, and splenium of the corpus callosum. Magnetic resonance imaging-guided proton magnetic resonance spectroscopy revealed prominent peaks from choline-containing compounds, total creatine, and inositols. The N-acetylaspartate peak was markedly reduced, and the choline-to-N-acetylaspartate ratio was abnormally high; in one of the twins, lactic acid was also detected. The constellation of magnetic resonance spectroscopy findings is indicative of extensive demyelination, gliosis, and loss of axons in the involved white matter; the latter two events occur in the later stages of globoid cell leukodystrophy. In conjunction with brain MRI, these magnetic resonance spectroscopy findings may alert clinicians to the possibility of leukodystrophy in children with progressive encephalopathy.
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197
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Abstract
The recognition of uncommon pediatric motor unit disorders or unusual clinical presentations of common illnesses, such as Guillain-Barré syndrome (GBS), have increased the need for electromyography (EMG) in childhood critical care units. There are two different clinical sets, one appropriate to newborns and infants and the other to older children. Some illnesses that present as an acute floppy infant are not found in the differential diagnosis of motor unit disorders in the older child or adult. These include spinal muscular atrophy, postvaccine poliomyelitis, intrauterine GBS, infantile botulism, and severe myopathies, such as myotonia dystrophy, and some glycogen storage diseases. An appreciation of the neurophysiological maturational norms is essential to an effective pediatric EMG consultation for children ages 0-3 years. Additionally, the neuromuscular complications of extended intubation and sepsis in children are gaining broader recognition. An increased dialogue between clinical neurophysiologists and pediatric neurologists and intensivists in both neonatal and pediatric intensive care units is essential.
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Lin AE, Liu Q, Mannheim GB, Darras BT. Exclusion of growth factor gene mutations as a common cause of Sotos syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 98:101-2. [PMID: 11426446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Sotos syndrome is characterized by somatic overgrowth, i.e., macrocephaly and tall stature. Because the cause and pathogenesis of Sotos syndrome remain unknown, we selected nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) as possible genes mutated in Sotos syndrome. In seven patients with the classic phenotype, we excluded mutations in these growth factor genes. It is possible that these three genes are not involved in the cause of Sotos syndrome, or alternatively, mutations could not be identified in the small number of patients studied.
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Abstract
Extraordinary breakthroughs in the molecular pathogenesis of muscle and nerve disease have resulted in an evolving genetic classification of neuromuscular disorders and the development of new diagnostic methods. This remarkable progress has introduced new genetic tests and has changed the indications for use of certain invasive diagnostic procedures in the evaluation of children with presumed disorders of the motor unit. In this review, we present the current diagnostic approach to the more common neuromuscular diseases of infancy and childhood and define the diagnostic role of muscle biopsy and pediatric electromyography/nerve conduction studies in the era of genetic analysis.
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Menache CC, Brown CA, Donnelly JH, Shapiro F, Darras BT. Identification of a novel truncating mutation (S171X) in the Emerin gene in five members of a Caucasian American family with Emery-Dreifuss muscular dystrophy. Hum Mutat 2000; 16:94. [PMID: 10874323 DOI: 10.1002/1098-1004(200007)16:1<94::aid-humu27>3.0.co;2-n] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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