Fetal Presentation of Walker-Warburg Syndrome with Compound Heterozygous POMT2 Missense Mutations.

Background: Walker-Warburg syndrome (WWS) (OMIM #236670) is an autosomal recessive disorder characterized by congenital muscular dystrophy, hydrocephalus, cobblestone lissencephaly, and retinal dysplasia. The main genes involved are: POMT1, POMT2, POMGNT1, FKTN, LARGE1, and FKRP. Case report: We present a fetus with WWS showing at ultrasound severe triventricular hydrocephalus. Pregnancy was legally terminated at 21 weeks +2 days of gestation. In vivo and postmortem magnetic resonance revealed corpus callosum agenesis and cerebellar hypoplasia. Cobblestone lissencephaly was observed at post-mortem. Next generation sequencing (NGS) of 193 genes, performed on fetal DNA extracted from amniocytes, detected two heterozygous mutations in the POMT2 gene. The c.1238G > C p.(Arg413Pro) mutation was paternally inherited and is known to be pathogenic. The c.553G > A p.(Gly185Arg) mutation was maternally inherited and has not been previously described. Conclusion: Compound heterozygous mutations in the POMT2 gene caused a severe cerebral fetal phenotype diagnosed prenatally at midgestation allowing therapeutic pregnancy termination.

TGFBI Expressed by Bone Marrow Niche Cells and Hematopoietic Stem and Progenitor Cells Regulates Hematopoiesis.

The interactions of hematopoietic stem and progenitor cells (HSPCs) with extracellular matrix (ECM) components and cells from the bone marrow (BM) microenvironment control their homeostasis. Regenerative BM conditions can induce expression of the ECM protein transforming growth factor beta-induced gene H3 (TGFBI or BIGH3) in murine HSPCs. In this study, we examined how increased or reduced TGFBI expression in human HSPCs and BM mesenchymal stromal cells (MSCs) affects HSPC maintenance, differentiation, and migration. HSPCs that overexpressed TGFBI showed accelerated megakaryopoiesis, whereas granulocyte differentiation and proliferation of granulocyte, erythrocyte, and monocyte cultures were reduced. In addition, both upregulation and downregulation of TGFBI expression impaired HSPC colony-forming capacity of HSPCs. Interestingly, the colony-forming capacity of HSPCs with reduced TGFBI levels was increased after long-term co-culture with MSCs, as measured by long-term culture-colony forming cell (LTC-CFC) formation. Moreover, TGFBI downregulation in HSPCs resulted in increased cobblestone area-forming cell (CAFC) frequency, a measure for hematopoietic stem cell (HSC) capacity. Concordantly, TGFBI upregulation in HSPCs resulted in a decrease of CAFC and LTC-CFC frequency. These results indicate that reduced TGFBI levels in HSPCs enhanced HSC maintenance, but only in the presence of MSCs. In addition, reduced levels of TGFBI in MSCs affected MSC/HSPC interaction, as observed by an increased migration of HSPCs under the stromal layer. In conclusion, tight regulation of TGFBI expression in the BM niche is essential for balanced HSPC proliferation and differentiation.

Biallelic Mutations in TMTC3, Encoding a Transmembrane and TPR-Containing Protein, Lead to Cobblestone Lissencephaly.

Cobblestone lissencephaly (COB) is a severe brain malformation in which overmigration of neurons and glial cells into the arachnoid space results in the formation of cortical dysplasia. COB occurs in a wide range of genetic disorders known as dystroglycanopathies, which are congenital muscular dystrophies associated with brain and eye anomalies and range from Walker-Warburg syndrome to Fukuyama congenital muscular dystrophy. Each of these conditions has been associated with alpha-dystroglycan defects or with mutations in genes encoding basement membrane components, which are known to interact with alpha-dystroglycan. Our screening of a cohort of 25 families with recessive forms of COB identified six families affected by biallelic mutations in TMTC3 (encoding transmembrane and tetratricopeptide repeat containing 3), a gene without obvious functional connections to alpha-dystroglycan. Most affected individuals showed brainstem and cerebellum hypoplasia, as well as ventriculomegaly. However, the minority of the affected individuals had eye defects or elevated muscle creatine phosphokinase, separating the TMTC3 COB phenotype from typical congenital muscular dystrophies. Our data suggest that loss of TMTC3 causes COB with minimal eye or muscle involvement.

Prenatal Diagnosis of Lissencephaly Type 2 using Three-dimensional Ultrasound and Fetal MRI: Case Report and Review of the Literature.

Lissencephaly is a genetic heterogeneous autosomal recessive disorder characterized by the classical triad: brain malformations, eye anomalies, and congenital muscular dystrophy. Prenatal diagnosis is feasible by demonstrating abnormal development of sulci and gyri. Magnetic resonance imaging (MRI) may enhance detection of developmental cortical disorders as well as ocular anomalies. We describe a case of early diagnosis of lissencephaly type 2 detected at the time of routine second trimester scan by three-dimensional ultrasound and fetal MRI. Gross pathology confirmed the accuracy of the prenatal diagnosis while histology showed the typical feature of cobblestone cortex. As the disease is associated with poor perinatal prognosis, early and accurate prenatal diagnosis is important for genetic counseling and antenatal care.

Prenatal Diagnosis of Lissencephaly Type 2 using Three-dimensional Ultrasound and Fetal MRI: Case Report and Review of the Literature / Diagnóstico pré-natal de lissencefalia tipo 2 por meio da ultrassonografia e ressonância magnética fetal: relato de caso e revisão da literatura

Abstract Lissencephaly is a genetic heterogeneous autosomal recessive disorder characterized by the classical triad: brain malformations, eye anomalies, and congenital muscular dystrophy. Prenatal diagnosis is feasible by demonstrating abnormal development of sulci and gyri. Magnetic resonance imaging (MRI) may enhance detection of developmental cortical disorders as well as ocular anomalies. We describe a case of early diagnosis of lissencephaly type 2 detected at the time of routine second trimester scan by three-dimensional ultrasound and fetal MRI. Gross pathology confirmed the accuracy of the prenatal diagnosis while histology showed the typical feature of cobblestone cortex. As the disease is associated with poor perinatal prognosis, early and accurate prenatal diagnosis is important for genetic counseling and antenatal care.

Resumo Lissencefalia são doenças genéticas autossômicas recessivas heterogêneas caracterizadas pela tríade clássica: malformações do cérebro, anomalias oculares e distrofia muscular congênita. Diagnóstico pré-natal é factível pela demonstração do desenvolvimento anormal de sulcos e giros. Ressonância magnética ( RM ) melhora a detecção de distúrbios do desenvolvimento cortical, bem como as anomalias oculares. Descrevemos um caso de diagnóstico precoce de lisencefalia tipo 2 detectado no momento do ultrassom morfológico de segundo trimestre pela ultrassonografia tridimensional e RM fetal. A macroscopia confirmou a acurácia do diagnóstico pré-natal, enquanto que a microscopia mostrou a típica característica de córtex em cobblestone. Como a doença está associada à um pobre prognóstico perinatal, o precoce e acurado diagnóstico pré-natal é importante para o aconselhamento genético e seguimento da gestação.

Prenatal diagnosis of cobblestone lissencephaly associated with Walker-Warburg syndrome based on a specific sonographic pattern.

We report a specific sonographic cerebral pattern of cobblestone lissencephaly (CL) that has not been described previously. This pattern was encountered in four index cases and allowed prenatal diagnosis of CL associated with Walker-Warburg syndrome. The pattern included both an outer echogenic band with reduced pericerebral space, corresponding to an infra- and supratentorial extracortical layer of neuroglial overmigration on pathological examination, and a 'Z'-shaped appearance of the brainstem. This pattern was found as early as 14 weeks' gestation in one of our cases.

A case of plummer-vinson syndrome associated with Crohn's disease.

Plummer-Vinson syndrome manifests as cervical dysphagia, iron deficiency anemia, an upper esophageal web, and atrophic glossitis. The cause of the esophageal web is thought to be iron deficiency anemia; however, the cause of Plummer-Vinson syndrome has not been established. Crohn's disease is usually accompanied by malnutrition and iron deficiency anemia; however, no case of concomitant Crohn's disease and Plummer-Vinson syndrome with aggravated malnutrition and anemia has been previously reported. Here, we report on a rare case of Plummer-Vinson syndrome in a Crohn's disease patient, which caused malnutrition and constipation.

A Case of Plummer-Vinson Syndrome Associated with Crohn's Disease / 대한소화기학회지

Plummer-Vinson syndrome manifests as cervical dysphagia, iron deficiency anemia, an upper esophageal web, and atrophic glossitis. The cause of the esophageal web is thought to be iron deficiency anemia; however, the cause of Plummer-Vinson syndrome has not been established. Crohn's disease is usually accompanied by malnutrition and iron deficiency anemia; however, no case of concomitant Crohn's disease and Plummer-Vinson syndrome with aggravated malnutrition and anemia has been previously reported. Here, we report on a rare case of Plummer-Vinson syndrome in a Crohn's disease patient, which caused malnutrition and constipation.

Novel mutations in the fukutin gene in a boy with asymptomatic hyperCKemia.

Mutations in the fukutin gene were first identified in Japanese patients with classic Fukuyama congenital muscular dystrophy, a severe form of congenital muscular dystrophy associated with cobblestone lissencephaly and ocular defects. Patients of different ethnicities and with milder phenotypes, including limb girdle muscular dystrophy and cardiomyopathy without brain impairment, have also been reported. The hallmark of this disorder, regardless of the clinical outcome, is moderate-to-severe hypoglycosylation of alpha-dystroglycan in muscle sections. We describe the case of a boy harboring two novel mutations in fukutin gene and presenting a five-year history of asymptomatic hyperCKemia, without overt muscle, brain or ocular involvement. Genetic investigations, guided by the presence of moderate myopathic changes on muscle biopsy with loss of immunodetectable alpha-dystroglycan, led to a definitive diagnosis. Cardiac and echocardiographic examinations at follow-up disclosed low normal left ventricular function but no active cardiovascular symptoms. We suggest that fukutin mutations should be sought in asymptomatic hyperCKemia and subclinical heart dysfunction.

Conventional magnetic resonance imaging and diffusion tensor imaging studies in children with novel GPR56 mutations: further delineation of a cobblestone-like phenotype.

GPR56-related bilateral frontoparietal polymicrogyria (BFPP) is a rare recessively inherited disorder of neuronal migration caused by mutations of GPR56. To better delineate the clinical, molecular, and neuroradiological phenotypes associated with BFPP, we performed conventional magnetic resonance imaging and diffusion tensor imaging studies in a series of prospectively enrolled patients carrying novel GPR56 mutations. All subjects with GPR56-related BFPP showed a characteristic morphological pattern, including abnormalities of the cerebellar cortex with cerebellar cysts located at the periphery, a mildly thick corpus callosum, and a flat pons. Significant alterations of myelination and white matter tract abnormalities were documented. The present study confirms the phenotypic overlap between GPR56-related brain dysgenesis and other cobblestone-like syndromes and illustrates the contribution of 3D neuroimaging in the characterization of malformations of cortical development.

Cobblestone lissencephaly in Schinzel-Giedion syndrome.

The brain of a 5-year-old boy with Schinzel-Giedion syndrome displayed a cobblestone appearance of orbital and lateral aspects of frontal lobes due to widespread glioneuronal meningeal heterotopia. Meningeal heterotopia consisted of scattered neurons, neurofilament positive axons, and myelinated fibers accompanied by striking astrocytic gliosis. The underlying cortex showed gaps in the pial basal lamina, distorted neuronal layering, and focal polymicrogyria. The number of capillaries appeared increased throughout the brain. Mild hydrocephalus was associated with a slight atrophy of corpus callosum as well as villous hyperplasia and marked stromal degeneration of the choroid plexus. Our findings suggest that Schinzel-Giedion syndrome may represent One more entity within enlarging spectrum of lissencephalic cortical dysplasia syndromes.

Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly.

Cobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the arachnoid space forms an extracortical layer that produces agyria and/or a "cobblestone" brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits. These include Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN, and FKRP identified these diseases as alpha-dystroglycanopathies. Our exhaustive screening of these six genes, in a cohort of 90 fetal cases, led to the identification of a mutation in only 53% of the families, suggesting that other genes might also be involved. We therefore decided to perform a genome-wide study in two multiplex families. This allowed us to identify two additional genes: TMEM5 and ISPD. Because TMEM has a glycosyltransferase domain and ISPD has an isoprenoid synthase domain characteristic of nucleotide diP-sugar transferases, these two proteins are thought to be involved in the glycosylation of dystroglycan. Further screening of 40 families with cobblestone lissencephaly identified nonsense and frameshift mutations in another four unrelated cases for each gene, increasing the mutational rate to 64% in our cohort. All these cases displayed a severe phenotype of cobblestone lissencephaly A. TMEM5 mutations were frequently associated with gonadal dysgenesis and neural tube defects, and ISPD mutations were frequently associated with brain vascular anomalies.

Cobblestone lissencephaly: neuropathological subtypes and correlations with genes of dystroglycanopathies.

Cobblestone lissencephaly represents a peculiar brain malformation with characteristic radiological anomalies, defined as cortical dysplasia combined with dysmyelination, dysplastic cerebellum with cysts and brainstem hypoplasia. Cortical dysplasia results from neuroglial overmigration into the arachnoid space, forming an extracortical layer, responsible for agyria and/or 'cobblestone' brain surface and ventricular enlargement. The underlying mechanism is a disruption of the glia limitans, the outermost layer of the brain. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal recessive diseases with cerebral, ocular and muscular deficits, Walker-Warburg syndrome, muscle-eye-brain and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN and FKRP genes attributed these diseases to α-dystroglycanopathies. However, studies have not been able to identify causal mutations in the majority of patients and to establish a clear phenotype/genotype correlation. Therefore, we decided to perform a detailed neuropathological survey and molecular screenings in 65 foetal cases selected on the basis of histopathological criteria. After sequencing the six genes of α-dystroglycanopathies, a causal mutation was observed in 66% of cases. On the basis of a ratio of severity, three subtypes clearly emerged. The most severe, which we called cobblestone lissencephaly A, was linked to mutations in POMT1 (34%), POMT2 (8%) and FKRP (1.5%). The least severe, cobblestone lissencephaly C, was linked to POMGNT1 mutations (18%). An intermediary type, cobblestone lissencephaly B, was linked to LARGE mutations (4.5%) identified for the first time in foetuses. We conclude that cobblestone lissencephaly encompasses three distinct subtypes of cortical malformations with different degrees of neuroglial ectopia into the arachnoid space and cortical plate disorganization regardless of gestational age. In the cerebellum, histopathological changes support the novel hypothesis that abnormal lamination arises from a deficiency in granule cells. Our studies demonstrate the positive impact of histoneuropathology on the identification of α-dystroglycanopathies found in 66% of cases, while with neuroimaging criteria and biological values, mutations are found in 32-50% of patients. Interestingly, our morphological classification was central in the orientation of genetic screening of POMT1, POMT2, POMGNT1, LARGE and FKRP. Despite intensive research, one-third of our cases remained unexplained; suggesting that other genes and/or pathways may be involved. This material offers a rich resource for studies on the affected neurodevelopmental processes of cobblestone lissencephaly and on the identification of other responsible gene(s)/pathway(s).

G protein-coupled receptor 56 and collagen III, a receptor-ligand pair, regulates cortical development and lamination.

GPR56, an orphan G protein-coupled receptor (GPCR) from the family of adhesion GPCRs, plays an indispensable role in cortical development and lamination. Mutations in the GPR56 gene cause a malformed cerebral cortex in both humans and mice that resembles cobblestone lissencephaly, which is characterized by overmigration of neurons beyond the pial basement membrane. However, the molecular mechanisms through which GPR56 regulates cortical development remain elusive due to the unknown status of its ligand. Here we identify collagen, type III, alpha-1 (gene symbol Col3a1) as the ligand of GPR56 through an in vitro biotinylation/proteomics approach. Further studies demonstrated that Col3a1 null mutant mice exhibit overmigration of neurons beyond the pial basement membrane and a cobblestone-like cortical malformation similar to the phenotype seen in Gpr56 null mutant mice. Functional studies suggest that the interaction of collagen III with its receptor GPR56 inhibits neural migration in vitro. As for intracellular signaling, GPR56 couples to the Gα(12/13) family of G proteins and activates RhoA pathway upon ligand binding. Thus, collagen III regulates the proper lamination of the cerebral cortex by acting as the major ligand of GPR56 in the developing brain.

GPR56-related bilateral frontoparietal polymicrogyria: further evidence for an overlap with the cobblestone complex.

GPR56 mutations cause an autosomal recessive polymicrogyria syndrome that has distinctive radiological features combining bilateral frontoparietal polymicrogyria, white matter abnormalities and cerebellar hypoplasia. Recent investigations of a GPR56 knockout mouse model suggest that bilateral bifrontoparietal polymicrogyria shares some features of the cobblestone brain malformation and demonstrate that loss of GPR56 leads to a dysregulation of the maintenance of the pial basement membrane integrity in the forebrain and the rostral cerebellum. In light of these findings and other data in the literature, this study aimed to refine the clinical features with the first description of a foetopathological case and to define the range of cobblestone-like features in GPR56 bilateral bifrontoparietal polymicrogyria in a sample of 14 patients. We identified homozygous GPR56 mutations in 14 patients from eight consanguineous families with typical bilateral bifrontoparietal polymicrogyria and in one foetal case, out of 30 patients with bifrontoparietal polymicrogyria referred for molecular screening. The foetal case, which was terminated at 35 weeks of gestation in view of suspicion of Walker Warburg syndrome, showed a cobblestone-like lissencephaly with a succession of normal, polymicrogyric and 'cobblestone-like' cortex with ectopic neuronal overmigration, agenesis of the cerebellar vermis and hypoplastic cerebellar hemispheres with additional neuronal overmigration in the pons and the cerebellar cortex. The 14 patients with GPR56 mutations (median 8.25 years, range 1.5-33 years) were phenotypically homogeneous with a distinctive clinical course characterized by pseudomyopathic behaviour at onset that subsequently evolved into severe mental and motor retardation. Generalized seizures (12/14) occurred later with onset ranging from 2.5 to 10 years with consistent electroencephalogram findings of predominantly anterior bursts of low amplitude α-like activity. Neuroimaging demonstrated a common phenotype with bilateral frontoparietally predominant polymicrogyria (13/13), cerebellar dysplasia with cysts mainly affecting the superior vermis (11/13) and patchy to diffuse myelination abnormalities (13/13). Additionally, the white matter abnormalities showed a peculiar evolution from severe hypomyelination at 4 months to patchy lesions later in childhood. Taken as a whole, these observations collectively demonstrate that GPR56 bilateral bifrontoparietal polymicrogyria combines all the features of a cobblestone-like lissencephaly and also suggest that GRP56-related defects produce a phenotypic continuum ranging from bilateral bifrontoparietal polymicrogyria to cobblestone-like lissencephaly.

Síndrome de Walker-Warburg / Walker-Warburg syndrome

A síndrome de Walker-Warburg (SWW) é uma doença autossômica recessiva rara, caracterizada por distrofia muscular congênita e associada a malformações cerebrais e oculares. Pode ser suspeitada ainda no pré-natal e o diagnóstico é firmado ao nascimento através de alterações clínicas e patológicas. O objetivo deste trabalho é relatar o caso de uma paciente com 3 meses de vida portadora de SWW. A SWW é uma síndrome severa e letal, diagnosticada através de quatro critérios: distrofia muscular congênita, anormalidades oculares, lissencefalia tipo II e malformação cerebelar. Seu tratamento visa apenas ao suporte e à prevenção de complicações. Pacientes com esta doença geralmente vão a óbito ainda no primeiro ano de vida

The Walker-Warburg syndrome (WWS) is a rare autosomal recessive disorder characterized by congenital muscular dystrophy and associated with cerebral and ocular malformations. It may be suspected even in the prenatal period and the diagnosis is made at birth through clinical and pathological characteristics. The aim of this study is to report the case of a 3-month-old with WWS. The WWS is a severe and lethal syndrome that is diagnosed by four criteria: congenital muscular dystrophy, ocular abnormalities, type II lissencephaly, and cerebellar malformation. Its treatment is only supportive and intended to prevent complications. Patients with this disease usually will die within the first year of life

Neurons generated from APP/APLP1/APLP2 triple knockout embryonic stem cells behave normally in vitro and in vivo: lack of evidence for a cell autonomous role of the amyloid precursor protein in neuronal differentiation.

Alzheimer's disease amyloid precursor protein (APP) has been implicated in many neurobiologic processes, but supporting evidence remains indirect. Studies are confounded by the existence of two partially redundant APP homologues, APLP1 and APLP2. APP/APLP1/APLP2 triple knockout (APP tKO) mice display cobblestone lissencephaly and are perinatally lethal. To circumvent this problem, we generated APP triple knockout embryonic stem (ES) cells and differentiated these to APP triple knockout neurons in vitro and in vivo. In comparison with wild-type (WT) ES cell-derived neurons, APP tKO neurons formed equally pure neuronal cultures, had unaltered in vitro migratory capacities, had a similar acquisition of polarity, and were capable of extending long neurites and forming active excitatory synapses. These data were confirmed in vivo in chimeric mice with APP tKO neurons expressing the enhanced green fluorescent protein (eGFP) present in a WT background brain. The results suggest that the loss of the APP family of proteins has no major effect on these critical neuronal processes and that the apparent multitude of functions in which APP has been implicated might be characterized by molecular redundancy. Our stem cell culture provides an excellent tool to circumvent the problem of lack of viability of APP/APLP triple knockout mice and will help to explore the function of this intriguing protein further in vitro and in vivo.

Abnormal fetal cerebral laminar organization in cobblestone complex as seen on post-mortem MRI and DTI.

We report a unique case of cobblestone complex using post-mortem MR and diffusion tensor imaging to assess the laminar organization of the fetal cerebrum. The imaging findings were correlated with autopsy findings. Abnormal cortical development in cobblestone complex resulted in disruption of normal laminar organization of the fetal brain, which was seen as interruption and nodularity of the high-signal T1 cortical band with increased anisotropy and medium diffusivity extending beyond the cortical band into the cerebral mantle on post-mortem MR and diffusion tensor imaging.