Hydrocephaly, congenital retinal nonattachment, and congenital falciform fold

Clinical and Molecular Spectrum of Muscular Dystrophies (MDs) with Intellectual Disability (ID): a Comprehensive Overview

Muscular dystrophies encompass a wide and heterogeneous subset of hereditary myopathies that manifest by the structural or functional abnormalities in the skeletal muscle. Some pathogenic mutations induce a dysfunction or loss of proteins that are critical for the stability of muscle cells, leading to progressive muscle degradation and weakening. Several studies have well-established cognitive deficits in muscular dystrophies which are mainly due to the disruption of brain-specific expression of affected muscle proteins. We provide a comprehensive overview of the types of muscular dystrophies that are accompanied by intellectual disability by detailed consulting of the main libraries. The current paper focuses on the clinical and molecular evidence about Duchenne, congenital, limb-girdle, and facioscapulohumeral muscular dystrophies as well as myotonic dystrophies. Because these syndromes impose a heavy burden of psychological and financial problems on patients, their families, and the health care community, a thorough examination is necessary to perform timely psychological and medical interventions and thus improve the quality of life.

A Successful Treatment of Endoscopic Third Ventriculostomy with Choroid Plexus Cauterization for Hydrocephalus in Walker-Warburg Syndrome

Walker-Warburg syndrome (WWS) is a rare autosomal recessive congenital muscular dystrophy with brain malformations and ocular abnormalities that falls under the wider phenotypic spectrum of the dystroglycanopathies. Mutations in a number of genes including POMT1, POMT2, POMGNT1, POMGNT2, FKTN, FKRP, LARGE, and ISPD are known to cause alpha dystroglycan-related muscular dystrophy. Mutations in these genes result in a broad phenotypic spectrum ranging from the severe WWS to a mild congenital muscular dystrophy with no brain involvement. WWS is fatal to most patients early in life with mean survival of 9 months. The most common brain finding is cobblestone lissencephaly with the vast majority of patients (97%) also having ventricular dilation with or without hydrocephalus. Surgical treatment has not been frequently detailed. This report describes our successful treatment of a patient with WWS and hydrocephalus with Endoscopic Third Ventriculostomy (ETV) with choroid plexus cauterization (CPC). Fourteen months following treatment, a follow-up MRI CSF flow study demonstrated robust CSF flow through floor of third ventricle from interpeduncular cistern to lateral ventricle.

Congenital muscular dystrophy: from muscle to brain

Congenital muscular dystrophies (CMDs) are a wide group of muscular disorders that manifest with very early onset of muscular weakness, sometime associated to severe brain involvement.The histologic pattern of muscle anomalies is typical of dystrophic lesions but quite variable depending on the different stages and on the severity of the disorder.Recent classification of CMDs have been reported most of which based on the combination of clinical, biochemical, molecular and genetic findings, but genotype/phenotype correlation are in constant progression due to more diffuse utilization of the molecular analysis.In this article, the Authors report on CMDs belonging to the group of dystroglycanopathies and in particular on the most severe forms represented by the Fukuyama CMD, Muscle-Eye-Brain disease and Walker Walburg syndrome.Clinical diagnosis of infantile hypotonia is particularly difficult considering the different etiologic factors causing the lesions, the difficulty in localizing the involved CNS area (central vs. peripheral) and the limited role of the diagnostic procedures at this early age.The diagnostic evaluation is not easy mainly in differentiating the various types of CMDs, and represents a challenge for the neonatologists and pediatricians. Suggestions are reported on the way to reach a correct diagnosis with the appropriate use of the diagnostic means.

Mechanistic aspects of the formation of α-dystroglycan and therapeutic research for the treatment of α-dystroglycanopathy: A review

α-Dystroglycanopathy, an autosomal recessive disease, is associated with the development of a variety of diseases, including muscular dystrophy. In humans, α-dystroglycanopathy includes various types of congenital muscular dystrophy such as Fukuyama type congenital muscular dystrophy (FCMD), muscle eye brain disease (MEB), and the Walker Warburg syndrome (WWS), and types of limb girdle muscular dystrophy 2I (LGMD2I). α-Dystroglycanopathy share a common etiology, since it is invariably caused by gene mutations that are associated with the O-mannose glycosylation pathway of α-dystroglycan (α-DG). α-DG is a central member of the dystrophin glycoprotein complex (DGC) family in peripheral membranes, and the proper glycosylation of α-DG is essential for it to bind to extracellular matrix proteins, such as laminin, to cell components. The disruption of this ligand-binding is thought to result in damage to cell membrane integration, leading to the development of muscular dystrophy. Clinical manifestations of α-dystroglycanopathy frequently include mild to severe alterations in the central nervous system and optical manifestations in addition to muscular dystrophy. Eighteen causative genes for α-dystroglycanopathy have been identified to date, and it is likely that more will be reported in the near future. These findings have stimulated extensive and energetic investigations in this research field, and novel glycosylation pathways have been implicated in the process. At the same time, the use of gene therapy, antisense therapy, and enzymatic supplementation have been evaluated as therapeutic possibilities for some types of α-dystroglycanopathy. Here we review the molecular and clinical findings associated with α-dystroglycanopathy and the development of therapeutic approaches, by comparing the approaches with the development of Duchenne muscular dystrophy.

Metabolic causes of epileptic encephalopathy

Epileptic encephalopathy can be induced by inborn metabolic defects that may be rare individually but in aggregate represent a substantial clinical portion of child neurology. These may present with various epilepsy phenotypes including refractory neonatal seizures, early myoclonic encephalopathy, early infantile epileptic encephalopathy, infantile spasms, and generalized epilepsies which in particular include myoclonic seizures. There are varying degrees of treatability, but the outcome if untreated can often be catastrophic. The importance of early recognition cannot be overemphasized. This paper provides an overview of inborn metabolic errors associated with persistent brain disturbances due to highly active clinical or electrographic ictal activity. Selected diseases are organized by the defective molecule or mechanism and categorized as small molecule disorders (involving amino and organic acids, fatty acids, neurotransmitters, urea cycle, vitamers and cofactors, and mitochondria) and large molecule disorders (including lysosomal storage disorders, peroxisomal disorders, glycosylation disorders, and leukodystrophies). Details including key clinical features, salient electrophysiological and neuroradiological findings, biochemical findings, and treatment options are summarized for prominent disorders in each category.

Increased apoptosis of myoblasts in Drosophila model for the Walker-Warburg syndrome

Walker-Warburg syndrome, a progressive muscular dystrophy, is a severe disease with various kinds of symptoms such as muscle weakness and occasional seizures. The genes of protein O-mannosyltransferases 1 and 2 (POMT1 and POMT2), fukutin, and fukutin-related protein are responsible for this syndrome. In our previous study, we cloned Drosophila orthologs of human POMT1 and POMT2 and identified their activity. However, the mechanism of onset of this syndrome is not well understood. Furthermore, little is known about the behavioral properties of the Drosophila POMT1 and POMT2 mutants, which are called rotated abdomen (rt) and twisted (tw), respectively. First, we performed various kinds of behavioral tests and described in detail the muscle structures by using these mutants. The mutant flies exhibited abnormalities in heavy exercises such as climbing or flight but not in light movements such as locomotion. Defective motor function in mutants appeared immediately after eclosion and was exaggerated with aging. Along with motor function, muscle ultrastructure in the tw mutant was altered, as seen in human patients. We demonstrated that expression of RNA interference (RNAi) for the rt gene and the tw mutant was almost completely lethal and semi-lethal, respectively. Flies expressing RNAi had reduced lifespans. These findings clearly demonstrate that Drosophila POMT mutants are models for human muscular dystrophy. We then observed a high density of myoblasts with an enhanced degree of apoptosis in the tw mutant, which completely lost enzymatic activity. In this paper, we propose a novel mechanism for the development of muscular dystrophy: POMT mutation causes high myoblast density and position derangement, which result in apoptosis, muscle disorganization, and muscle cell defects.

Walker-Warburg Syndrome Manifesting as Leopard Spot Retinopathy, Retinal Detachment, and Microphthalmia

Walker-Warburg syndrome, also known as HARD+/-E, is a congenital autosomal recessive disorder characterized by hydrocephalus, agyria, and retinal dysplasia, with or without encephalocele. The authors describe an infant with Walker-Warburg syndrome who presented with microphthalmia, retinal detachment, and leopard spot retinopathy.

Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families

OBJECTIVE

Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of alpha-dystroglycan (alpha-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS.

METHOD

We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis.

RESULTS

We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults.

CONCLUSION

These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population.

A case of Walker-Warburg syndrome resulting from a homozygous POMT1 mutation

Walker--Warburg syndrome (WWS), the most severe alpha-dystroglycanopathy, is characterized by brain and eye anomalies, and congenital muscular dystrophy (CMD). So far at least four genes (POMT1, POMT2, Fukutin, and FKRP gene) have been implicated in WWS, accounting for about 30% of all cases. We report a male patient with WWS resulting from a homozygous nonsense mutation (R514X) in the POMT1 gene. The patient had congenital hydrocephalus which was detected at 29 weeks of gestation. A brain MRI obtained after birth revealed type II lissencephaly, hydrocephalus, and pontocerebellar hypoplasia. The case also exhibited severe ocular malformations and muscular hypotonia due to CMD.

Walker-Warburg syndrome

Walker-Warburg Syndrome (WWS) is a rare form of autosomal recessive congenital muscular dystrophy associated with brain and eye abnormalities. WWS has a worldwide distribution. The overall incidence is unknown but a survey in North-eastern Italy has reported an incidence rate of 1.2 per 100,000 live births. It is the most severe form of congenital muscular dystrophy with most children dying before the age of three years. WWS presents at birth with generalized hypotonia, muscle weakness, developmental delay with mental retardation and occasional seizures. It is associated with type II cobblestone lissencephaly, hydrocephalus, cerebellar malformations, eye abnormalities and congenital muscular dystrophy characterized by hypoglycosylation of α-dystroglycan. Several genes have been implicated in the etiology of WWS, and others are as yet unknown. Several mutations were found in the Protein O-Mannosyltransferase 1 and 2 (POMT1 and POMT2) genes, and one mutation was found in each of the fukutin and fukutin-related protein (FKRP) genes. Laboratory investigations usually show elevated creatine kinase, myopathic/dystrophic muscle pathology and altered α-dystroglycan. Antenatal diagnosis is possible in families with known mutations. Prenatal ultrasound may be helpful for diagnosis in families where the molecular defect is unknown. No specific treatment is available. Management is only supportive and preventive.

Glyc-O-genetics of Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is the most severe of a group of multiple congenital anomaly disorders known as the cobblestone lissencephalies. These are characterized by congenital muscular dystrophy in conjunction with severe brain malformation and ocular abnormalities. In the last 3 years, important progress has been made towards the elucidation of the genetic causes of these disorders. Mutations in three genes, POMT1, fukutin and FKRP, have been described for WWS, which together account for approximately 20% of patients with Walker-Warburg. It has become evident that some of the underlying genes may cause a broad spectrum of phenotypes, ranging from limb girdle muscular dystrophy type 2I to WWS. In some cases, a genotype-phenotype correlation can be recognized. In line with the known or proposed functions of the resolved genes, all patients with cobblestone lissencephaly show defects in the O-linked glycosylation of the glycoprotein alpha-dystroglycan. Perhaps, the missing genes underlying the remainder of the unexplained WWS patients have also to be sought in the pathways involved in O-linked protein glycosylation.

The role of defective glycosylation in congenital muscular dystrophy

The dystrophin glycoprotein complex (DGC) is an assembly of proteins spanning the sarcolemma of skeletal muscle cells. Defects in the DGC appear to play critical roles in several muscular dystrophies due to disruption of basement membrane organization. O -mannosyl oligosaccharides on alpha-dystroglycan, a major extracellular component of the DGC, are essential for normal binding of alpha-dystroglycan to ligands (such as laminin) in the extracellular matrix and subsequent signal transmission to actin in the cytoskeleton of the muscle cell. Muscle-Eye-Brain disease (MEB) and Walker-Warburg Syndrome (WWS) have mutations in genes encoding glycosyltransferases needed for O -mannosyl oligosaccharide synthesis. Myodystrophic myd mice and humans with Fukuyama Congenital Muscular Dystrophy (FCMD), congenital muscular dystrophy due to defective fukutin-related protein (FKRP) and MDC1D have mutations in putative glycosyltransferases. These human congenital muscular dystrophies and the myd mouse are associated with defective glycosylation of alpha-dystroglycan. It is expected other congenital muscular dystrophies will prove to have mutations in genes involved in glycosylation.

Mutations inPOMT1 are found in a minority of patients with Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder of infancy characterized by hydrocephalus, agyria, retinal dysplasia, congenital muscular dystrophy, and over migration of neurons through a disrupted pial surface resulting in leptomeningeal heterotopia. Although previous work identified mutations in the o-mannosyl transferase, POMT1, in 6 out of 30 WWS families [Beltran-Valero de Bernabe et al., 2002], the incidence of POMT1 mutations in WWS is not known. We sequenced the entire coding region of POMT1 in 30 consecutive, unselected patients with classic WWS. Two novel heterozygous mutations were found in two patients from non-consanguineous parents, whereas 28 other patients failed to show any POMT1 mutations. One patient was found to be heterozygous for a transition, g.1233T > A, which predicts p.Y352X. A second patient was found also to be heterozygous for a transition g.1790C > G, which predicts p.S537R. As an additional determination of the frequency of the POMT1 mutations in WWS, we tested for linkage of WWS to POMT1 in six consanguineous families. All six demonstrated heterozygosity and negative LOD scores at the POMT1 locus. From these data we show that POMT1 is an uncommon cause of WWS, the incidence of coding region mutations in this population of WWS being less than 7%. We conclude that while the incidence of POMT1 mutations in WWS can be as high as 20% as reported by Beltran-Valero de Bernabe et al. [2002] and it can be as low as approximately 7%, as reported here.

The congenital muscular dystrophies in 2004: a century of exciting progress

The congenital muscular dystrophies are a heterogeneous group of inherited disorders. The clinical features range from severe and often early fatal disorders to relatively mild conditions compatible with survival into adult life. The recent advances in the genetic basis of congenital muscular dystrophies have allowed to significantly improve our understanding of their pathogenesis and clinical diversity. These advances have also allowed to classify these forms according to a combination of clinical features and primary biochemical defects. In this review we present how the congenital muscular dystrophies field has evolved over the last decade from a clinical and genetic point of view.

Anaesthesia for a child with Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is a rare lethal autosomal recessive disorder manifested by characteristic central nervous system and eye malformations. We have not come across reports of general anaesthesia in a child with WWS in the English literature. We report a case of general anaesthesia in a 12-month-old male child with WWS. The child also had bilateral cleft lip, cleft palate, urogenital malformation and hydronephrosis. Despite many potential anaesthesia concerns, anaesthesia was uneventful in this child.

Clinical, genetic and histopathologic findings in two siblings with muscle-eye-brain disease

PURPOSE

We present the clinical, genetic and histopathologic findings in two siblings with Muscle-Eye-Brain Disease (MEB-D), an autosomal recessive disease characterized by mental retardation, muscular dystrophy, retinal hypoplasia and brain abnormalities.

METHODS

Clinical, histopathologic and gene mapping studies of a family with two normal and two children with MEB-D.

RESULTS

Two siblings presented in the first few months of life with developmental delay, hypotonia, and strabismus. MRI of the brain showed colpocephaly, pontine and cerebellar atrophy, and diffuse white matter disease. Both patients were blind and had high myopia, strabismus, and retinal and optic nerve abnormalities. The older boy had glaucoma. Both children died from uncontrolled seizures. There was retinal, choroidal and RPE atrophy and optic nerve hypoplasia on ocular histopathology. Both patients shared the same parental haplotypes at the MEB locus on chromosome 1p, while an unaffected sibling did not, indicating possible linkage to the MEB locus.

CONCLUSIONS

Patients with MEB-D have severe visual impairment from retinal and optic nerve hypoplasia. High myopia appears to be a consistent finding. The ocular manifestations of MEB-D appear to be distinct from those of patients with Walker-Warburg syndrome.

Renal-coloboma syndrome: report of a novel PAX2 gene mutation

PURPOSE

To report a novel sporadic PAX2 gene mutation in a child with atypical bilateral optic nerve coloboma and congenital renal hypoplasia.

DESIGN

Observational case report and experimental study.

METHODS

Mutational analysis of the PAX2 gene in a family.

RESULTS

A 9-year-old patient with a history of renal transplantation for congenital renal hypoplasia was found to have bilateral optic nerve coloboma during ophthalmic examination for cytomegalovirus retinitis. A previously unreported mutation in exon 2, delT 602 leading to a prematurely truncated protein was identified in the child but in neither of her parents, demonstrating a de novo mutation or germline mosaicism.

CONCLUSIONS

The causal relationship between PAX2 gene mutations and renal-coloboma syndrome is further supported by this novel mutation. Awareness of the systemic associations with optic nerve abnormalities and the ocular findings in syndromic renal diseases will facilitate the management of these highly variable disorders.

A child with muscle-eye-brain disease. Ophthalmological and neurological characteristics

PURPOSE

To describe a child with Muscle-Eye-Brain disease (MEB), one of three types of congenital muscular dystrophy associated with ocular abnormalities.

METHODS

Case report.

RESULTS

The child showed severe visual impairment due to progressive myopia and retinal degeneration, a pachygyria-type of migration disorder of the brain with a nodular cortical surface, i.e. cobblestone cortex, as well as muscular weakness and severe mental retardation.

CONCLUSION

Ophthalmological assessments are important to help to diagnose and follow children with congenital muscular dystrophy.

Walker-Warburg syndrome. Report of two cases

The purpose of this study is to describe two infants that were diagnosed with Walker-Warburg syndrome (WWS), a rare form of congenital muscular dystrophy (CMD). They were studied in their clinical, laboratory, and neuroradiologic features. The index case had a brain magnetic resonance imaging (MRI) and the second patient had a head computerized tomography (CT). In addition, a literature review was performed to describe the main forms of CMD. The index case fulfilled all criteria for WWS. A brain MRI performed at age 4 months served to corroborate the clinical diagnosis, showing severe hydrocephalus, type II lissencephaly, cerebellar vermian aplasia, and a hypoplastic brain stem. The authors were able to establish a retrospective diagnosis of WWS in the index case's older sister, based upon her clinical picture and head CT report.

Autosomal dominant cataracts and Peters anomaly in a large Australian family

Peters anomaly is a congenital corneal opacity with underlying defects in the posterior stroma, Descemets membrane and corneal endothelium. It is a disorder resulting from abnormal migration or function of neural crest cells and may include abnormalities of other anterior segment structures, such as the lens and iris. We report a family in which anterior segment abnormalities, including Peters anomaly and cataracts, were inherited in an autosomal dominant fashion. Although the PAX6 gene on chromosome 11 has been shown to be involved in some cases of anterior segment developmental defects, we found no evidence that the condition in this family is linked to the PAX6 gene. Identification of this gene will indicate another gene with major involvement in the development of the anterior segment of the eye.

Congenital muscular dystrophies: 1997 update

The congenital muscular dystrophies (CMDs) comprise a heterogeneous group of muscle disorders with onset in utero or during the first year of life. Several forms of CMD show various types of brain involvement in addition to a muscular dystrophy. Two forms are defined at the molecular level: merosin deficient-CMD caused by mutations in the LAMA2-gene on chromosome 6q2. Fukuyama congenital muscular dystrophy (FCMD) is prevalent in Japan and caused by an as yet unidentified gene on chromosome 9q31. At least two further forms of CMD with brain involvement are nosologically well defined: Walker--Warburg-CMD is characterized by lissencephaly type 11, eye dysgenesis and muscular dystrophy. This autosomal recessive disorder is fatal or results in complete lack of development. A similar but much milder phenotype with pachygyria of the brain, various degrees of eye changes and milder muscular dystrophy that is compatible with achievement of simple motor milestones has been described under the name of muscle-eye-brain disease (MEB) in Finland. A number of nosologically less distinct forms of muscular dystrophy have been outlined such as 'pure' CMD without brain involvement, CMD with cerebellar hypoplasia or CMD type Ullrich with hyperelasticity of the distal joints. Several other CMD phenotypes are known, some of which are suggestive of more distinctly separate nosological entities due to their occurrence in siblings or due to a characteristic pattern of clinical, histopathological and imaging features, and await further clarification.

A novel pattern of oculocerebral malformation

AIMS/BACKGROUND

To report a novel pattern of oculocerebral malformation related to the group of diseases characterised by cobblestone lissencephaly.

METHODS

By means of a case report with specialist descriptions of the novel neuropathological and ophthalmic pathology features.

RESULTS

The patient, born to healthy consanguineous parents, presented in the neonatal period with jaundice, convulsions, and macrocephaly. Computed tomography demonstrated hydrocephalus and abnormal cerebral gyration. Ophthalmic examination revealed severe myopia and segments of retinal atrophy. Cytogenetic investigation revealed a balanced reciprocal translocation (46,XX,t(5p11;19q13.1)) that was inherited from the mother and was present in several normal relatives. Mild short stature and profound mental handicap were evident. The child died aged 7 years. At necropsy the brain showed 'cobblestone' (type II) lissencephaly. Cerebellar cortical architecture was abnormal and the brain stem lacked cerebral peduncles, basis pontis, and pyramids. Biopsies of skeletal muscles were normal. The ocular abnormalities included discrete sectors of retina of varying thickness with disordered neuronal lamination and gliosis. The optic nerve was gliotic and contained few nerve fibres. The anterior iris surface was studded with cellular stromal nodules which appear to be melanocytic in nature.

CONCLUSION

Retinal dysgenesis occurs in the group of syndromes with 'cobblestone lissencephaly', the best known being Walker-Warburg syndrome. In this case, relatively long survival, lack of muscular dystrophy, and novel ocular pathology distinguish it from the other diagnoses in this group of syndromes. We suggest this child was affected by a distinct and novel oculocerebral syndrome.

Congenital muscular dystrophy: a review of the literature

Congenital muscular dystrophy (CMD) is a condition in which there are already at birth, marked hypotonia, generalized muscle weakness and frequently multiple contractures. CMD has recently been classified into four categories: CMD I, the classical or "pure' CMD without severe impairment of intellectual development; CMD II, the Fukuyama type CMD with muscle and structural brain abnormalities; CMD III and IV with muscle, eye and brain abnormalities; the milder Finnish type CMD (CMD III) and the severe Walker-Warburg syndrome (CMD IV). Data of the literature concerning those different CMD types have been reviewed and are presented with emphasis on signs and symptoms, clinical course, laboratory, neurophysiological, radiological, morphological and genetic characteristics.

Hydrocephalus, skeletal anomalies, and mental disturbances in a mother and three daughters: a new syndrome

We report on a family in which a mother and her 3 daughters have delayed psychomotor development and/or psychosis, hydrocephalus with white matter alterations, arachnoid cysts, skeletal anomalies consisting of brachydactyly, and Sprengel anomaly. Biochemical and cytogenetic analyses were normal on all 4 patients. The pattern of inheritance, clinical manifestations, and variability of expression suggest that this is a new hydrocephalus syndrome possibly transmitted as an X-linked dominant trait.

The childhood muscular dystrophies: diseases sharing a common pathogenesis of membrane instability

New observations demonstrate that several childhood forms of muscular dystrophy share a common pathogenesis. In muscle, dystrophin occurs as part of a membrane complex (dystrophin-glycoprotein) linking the cytoskeleton to the basal lamina. In Duchenne muscular dystrophy, dystrophin deficiency disrupts the linkage of the integral glycoproteins of the sarcolemma and leads to muscle fiber necrosis. In severe childhood autosomal recessive muscular dystrophy, a selective deficiency of adhalin (50-kd glycoprotein) also causes dysfunction of the dystrophin-glycoprotein complex. Most recently, a form of congenital muscular dystrophy demonstrates deficiency of laminin M (merosin) further demonstrating that sarcolemmal instability results from defects in structural proteins of the basal lamina. Animal models have been identified also demonstrating defects in specific proteins linking the subsarcolemmal cytoskeleton to the extracellular matrix. The mdx mouse has a defect in the gene encoding dystrophin. The cardiomyopathic hamster shows a specific deficiency of adhalin in skeletal muscle. The dy/dy mouse has been found deficient in merosin. These animal models will help researchers to understand their human counterparts and provide a system for testing therapeutic strategies.

Neurosurgical management of Walker-Warburg syndrome

The Walker-Warburg syndrome (WWS) is a lethal complex of the central nervous system and the eyes. At present its cause is unknown, but clinical evidence strongly suggests that it is an autosomal-recessively inherited disorder. We report a series of nine children with WWS. The diagnosis was established by the detection of lissencephaly, hydrocephalus, and cerebellar malformation on computed tomography. All children exhibited profound psychomotor retardation and ocular abnormalities (in their anterior or posterior eye chambers). The existence of an occipital encephalocele in eight cases was the main diagnostic clue to WWS. Six patients were investigated for the presence for congenital muscular dystrophy, which was confirmed in only four of them. There were no patients with a cleft lip or palate. We studied the incidence of WWS in Spain and estimated it at 0.21 cases per 10,000 live-born children. In our series, WWS was prevalent in the Spanish gypsy population. Consanguinity was present in five of seven affected families. In a case of pregnancy with twins, one of the siblings was unaffected. Eight patients were treated with ventriculoperitoneal shunts and seven underwent encephalocele repair. Histological study of the excised encephaloceles demonstrated two different patterns. Interestingly, one of the infants showed coronal craniosynostosis. Finally, we include in the appendix, for completeness, a report of the case of the sibling of a WWS patient with acrania-exencephaly.

Abnormal electroretinogram associated with developmental brain anomalies

PURPOSE

We have encountered abnormal ERGs associated with optic nerve hypoplasia, macular, optic nerve and chorioretinal colobomata and developmental brain anomalies. Brain anomalies include cortical dysgenesis, lissencephaly, porencephaly, cerebellar and corpus callosum hypoplasia. We describe six exemplar cases.

METHODS

Scotopic and photopic ERGs adherent to international standards were performed as well as photopic ERGs to long-duration stimuli. CT or MRI studies were also done. The ERGs were compared to age-matched normal control subjects.

RESULTS

ERG changes include reduced amplitude b-waves to blue and red stimuli under scotopic testing conditions. Implicit times were often delayed. The photopic responses also showed reduced amplitude a- and b-waves with implicit time delays. The long-duration photopic ERG done in one case shows attenuation of both ON- and OFF-responses.

CONCLUSIONS

Common underlying developmental genetic or environmental unifying casualties are speculated to be at fault in causing these cases of associated retinal and brain abnormalities. No single etiology is expected. Multiple potential causes acting early in embryogenesis effecting neuronal induction, migration and differentiation are theorized. These occur at a time when brain and retinal cells are sufficiently undifferentiated to be similarly effected. We call these cases examples of Brain Retina Neuroembryodysgenesis (BRNED). Homeobox and PAX genes with global neuronal developmental influences are gene candidates to unify the observed disruption of brain and retinal cell development. The ERG can provide a valuable clinical addition in understanding and ultimately classifying these disorders.

Lissencephaly syndromes: clinical aspects

We report clinical and neurophysiological findings in six children (three female, three male) with type I lissencephaly and three children (all female) with type II lissencephaly (Walker-Warburg syndrome). In type I lissencephaly the diagnosis is based only on electroencephalographic (EEG) signs, whereas in type II lissencephaly the diagnosis rests on clinical signs. In type I lissencephaly the EEG typically shows high alpha-beta activity, which is not seen in type II lissencephaly.

Congenital muscular dystrophy. A study on the variability of morphological changes and dystrophin distribution in muscle biopsies

Histomorphological and histochemical variability was studied in muscle specimens from 30 patients with congenital muscular dystrophy (CMD). We found involvement of the central nervous system in 8 patients (Fukuyama CMD, F-CMD), involvement of the brain and the eyes in 5 patients (muscle, eye and brain disease, MEB-D) and hypodense white matter on the CT scans of 2 patients with (sub)normal intelligence (occidental-type cerebromuscular dystrophy, O-CMD). No morphological hallmarks were found to differentiate these subgroups. Only fat cell infiltration was found to be increased with increasing age in 'pure' CMD (pure-CMD). The morphological data did not appear to be correlated with the clinical severity or type of dystrophy (pure-CMD, F-CMD, MEB-D and O-CMD). Immunohistochemistry with dystrophin, vimentin and desmin antibodies in 14 patients (6 pure-CMD, 5 F-CMD, 2 MEB-D and 1 O-CMD) showed a normal expression pattern.

Inflammatory Myopathy and Walker-Warburg Syndrome: Etiologic Implications

Walker-Warburg syndrome is a well delineated clinical entity with characteristic brain and eye anomalies. Recent diagnostic surveys have revealed that muscular dystrophy is an obligatory feature of this syndome. We report a patient with an inflammatory myopathy that preceded dystrophic changes. While reports of parental consanguinity and multiple affected sibships strongly suggest an autosomal recessive genetic basis for this syndrome, previous pathological analyses of the CNS have suggested an inflammatory process. Our case supports both the notion of an aberrant inflammatory process that is likely under genetic control or etiologic heterogeneity (phenocopies) underlying this syndrome.

Ocular findings in cerebro-ocular-myopathy syndrome (COMS). A possible role of growth factors?

The clinical and histopathological findings are described in a case of cerebral and ocular abnormalities associated with (congenital) muscular dystrophy. Histopathological examination of the eyes revealed a fetal configuration of the anterior chamber angle, elongated ciliary processes, cataract, persistence of primary hyperplastic vitreous and total retinal detachment with retinal dysplasia. The similarity of ocular findings in Walker-Warburg syndrome, muscle-eye-brain disease and Fukuyama's congenital muscular dystrophy, and the role of growth factors as a possible unifying (foetal) cause are discussed. This case has been presented at the meeting of the EOPS Verhoeff Society, Nürnberg 1991.

Fukuyama-type congenital muscular dystrophy and the Walker-Warburg syndrome

We compared the neuropathological findings in two cases of the Walker-Warburg syndrome (WWS) with those in 6 of Fukuyama-type congenital muscular dystrophy (FCMD). Remarkable differences were noticed between the two conditions. The central nervous system (CNS) dysplasia in WWS, which involved diffuse agyria and hydrocephalus, was more severe than that in FCMD. In WWS the septum pellucidum was absent, and the corpus callosum, basal ganglia and thalami were markedly hypoplastic. The cerebellum was severely hypoplastic and the vermis was partly absent. The pyramidal tracts could not be identified. On the other hand, the general configuration of the CNS was well preserved in FCMD. The cerebral cortices exhibited diffuse or focal micropolygyria with or without a few pachygyric lesions, but the severity was variable. The cerebellum was not hypoplastic, but exhibited focal micropolygyria. The pyramidal tracts were aberrant. WWS and FCMD, however, did not show any distinct differences on microscopic analysis of the cerebral cortices. There was leptomeningeal glio-mesenchymal overgrowth, and the horizontal lamination of the nerve cells was distorted throughout by proliferating gliovascular bundles or septa. We found in this study that the CNS pathology in WWS was compatible with type II lissencephaly, and thus differed from that in FCMD. Hypoplasia of the cerebellum and a partial absence of the vermis also seemed to be predominant features of WWS, which can be used to differentiate WWS from FCMD. In this study, we concluded that FCMD and WWS are different disease entities because they differ in their clinical manifestations, including eye lesions and CNS pathology, and because no familial concomitance of FCMD and WWS has been reported.

Congenital muscular dystrophy, brain and eye abnormalities: one or more clinical entities?

Four children with congenital muscular dystrophy (CMD), eye and brain abnormalities are described. Their clinical and neuroradiological features are compatible with a diagnosis of Walker-Warburg syndrome (WWS), according to the criteria proposed by Dobyns et al. (i.e., presence of type II lissencephaly, typical cerebellar and retinal malformations, CMD), who also conclude that WWS is indistinguishable from the muscle-eye-brain disease (MEBD) described by Santavuori. On the basis of our own experience and two recently published series, we emphasize certain features that are different in patients with WWS and patients with MEBD, which make their inclusion in the same syndrome dubious.

Unilateral benign medulloepithelioma associated with bilateral retinal detachment

A two-month-old girl presented with a unilateral benign cystic medulloepithelioma from the ciliary body associated with bilateral retinal non-attachment. The authors discuss the histopathologic findings and the pathogenesis of the congenital retinal non-attachment: are these incidental occurrences or do they arise from a common pathogenetic mechanism?

Neuropathological findings in muscle-eye-brain disease (MEB-D). Neuropathological delineation of MEB-D from congenital muscular dystrophy of the Fukuyama type

Congenital muscular dystrophy (CMD) associated with cerebro-ocular dysplasia named muscle-eye-brain disease (MEB-D) is described in two sisters. Progressive hypotonia, mental retardation and severe visual failure appeared immediately after birth. Pathological examination demonstrated muscular dystrophy, hydrocephalus, type II lissencephaly and defective eye development of foetal origin. The great similarity of the clinical and neuropathological picture of both sisters is in agreement with an autosomal recessive inheritance. Neuropathological distinction between Fukuyama-CMD and MEB-D is a more severe and earlier cerebral developmental defect and the association with ocular dysplasia in MEB-D.

Walker-Warburg syndrome with microtia and absent auditory canals

Walker-Warburg syndrome is a lethal, autosomal recessive disorder characterized by anomalies of the central nervous system and eye. Typical findings include hydrocephalus, agyria, retinal dysplasia, cerebellar dysgenesis, anterior chamber dysgenesis, and encephalocele. Recently, the phenotypic spectrum has been expanded to include congenital muscular dystrophy. Two sibs with Walker-Warburg syndrome are reported. One sib had congenital glaucoma and hydrocephalus. The other sib had hydrocephalus, microtia, absent auditory canals, and pale retinas, barely within the phenotypic spectrum of the disorder. Elevation of muscle enzymes was consistent with the diagnosis of Walker-Warburg syndrome.

Fukuyama congenital muscular dystrophy in two Australian female siblings

The clinical course of two female siblings with congenital muscular dystrophy is briefly described, and includes congenital cerebral malformations consisting of pachygyria, polymicrogyria and white matter abnormalities. The first sibling died in infancy; the second is now 18 years of age. The changes found at autopsy in the first sibling are identical to MRI changes in the surviving sibling.

Walker-Warburg syndrome. Case report and literature review

The Walker-Warburg syndrome (WWS) is a fatal dysmorphic disorder of unknown etiology, but strongly suggests an autosomal recessive mode of inheritance. It is characterized by severe congenital oculo-cerebral malformations (lissencephaly, congenital hydrocephalus, and ocular lesions). The authors report a case of WWS that occurred in a consanguineous union, with a review of the literature. Possible pathogenesis, and disorders sharing the features of WWS are discussed. Families-at-risk for WWS should be identified for prenatal diagnosis and for genetic counselling.

Ocular manifestations in Fukuyama type congenital muscular dystrophy

We describe a child with Fukuyama type congenital muscular dystrophy (FCMD) who had several ocular manifestations since birth. These included high myopia, strabismus, nystagmus and optic atrophy of both eyes. Later he developed retinal detachment of both eyes. Our survey of 33 cases with FCMD revealed that high myopia and optic atrophy are common in FCMD. Retinal detachment was reported in two cases in addition to the present one and was considered to be of developmental origin. The association of congenital muscular dystrophy with brain changes and ocular anomalies were found in FCMD, muscle, eye and brain disease (MEB) and Walker-Warburg syndrome (WWS). Ocular manifestations in FCMD were, in general, less severe than those in WWS or MEB. Our study suggests that FCMD, MEB and WWS are developmental abnormalities with a continual spectrum of disease severity.

Congenital muscular dystrophy

We report the cases of 18 patients with congenital muscular dystrophy, six of whom also have involvement of the central nervous system, corresponding to the Fukuyama type of congenital muscular dystrophy. In four patients, both the central nervous system and the eyes are involved, and the diagnosis of "muscle, eye and brain disease" was made. A comparative study of these patients with those whose cases were recently reported indicates that there is a wide variability of clinical and laboratory expression of the dystrophy, but a constant feature in all patients is a progression of motor disability. The association of congenital muscular dystrophy with brain abnormalities indicates a poor clinical prognosis. At present it remains an open question whether the three variants of the disease are separate diseases or only different expressions of the same syndrome, but our study tends to support the latter hypothesis.

Walker-Warburg syndrome in a Japanese patient

We report the first Japanese female patient with Walker-Warburg syndrome. She had generalized muscle hypotonia with hydrocephalus due to Dandy-Walker malformation and bilateral microphthalmia with opaque corneas. She had severe motor and mental retardation. Muscle histology reflected advanced changes of muscular dystrophy. We discuss the relationship between Fukuyama congenital muscular dystrophy and Walker-Warburg syndrome, both of which fall within a spectrum of developmental abnormalities with a common cause. In Fukuyama congenital muscular dystrophy, ocular abnormalities are less severe.

Ocular malformations and lissencephaly

Retinal dysplasia and agyria without cortical lamination are the constant findings in this autosomal recessive syndrome. There may also be anterior chamber malformations, cataract, and microphthalmos. Brain autopsies have shown a variety of associated malformations such as posterior encephalocele, Arnold-Chiari malformation, agenesis of the septum pellucidum and of the corpus callosum, agenesis of the vermis and hypoplasia of the cerebellum. Muscular dystrophy is probably present in most of these patients. Within the last few years, over 20 cases with a complete autopsy have been described. The syndrome should be differentiated from other syndromes with retinal non-attachment and retinal dysplasia, and from syndromes with hydrocephalus or encephalocele without these ocular features.