Endocrine disorders in septo-optic dysplasia (De Morsier syndrome)--evaluation and follow up of 18 patients

Neuroimaging Features in Children with Optic Nerve Hypoplasia and Septo-Optic-Pituitary Dysplasia

BACKGROUND

Optic nerve hypoplasia (ONH) and septo-optic-pituitary dysplasia (SOD) are common causes of congenital visual impairment. Our primary aim was to investigate the prevalence of abnormal neuroimaging features in patients with these disorders in Manitoba, Canada, and compare them with published reports.

METHODS

A retrospective neuroimaging review was performed in patients resident in Manitoba with ONH/SOD.

RESULTS

There were 128 patients (M = 70) with ONH/SOD who had neuroimaging. Their mean age (SD) at the end of the study was 13.2 (7.5) years. Males were significantly more likely to have bilateral ONH and a small optic chiasm size, while females were more likely to have a left ONH and a small left optic chiasm size on neuroimaging (p = 0.049). ONH and small optic chiasm size were seen in most patients on neuroimaging. Absent septum pellucidum was noted in 40%, small pituitary gland size in 28%, neuronal migration disorders (NMD) in 20% (>1 type and bilateral in 13 cases), corpus callosum abnormalities were present in 9%, while olfactory bulbs-tracts and olfactory sulci were absent in 8.6% of cases. Unilateral ONH was not significantly associated with other structural brain abnormalities, while NMD were significantly associated with other midline brain abnormalities including a symmetrically small optic chiasm size.

CONCLUSION

The prevalence of structural neuroimaging abnormalities in our cohort with ONH/SOD was generally in the same range reported in other studies with corpus callosum abnormalities being relatively less common in our study. Bilateral NMD were relatively common among patients with NMD. The association between sex and ONH laterality requires further study.

Patients with septo-optic dysplasia: General ophthalmologic assessment and retinal imaging

BACKGROUND

To evaluate the functional development and, retinal and optic disc morphology using OCT in patients with septo-optic dysplasia (SOD).

METHODS

This retrospective case series included patients diagnosed with SOD between 2007 and 2020. Ophthalmologic assessment included visual acuity (VA) and funduscopy at the initial and last presentation. Retinal imaging included OCT of the macula analyzing the retinal morphology, central retinal thickness volume (CRT) and ganglion cell layer (GCL). Also, scans of the optic nerve head were taken to evaluate the retinal nerve fiber layer (RNFL) and global value.

RESULTS

38 eyes of 19 children with a mean age 6.3 ± 5.3 years were included. 31.6% showed all 3 characteristics of SOD, whereof ONH, midline defects and endocrine dysfunctions were found in 94.7%, 89.5% and 47.4% respectively. The mean VA was 0.70 ± 0.66logMar in the right eye (RE) and 0.40 ± 0.55logMar in the left eye (LE) at the initial presentation. No change of vision (RE: 0.69 ± 0.71logMar; LE: 0.31 ± 0.57logMar) was found after a follow-up period of 6.3 ± 4.5years. Funduscopy showed an ONH in 79% (n = 30/38), tortuous retinal vessels in 36.8% (n = 14/38) and a double-ring sign in 15.8% (n = 6/38). Retinal imaging showed variable morphology. 6 eyes of 4 patients showed temporal retinal thinning with corresponding GCL attenuation. The optic nerve head appearance varied between no changes, sectoral and hemispherical reduction.

CONCLUSIONS

Patients suffering from SOD show diverse expression of retinal changes such as retinal, GCL and RNFL thinning in OCT. Furthermore, visual function remained stable during follow-up examinations, indicating no further alteration due to underlying pathology.

The Effects of Long-term Growth Hormone Treatment on Ocular Findings

PURPOSE

This study aimed to examine the long-term changes in anterior chamber depth (ACD), central corneal thickness (CCT), axial length (AxL), peripapillary retinal nerve fibre layer thickness (RNFLT), peripapillary ganglion cell layer - inner plexiform layer (GCL-IPL) thickness, and peripapillary choroidal thickness (ChT) after rhGH replacement treatment in paediatric patients with IGHD, compared to healthy controls.

METHODS

Twenty-two children with IGHD including 12 girls and 10 boys were enrolled in the study group, and 30 (16 girls, 14 boys) healthy children composed the control group. A detailed ophthalmological examination was performed for each participant. ACD, CCT, AxL, peripapillary RNFLT, GCL-IPL thickness and ChT measurements were performed before the rhGH replacement treatment and in the 12th month of the post-treatment period, as well as the corresponding visits in the control group. AxL ultrasound pachymetry (CCT), peripapillary RNFL thickness, peripapillary RNFLT, GCL-IPL thickness, and peripapillary ChT parameters were measured by spectral-domain optical coherence tomography.

RESULTS

The mean age of the groups were similar (p = 0.143). 12-month CCT, ACD, and AxL measurements of the study group showed significantly higher results than the pre-treatment measurements (p = 0.005, p = 0.024, and p = 0.002, respectively). Similarly, the mean RNFLT and ChT measurements of the study group obtained from all sectors were significantly higher in the 12th-month visit (p < 0.001 for both) other than the RNFLT, and GCL-IPL thickness measurements (p > 0.05 for all). However, all these parameters were similar at pre- and post-treatment visits in the control group (p > 0.05 for all). The mean pre-treatment values of all these parameters were significantly lower in the study group compared to the control group (p < 0.05 for all), other than the RNFLT, GCL-IPL thickness measurements (p > 0.05 for all), while the mean post-treatment values of all these parameters in both groups were similar at month 12 (p > 0.05 for all).

CONCLUSION

GH replacement treatment in childhood may play an important role in the development of the neural retina and can be effective on the anterior segment, RNFLT and ChT measurements.

Activating mutations in BRAF disrupt the hypothalamo-pituitary axis leading to hypopituitarism in mice and humans

Germline mutations in BRAF and other components of the MAPK pathway are associated with the congenital syndromes collectively known as RASopathies. Here, we report the association of Septo-Optic Dysplasia (SOD) including hypopituitarism and Cardio-Facio-Cutaneous (CFC) syndrome in patients harbouring mutations in BRAF. Phosphoproteomic analyses demonstrate that these genetic variants are gain-of-function mutations leading to activation of the MAPK pathway. Activation of the MAPK pathway by conditional expression of the BrafV600E/+ allele, or the knock-in BrafQ241R/+ allele (corresponding to the most frequent human CFC-causing mutation, BRAF p.Q257R), leads to abnormal cell lineage determination and terminal differentiation of hormone-producing cells, causing hypopituitarism. Expression of the BrafV600E/+ allele in embryonic pituitary progenitors leads to an increased expression of cell cycle inhibitors, cell growth arrest and apoptosis, but not tumour formation. Our findings show a critical role of BRAF in hypothalamo-pituitary-axis development both in mouse and human and implicate mutations found in RASopathies as a cause of endocrine deficiencies in humans.

Septo-optic dysplasia

Septo-optic dysplasia (SOD) or de Morsier's syndrome is a rare congenital disorder characterized by a classic triad of: (a) optic nerve hypoplasia, (b) agenesis of septum pellucidum and corpus callosum, and (c) hypoplasia of the hypothalamic-pituitary axis. This chapter will outline the key information regarding the etiology and epidemiology of this syndrome with a focus on its comprehensive management. Particular attention will be paid to the diagnostic stage and the most relevant differential diagnosis, before moving to the complexities of its treatment. In fact, although SOD is not curable, many aspects of this syndrome can be improved through a tailored multidisciplinary approach consisting in hormonal replacement, corrective ophthalmological surgery, management of epileptic seizures, and active neuropsychological support.

Review of the MRI brain findings of septo-optic dysplasia

AIM

To report the magnetic resonance imaging (MRI) findings from a retrospective case analysis of children with septo-optic dysplasia (SOD), a rare congenital disorder characterised by any combination of midline brain defects, optic nerve hypoplasia (ONH), and hypothalamic-pituitary dysfunction.

MATERIALS AND METHODS

SOD was defined radiologically as complete or partial septum pellucidum (SP) absence with hypoplasia of at least one of the optic nerves and/or chiasm. Local MRI databases were searched for SOD cases in children over an 18-year period, and studies reviewed by two consultant paediatric neuroradiologists. The extent of structural SP, optic nerve, chiasm, and hypothalamic-pituitary involvement was recorded, along with coexisting brain abnormalities.

RESULTS

Forty-eight cases of SOD were found; 44/48 (92%) demonstrated complete SP absence whereas 4/48 (8%) had partial absence. Eight of 48 cases (17%) exhibited unilateral ONH. Fifty-one percent of cases, where the pituitary was identified on MRI, demonstrated a structural pituitary abnormality, which included an ectopic posterior bright spot in 6%. The olfactory nerves were hypoplastic in 5/48 cases (10%). Twenty-seven of the 48 cases (56%) had another brain abnormality, resulting from some form of cortical formation abnormality/schizencephaly in 21/48 (44%).

CONCLUSION

A high rate of associated brain abnormalities was found in the present cohort, including structural pituitary abnormalities in 51% and cortical formation abnormalities/schizencephaly in 44%. This suggests there is not a single cause for SOD, rather SOD is the phenotypic end point from multiple aetiological events. Individual children with SOD may have coexisting intracranial abnormalities, and, hence, high-quality MRI is required in all.

Less known aspects of central hypothyroidism: Part 2 - Congenital etiologies

Central hypothyroidism (CH) occurs approximately in 1:50,000, and therefore is expected to be one thousand times rarer compared with primary hypothyroidism. Despite its rarity in the general population, it is much more common in certain disorders, in which it is frequently associated with other pituitary hormone deficiencies. The aim of this paper is to provide an updated review on the frequency of congenital CH, which is <1:50,000, and on its etiology, disregarding CH caused by other genetic defects, such as mutations of transcription factors involved in pituitary organogenesis or mutations of the genes encoding TRH or TRH receptor.

Reduced Hepatocellular Expression of Canalicular Transport Proteins in Infants with Neonatal Cholestasis and Congenital Hypopituitarism

OBJECTIVE

To assess whether prolonged neonatal cholestasis, described in congenital hypopituitarism and septo-optic dysplasia (SOD), is associated with altered expression of selected canalicular ectoenzymes and canalicular transport proteins.

STUDY DESIGN

Children with congenital hypopituitarism (n = 21), SOD (n = 18), and cholestasis seen in our center over 26 years were reviewed. Histopathologic findings in archival liver biopsy specimens were assessed (n = 10) and in those with low/normal levels of serum γ-glutamyltransferase (GGT) activity despite conjugated hyperbilirubinemia, expression of canalicular ectoenzymes and canalicular transport proteins was evaluated immunohistochemically.

RESULTS

Patients presented at a median age of 8 weeks (range 3-20 weeks) with median total bilirubin 116 µmol/L (45-287 µmol/L), GGT 95 IU/L (25-707 UI/L), and serum cortisol 51 nmol/L (17-240 nmol/L). All but 3 had low free thyroxin (median 9.6 pmol/L [6.8-26.9]) with increased thyroid-stimulating hormone levels (median 5.95 mU/L [<0.1-9.24]). Liver histologic features included moderate-to-severe intralobular cholestasis with nonspecific hepatitis, giant-cell transformation of hepatocytes, and fibrosis. In all, immunohistochemical staining for canalicular ectoenzymes and canalicular transport proteins revealed a degree of reduced expression, associated with normal serum GGT values in 6 of the 10 patients, and another 6 nonbiopsied infants with cholestasis also had low/normal serum GGT activity. Sequencing of ABCB11 and ATP8B1 performed in 6 of the biopsied patients did not identify pathogenic mutations. Following replacement therapy, biochemical evidence of hepatobiliary injury resolved in all children within a median period of 6 months.

CONCLUSION

Hepatobiliary involvement in congenital hypopituitarism associated with SOD has a good prognosis, but its etiology remains uncertain. Immunohistochemical expression of canalicular transport proteins was reduced in available liver samples.

Novel FOXA2 mutation causes Hyperinsulinism, Hypopituitarism with Craniofacial and Endoderm-derived organ abnormalities

Congenital hypopituitarism (CH) is characterized by the deficiency of one or more pituitary hormones and can present alone or in association with complex disorders. Congenital hyperinsulinism (CHI) is a disorder of unregulated insulin secretion despite hypoglycaemia that can occur in isolation or as part of a wider syndrome. Molecular diagnosis is unknown in many cases of CH and CHI. The underlying genetic etiology causing the complex phenotype of CH and CHI is unknown. In this study, we identified a de novo heterozygous mutation in the developmental transcription factor, forkhead box A2, FOXA2 (c.505T>C, p.S169P) in a child with CHI and CH with craniofacial dysmorphic features, choroidal coloboma and endoderm-derived organ malformations in liver, lung and gastrointestinal tract by whole exome sequencing. The mutation is at a highly conserved residue within the DNA binding domain. We demonstrated strong expression of Foxa2 mRNA in the developing hypothalamus, pituitary, pancreas, lungs and oesophagus of mouse embryos using in situ hybridization. Expression profiling on human embryos by immunohistochemistry showed strong expression of hFOXA2 in the neural tube, third ventricle, diencephalon and pancreas. Transient transfection of HEK293T cells with Wt (Wild type) hFOXA2 or mutant hFOXA2 showed an impairment in transcriptional reporter activity by the mutant hFOXA2. Further analyses using western blot assays showed that the FOXA2 p.(S169P) variant is pathogenic resulting in lower expression levels when compared with Wt hFOXA2. Our results show, for the first time, the causative role of FOXA2 in a complex congenital syndrome with hypopituitarism, hyperinsulinism and endoderm-derived organ abnormalities.

Increased Intraocular Pressure in a Patient With Septooptic Dysplasia: A Case Report

INTRODUCTION

Previous studies have described septooptic dysplasia (SOD) to describe patients who have optic nerve hypoplasia, the absence of septum pellucidum, and pituitary hypoplasia. Other rare ophthalmic associations have been described, such as low-tension glaucoma. We report the ocular findings of a patient with SOD who had high intraocular pressure (IOP) and glaucoma as a part of the syndrome.

OBJECTIVES

To report the ocular findings in a Puerto Rican patient with SOD and increased IOP.

PATIENTS AND METHODS

A patient with De Morsier syndrome underwent a comprehensive eye examination, Humphrey visual fields, and Stratus optical coherence tomography, and was referred for neuroradiologic examination. The patient had increased IOP, visual field loss, and asymmetric optic nerve hypoplasia. The IOP was lowered with topical hypotensive medications.

CONCLUSIONS

The patient with the De Morsier syndrome had poor visual acuity, high IOP, visual field, and optical coherence tomography results that were all compatible with glaucoma. Further studies comparing ocular findings in patients with several mutations leading to De Morsier syndrome are warranted. To our knowledge, this is the first report on a patient with glaucoma as a part of the syndrome.

Spectrum of clinical presentations and endocrinological findings of patients with septo-optic dysplasia: a retrospective study

BACKGROUND

Septo-optic dysplasia (SOD) is a rare condition with variable clinical pictures and spectrum of findings.

OBJECTIVE

To analyze the spectrum of findings, frequency and age of onset of hypothalamic-pituitary dysfunctions in children with SOD.

METHOD

A retrospective electronic medical record (EMR) chart review was done for patients with SOD seen in a tertiary care center's pediatric endocrinology clinic between January 1, 2012, and March 31, 2014. The diagnostic criteria for SOD included presence of ≥ 2 of the following: (i) optic nerve hypoplasia, (ii) agenesis/hypoplasia of septum pellucidum and/or corpus callosum and (iii) hypothalamic-pituitary dysfunction.

RESULTS

Eighty patients fitting the diagnostic criteria of SOD were included in this study. The majority of patients (96%) had optic nerve hypoplasia on magnetic resonance imaging and were diagnosed due to visual issues including nystagmus (36%) or strabismus (13.8%). Hypothalamic-pituitary dysfunction was most common (51%) when optic nerve hypoplasia was present with (36%) or without (15%) dysgenesis of septum pellucidum and/or corpus callosum compared to dysgenesis of septum pellucidum and/or corpus callosum alone (4%). Hypothalamic-pituitary dysfunction was noted in 55% of patients, and most (86%) were diagnosed ≤ 2 years of age. Central hypothyroidism and growth hormone deficiency were most common followed by secondary/tertiary adrenal insufficiency and diabetes insipidus.

CONCLUSIONS

The risk of hypothalamic-pituitary dysfunction in SOD is highest ≤ 2 years of age and when both optic nerve hypoplasia and dysgenesis of septum pellucidum/corpus callosum are present, suggesting a need for more frequent follow-up and screening tests for hypothalamic-pituitary dysfunction in these patients.

Corneal thickness in children with growth hormone deficiency: the effect of GH treatment

OBJECTIVE

The eye represents a target site for GH action, although few data are available in patients with GH deficiency (GHD). Our aim was to evaluate central corneal thickness (CCT) and intraocular pressure (IOP) values in GHD children to assess the role played by GHD or GH treatment on these parameters.

DESIGN

In 74 prepubertal GHD children (51M, 23F, aged 10.4±2.4years) we measured CCT and IOP before and after 12months of treatment. A baseline evaluation was also made in 50 healthy children matched for age, gender and body mass index. The study outcome considered CCT and IOP during treatment and their correlations with biochemical and auxological data.

RESULTS

No difference in CCT and IOP between GHD children at baseline and controls was found (all p>0.005). GHD children after 12months of therapy showed greater CCT (564.7±13.1μm) than both baseline values (535.7±17μm; p<0.001) and control subjects (536.2±12.5μm; p<0.001), with a concomitantly higher corrected mean IOP (15.6±0.7mmHg; p<0.001) than both baseline (12.5±0.8mmHg; p<0.001) and controls (12.3±0.5mmHg; p<0.001), without correlation with auxological and biochemical parameters.

CONCLUSIONS

12months of GH treatment in children with GHD, regardless of auxological and biochemical data, affect CCT and IOP. Our findings suggest careful ocular evaluation in these patients to prevent undesirable side effects during the follow-up.

Pediatric outcome of children with the prenatal diagnosis of isolated septal agenesis

BACKGROUND

Isolated Septal Agenesis (SA) is a rare disease with clinical outcomes (especially neurological outcomes) that are unknown. The purpose of this study was to evaluate the clinical outcome of these children.

METHODS

We conducted a retrospective multicenter study of 17 children with an isolated SA or SA combined with a moderate ventricular dilatation (VD) that was diagnosed antenatally and confirmed by a magnetic resonance imaging (MRI) performed in the antenatal period.

RESULTS

Of the 17 children, 14 had normal neurological examinations, 2 had language development delay and visuo-spatial dyspraxia, and 3 of the 17 children had behavioral problems. Eight children had neuropsychological evaluations, and the results were normal in six cases. There were 3 cases of septo-optic dysplasia (SOD) diagnosed postnatally, which highlighted the difficulties in assessing the optic tract and hypothalamic-pituitary region in antenatal imaging. Language delay and behavioral disorders were the main abnormalities at follow-up.

CONCLUSION

The discovery of an isolated SA reveals the difficulties of prenatal diagnosis to correlate the neurological and functional prognosis to morphological findings. The prognosis seemed to be good. It appears necessary to improve the diagnostic performance of fetal brain imaging and to follow-up these children prospectively to assess their long-term cognitive-behavioral outcomes.

Absence of the septum pellucidum associated with a midline fornical nodule and ventriculomegaly: a report of two cases

We report two autopsy cases that revealed the partial absence of the septum pellucidum with ventriculomegaly. In each case, the brain showed mild dilatation of both frontal horns of the lateral ventricles, normal third and fourth ventricles and no aqueductal stenosis. The posterior portion of the septum pellucidum was absent and the fornices were fused in a single midline nodule, abnormally displaced to a caudal position and lodged in the foramina of Monro. The brain base showed no apparent abnormalities; the optic nerves were well developed. We conclude that the caudally displaced fornix in the absence of the septum pellucidum may have intermittently obstructed the foramina of Monro and induced mild ventriculomegaly.

Severe hypernatraemia associated with growth hormone replacement therapy in a patient with septo-optic dysplasia

BACKGROUND

The anti-natriuretic properties of growth hormone (GH) are well established. Growth hormone deficiency (GHD) results in salt and water depletion and studies confirm that replacement leads to sodium and vasopressin-mediated water retention in patients with intact posterior pituitary function.

METHODS

We report the case of a 20-year-old male patient with septo-optic dysplasia, fixed cranial diabetes insipidus (DI) and an abnormal thirst threshold. With careful parental support, his sodium levels remained stable for many years on a fixed dose of DDAVP and a supervised fluid intake of 2.5 l/day. Several years after the original diagnosis, he was found to be ACTH deficient and following commencement of hydrocortisone replacement therapy became hypernatraemic. A new sodium homoeostasis was established with a higher dose of DDAVP. Subsequently, he developed symptoms typical of GHD and, after biochemical confirmation, GH replacement was commenced.

RESULTS

There was an immediate clinical improvement (increased alertness, improved concentration) but severe hypernatraemia developed (peak 169 mmol/l) necessitating revision of his desmopressin and fluid intake regimen.

CONCLUSION

Most GHD patients have intact posterior pituitary function. This case report highlights the powerful anti-natriuretic properties of GH. Endocrine physicians should be alert to this in patients with fixed DI and an abnormal thirst threshold.

Disorders of prosencephalic development

Abnormal ventral induction may result in disorders of formation, cleavage, and midline development of prosencephalic structures. Holoprosencephaly is a developmental field defect of impaired cleavage of prosencephalon. The most widely accepted classification of holoprosencephaly recognizes three major varieties: the alobar, semilobar and lobar types, according to the severity of the malformation. The brain malformations, characterized by the fusion of the cerebral hemisphere along the midline are commonly associated with facial anomalies. Corpus callosum agenesis and septo-optic dysplasia are disorders of prosencephalic midline development, and usually have less severe presentations but still, affected subjects may suffer from neurodevelopmental retardation, and/or endocrinologic and visual disorders. In this article we report an up-to-date of pathogenesis, prenatal sonographic findings, differential diagnosis and prognosis of the aforementioned anomalies.

Septo-optic dysplasia - novel insights into the aetiology

Septo-optic dysplasia (SOD) is a highly heterogeneous condition comprising a variable phenotype of optic nerve hypoplasia, midline brain abnormalities and pituitary hypoplasia with consequent endocrine deficits. The majority of cases are sporadic and several aetiologies have been suggested to account for the pathogenesis of the condition. However, a number of familial cases have been described and the identification of mutations in key developmental genes including HESX1, SOX2 and SOX3 in patients with SOD and associated phenotypes suggests that a genetic causation is likely in the more common sporadic cases of the condition. The precise aetiology of SOD is most likely multifactorial involving contributions from environmental factors in addition to an important role for crucial developmental genes. The variability of the penetrance and phenotypes within a single SOD pedigree may also suggest a complex interaction between genetics and the environment, and at present, the understanding of these interactions is rudimentary. Further study of these critical factors may shed light on the aetiology of this complex disorder. We have reviewed recent literature selecting relevant references based on the keywords HESX1, SOX2, SOX3, Septo-optic dysplasia, genetics and pituitary development.

Growth hormone in the visual system: comparative endocrinology

Growth hormone (GH) is rarely considered to be involved in ocular development or vision or to be present in the visual system. Basic and clinical studies nevertheless support roles for GH in the ocular function of most vertebrate groups and for its extrapituitary production in ocular tissues. The comparative endocrinology of endocrine, autocrine or paracrine GH in the visual system of vertebrates is the focus of this brief review.

Genetics of septo-optic dysplasia

Septo-optic dysplasia (SOD) is a highly heterogeneous condition comprising a variable phenotype of optic nerve hypoplasia, midline forebrain abnormalities and pituitary hypoplasia with consequent endocrine deficits. The majority of cases are sporadic and several aetiologies including drug and alcohol abuse have been suggested to account for the pathogenesis of the condition. However, a number of familial cases have been described and the identification of mutations in the key developmental gene HESX1 in patients with SOD and associated phenotypes suggests that a genetic causation is likely in the more common sporadic cases of the condition. More recently, we have implicated duplications of SOX3 and mutations of both SOX2 and SOX3 in the aetiology of variants of SOD. As with other developmental disorders such as holoprosencephaly, the precise aetiology is most likely multifactorial involving contributions from environmental factors in addition to an important role for crucial developmental genes. This potentially complex interaction between genetics and the environment is borne out by the variability of the penetrance and phenotypes in patients with genetic SOD, but at present, the understanding of these interactions is rudimentary. Further study of these critical factors may shed light on the aetiology of this complex disorder.

Optic nerve hypoplasia and growth hormone deficiency in a cholestatic infant

This report describes a 4-month-old male with cholestasis, hypoglycemia, and short stature. Symptoms appeared since neonatal age with jaundice, hypoglycemia, neurologic manifestations, and later with short stature. Laboratory investigation was indicative for cholestasis. Further research indicated isolated growth hormone deficiency with accompanying optic nerve hypoplasia. Unexplained hypoglycemia and cholestasis in neonates have to be investigated for growth hormone deficiency. Moreover, in cases with unexplained cholestasis, timely recognition of hypoglycemia is important for the early diagnosis of the disorder before the appearance of growth retardation.

Prenatal diagnosis of septal agenesis with normal pituitary function

Septal agenesis is a rare brain malformation that is characterized by partial or complete absence of the septum pellucidum, either isolated or associated with other brain anomalies. We report a case presenting with septal agenesis and normal optic chiasm and pituitary function in a fetus at 19 weeks of gestation.

Hypopituitarism and neurodevelopmental abnormalities in relation to central nervous system structural defects in children with optic nerve hypoplasia

OBJECTIVE

Optic nerve hypoplasia (ONH) is a heterogeneous disease with variable findings of pituitary insufficiency, CNS and neurodevelopmental abnormalities. We characterized the spectrum of endocrinopathy in a cohort of children with ONH and attempted to correlate the presence of different midline CNS findings with the degree of hypopituitarism. The correlation of variable CNS abnormalities with the presence of a seizure disorder and neurodevelopmental delay was also examined.

METHODS

Charts of 56 patients with ONH referred to our endocrine clinics between 1990 and 2000 were reviewed. Neurodevelopmental assessment was based on questionnaires sent to families during the study period.

RESULTS

Forty-six patients (82%) had hypopituitarism, with growth hormone deficiency being the most common endocrinopathy. All patients with diabetes insipidus, hypocortisolism, and hypogonadotropin hypogonadism also had combined pituitary hormone deficiency. Evolving pituitary hormone deficiency was observed in two of 37 patients diagnosed with hypopituitarism in the first 3 years of life. No single midline CNS finding correlated with the presence of hypopituitarism or a seizure disorder. However, hydrocephalus or a seizure disorder was more commonly seen in patients with developmental delay.

CONCLUSION

ONH is a heterogeneous disorder with possible multifactorial etiologies. All patients with this diagnosis deserve a comprehensive endocrine and neurodevelopmental evaluation.

Prenatal diagnosis of absence of the septum pellucidum associated with septo-optic dysplasia

Septo-optic dysplasia (SOD; De Morsier syndrome) is a rare congenital disorder characterized by the absence of the septum pellucidum (SP), hypoplasia of the optic chiasma and nerves, and various types of hypothalamic-pituitary dysfunction. We report on two fetuses with absence of the SP diagnosed by ultrasound examination at 29 and 30 gestational weeks. In the first case the diagnosis of SOD was suspected in utero and confirmed postnatally; to the best of our knowledge this is the first report of the prenatal diagnosis of SOD. In the second case absence of the SP appeared to be isolated and no visual or endocrine impairment were detected after birth.

Septo-optic dysplasia with digital anomalies?a recurrent pattern syndrome

A distinct form of septo-optic dysplasia (SOD) comprises limb malformations in addition to the characteristic CNS and ocular abnormalities. To date, there have been 4 reports, citing 5 affected patients with this combined phenotype. We now add a further case and present neuroradiological images of the CNS findings in this condition. The striking consistency of the limb malformations and their overlap with the Streeter's band phenotype is emphasized.

Congenital disorders of the optic nerve: excavations and hypoplasia

The principal congenital abnormalities of the optic disc that can significantly impair visual function are excavation of the optic disc and optic nerve hypoplasia. The excavated optic disc abnormalities comprise optic disc coloboma, morning glory syndrome, and peripapillary staphyloma. Optic nerve hypoplasia manifests as a small optic nerve, which may or may not be accompanied by a peripapillary ring (the double ring sign). In addition, the optic disc cupping, which occurs as a sequel to some cases of periventricular leucomalacia, can arguably be classified as a type of optic nerve hypoplasia. All of these conditions can be unilateral or bilateral and can impair visual function mildly or severely. It is essential that children with poor vision due to any of these conditions are managed by treating refractive errors, giving occlusion therapy in selected cases, and optimising the conditions at home and at school in an attempt to ensure that impaired vision does not impede development or education.

Growth hormone deficiency (GHD): A new association in Peters' plus syndrome (PPS)

We report a case of a girl with clinical features of Peters' Plus Syndrome (PPS) (association of anterior eye chamber defects; peculiar facies; cleft lip/palate; brachymelia; developmental delay; growth retardation) and documented growth hormone deficiency (height -3.5 SDS at chronological age 5 years 8 months; low growth factors; bone age delay; growth velocity 4.4 cm/year (<3rd centile); and peak growth hormone levels of 1.7 and 4.7 ng/ml by clonidine and insulin provocative testing, respectively). Treatment with recombinant human growth hormone (0.3 mg/kg/week) resulted in a dramatic increase in growth velocity, increasing the height from -3.5 to -1.5 SDS over 2.3 years of therapy, indicative of an excellent response. Growth retardation is a known association in PPS: a condition that includes other midline facial defects. This case supports a role for GHD in the pathogenesis of the short stature observed in these children; demonstrates the efficacy of GH treatment; and further reinforces the relationship of pituitary anomalies with common congenital defects.

Septo-optic dysplasia with congenital hepatic fibrosis

This article reports a 7-year-old female with septo-optic dysplasia and congenital hepatic fibrosis. She manifested nystagmus and severe hepatosplenomegaly. Brain magnetic resonance imaging revealed agenesis of the septum pellucidum, optic nerve hypoplasia, pituitary gland stalk hypoplasia, and absence of the posterior pituitary gland. She was diagnosed with growth hormone deficiency, hypothyroidism, diabetes insipidus, and adrenal insufficiency. Thus, this case was regarded as septo-optic dysplasia. No mutation was evident in the coding and boundary regions of the homeobox gene HESX1. Percutaneous biopsy of the liver demonstrated the presence of broad septa of fibrous tissue containing abundant bile ducts without inflammatory cell infiltrates, a finding compatible with congenital hepatic fibrosis. Although there is an association between septo-optic dysplasia and neonatal cholestasis, believed to be related to hypopituitarism, this case of septo-optic dysplasia with congenital hepatic fibrosis is apparently the first reported in the English literature.

Visually impaired children with posterior ocular malformations: pre- and neonatal data and visual functions

AIM

To analyse pre- and neonatal data and ocular findings in children with visual impairment caused by posterior ocular malformations.

METHODS

Medical records were scrutinized, dried blood spot cards were analysed for virus DNA and ophthalmological assessments were performed in 28 children with optic nerve hypoplasia (ONH) and 10 with optic/chorio-retinal coloboma.

RESULTS

Prenatal exposure to possible teratogens was documented in 5/28, herpes simplex virus type 1 DNA was identified in the dried blood spot cards of 1/26 children and neonatal hypoglycaemia in 12/28 children with ONH. The time delay from ocular to endocrinological diagnosis and treatment was 3 years. Children with ONH and severe visual impairment had endocrinopathy more often (11/13) than ONH children with better visual functions (5/15). Prenatal exposure to teratogens or neonatal hypoglycaemia was not identified in any of the children with coloboma.

CONCLUSION

Neonatal hypoglycaemia was common in children with ONH. Severe visual impairment predicted endocrinopathy. Analysis of dried blood spot cards could serve as an additional diagnostic tool in children with ocular malformations.

Optic nerve hypoplasia in cholestatic infants: a multiple case study

PURPOSE

To present four infants with optic nerve hypoplasia and cholestasis.

METHODS

All patients underwent detailed ophthalmological and hepatological assessment. Their endocrinological and neuroradiological examinations were re-evaluated.

RESULTS

All four infants presented with cholestasis and were subsequently found to have optic nerve hypoplasia. One child was blind according to the WHO definition and two had low vision. The fourth child had unilateral optic nerve hypoplasia and was too young to be assessed with optotypes. All four children had central nervous system and/or endocrine dysfunction. However, only one child had septo-optic dysplasia. The longterm outcome of liver disease seemed favourable in all children.

CONCLUSION

Early assessment by a paediatric ophthalmologist as well as a multidisciplinary approach is of great importance in cholestatic infants.

Septo-optic dysplasia/optic nerve hypoplasia: data from the National Cooperative Growth Study (NCGS)

We analyzed data from 65 children with septo-optic dysplasia (SOD) referred for evaluation and followed in the National Cooperative Growth Study (NCGS) Substudy 8 and from 758 children treated with growth hormone (GH) and followed in the NCGS core study. Compared to other children referred for evaluation of short stature, children with SOD were younger (mean age 3.7 +/- 3.6 vs 8.6 +/- 4.9 years), had less severe short stature (mean +/- SD height SDS -1.80 +/- 1.64 vs -2.17 +/- 0.95), and were more likely to be female (46% F vs 31% M). Children with SOD who received GH were older and shorter than those referred and untreated, but the gender distribution was similar. Other pituitary hormone deficits were reported in untreated patients, including thyroid hormone deficiencies (8%) and adrenocorticotropic hormone (ACTH) deficiency (3%), as compared to 27% and 24%, respectively, in GH-treated children. Data on adult height were available for 71 patients, who showed an average gain in height SDS of 1.17 +/- 1.49. GH therapy was well tolerated in children with SOD.

A case of growth hormone and gonadotropin deficiency associated with unilateral anophthalmia, microphallus, cryptorchidism, and mental retardation

We report a rare case of growth hormone and gonadotropin deficiency associated with dysmorphic features. A 16-year-old boy had left anophthalmia, microphallus, bilateral cryptorchidism, and mental retardation. His chromosomal karyotype was normal, 46, XY. Endocrinological studies revealed growth hormone and gonadotropin deficiency, attributed to hypothalamic dysfunction. Magnetic resonance imaging scan of the head showed a hypoplastic pituitary gland, decreased high intensity signals in the pituitary posterior lobe, absence of the left eye, and a hypoplastic left optic nerve with no abnormality of the pituitary stalk, corpus callosum, or septum pellucidum. Although not completely consistent with the features of septo-optic dysplasia (SOD), his condition was considered within the spectrum of SOD. Despite similarities to the Hesx1 knockout mouse, a model of human SOD, mutation analyses revealed no mutations or polymorphisms in coding regions of any exons or intron-exon boundaries of the HESX1 gene. Further genetic studies of this patient may improve understanding of molecular mechanisms involved in pituitary development.

Neuropathologic research strategies in holoprosencephaly

Hypotheses are presented to explain the pathogenesis of several clinical features of holoprosencephaly, and neuropathologic approaches to testing these hypotheses are suggested. The traditional morphologic classification of holoprosencephaly into alobar, semilobar, and lobar forms is grades of severity, and each occurs in all of the genetic mutations known. Of the four defective genes identified as primary in human holoprosencephaly, three exhibit a ventrodorsal gradient of expression (SHH, SIX3, and TGIF) and one a dorsoventral gradient (ZIC2). But, in addition to the vertical axis, genes expressed in the neural tube also may have rostrocaudal and mediolateral gradients in the other axes. These other gradients may be equally as important as the vertical. If the rostrocaudal gradient extends as far as the mesencephalic neuromere, it may interfere with the formation, migration, or apoptosis of the mesencephalic neural crest, which forms membranous bones of the face, orbits, nose, and parts of the eyes, and may explain the midfacial hypoplasia seen in many, but not all, children with holoprosencephaly. This rostrocaudal gradient also causes noncleavage of the caudate nucleus, thalamus, and hypothalamus and contributes to the formation of the dorsal cyst of holoprosencephaly, which is probably derived from an expanded suprapineal recess of the 3rd ventricle with secondary dilation of the telencephalic monoventricle and at times may produce a unique transfontanellar encephalocele. The extent of the mediolateral gradient may explain the severe disorganization of cerebral cortical architecture in medial parts of the forebrain and normal cortex in lateral parts, including the radial glial fibers. This preserved lateral cortex may explain why some children with holoprosencephaly have better intellectual function than expected and may also be important in the pathogenesis of epilepsy, by contrast with malformations such as lissencephaly, in which the entire cerebral cortex is involved. Epilepsy in some, but not all, cases also may be related to the sequential maturation of axonal terminals in relation to the neurons they innervate. Diabetes insipidus is a complication in a majority of patients; other neuroendocrinopathies occur less frequently. Secondary down-regulation of the OTP gene or of downstream genes such as BRN2 or SIM1 may result in failure of terminal differentiation of magnocellular neurons of the supraoptic and paraventricular hypothalamic nuclei. Disoriented radial glial fibers or abnormal ependyma may allow aberrant migration of neuroepithelial cells into the ventricle. A new classification of holoprosencephaly is needed to integrate morphologic and genetic criteria.

The pituitary gland: embryology, physiology, and pathophysiology

The pituitary gland, the "master gland" of the body, is composed of endocrine cells, which secrete hormones essential for homeostasis. The gland consists of the adenohypophysis (anterior pituitary) and the neurohypophysis (posterior pituitary), two unique structures that differ anatomically and functionally. The neurohypophysis is innervated by nerve cells in the hypothalamus and forms the connection between it and the pituitary gland. The hypothalamus stimulates release and inhibition of pituitary hormones. The neurohypophysis secretes oxytocin and antidiuretic hormone. The adenohypophysis is composed of three structures: the pars distalis, the pars intermedia, and the pars tuberalis. The anterior pituitary (pars distalis) is responsible for the release of hormones that include growth hormone, prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, adrenocorticotropic hormone, and melanocyte-stimulating hormone. Disorders of the pituitary are predominately those of insufficient hormone release and may have profound effects on the neonate. The potential causes of and clinical symptomatology that may accompany pituitary hormone insufficiency in the neonatal period are explored.

Blepharoptosis and central nervous system abnormalities in combined valproate and hydantoin embryopathy

PURPOSE

To report a case of intrauterine anticonvulsant exposure with subsequent ocular adnexal manifestations.

METHODS

Case report.

RESULTS

An 18-month-old child with known anticonvulsant embryopathy was referred for the management of bilateral congenital blepharoptosis. Physical examination confirmed ocular and nonocular external manifestations of valproate and hydantoin embryopathies. Cavum septum pellucidum, mild sulcation defects, and cerebellar atrophy were identified on neuroimaging.

CONCLUSIONS

To our knowledge, our patient represents the second reported case of anomalous septum pellucidum after intrauterine valproate exposure. Clinicians evaluating patients with craniofacial features associated with intrauterine valproate exposure should recognize that concomitant anomalies of the central nervous system, including the septum pellucidum, might exist.

Hypothalamic Peptides in Human Brain Diseases

The human hypothalamus is subdivided into some 20 well-defined nuclei that have a multitude of specific functions from the time of birth to the moment we die. Hypothalamic nuclei show structural and functional differences not only in relation to classic neuroendocrine disorders, such as diabetes insipidus, climacteric flushes and Kallman's syndrome, but also in relation to gender and sexual orientation, to adaptive processes such as non-thyroidal illness and in psychiatric disorders such as depression.

Prader-Willi syndrome and the hypothalamus

Dysfunction of various hypothalamic systems may be the basis of a number of symptoms in Prader-Willi syndrome. The often abnormal position of the baby in the uterus at the onset of labour, the high percentage of infants with asphyxia and the high proportion of children born prematurely or post-maturely may all be related to abnormal fetal hypothalamic systems, as the fetal hypothalamus plays a crucial role in labour. Abnormal luteinizing hormone-releasing hormone neurones are thought to be responsible for the decreased levels of sex hormones, resulting in non-descended testes, undersized sex organs and insufficient growth during puberty. A lack of growth hormone-releasing hormone may also contribute to the short stature of patients with Prader-Willi syndrome. In addition, the aberrant control of body temperature and daytime hypersomnolence may result from hypothalamic disturbances. The number of oxytocin neurones--the putative satiety neurones--in the hypothalamic paraventricular nucleus is markedly decreased in Prader-Willi syndrome. This is presumed to be the basis of the insatiable hunger and obesity of patients with the syndrome.