Mowat-Wilson syndrome in a fetus with antenatal diagnosis of short corpus callosum: advocacy for standard autopsy

Hypoplasia of the Corpus Callosum: A Single Center Experience and a Concise Literature Review

AimCorpus callosum hypoplasia is described as a fully formed corpus callosum with reduced thickness. Our purpose is to evaluate the current knowledge about this anomaly including it's effect on the neurodevelopmental outcome and to report our single center experience. Methods: PubMed, Medline and reference lists were searched using combinations of these terms: "Hypoplasia of corpus callosum and prenatal diagnosis" and "neurodevelopmental outcome". Results: Eleven studies were included, with a final population of 48 patients (45 cases from literature plus 3 of our own cases). Hypoplasia of the corpus callosum was detected by ultrasound scan alone in 77% of cases: magnetic resonance confirmed the ultrasound suspicion in the remaining 23% of cases. Isolated form was detected in 31% cases. Adverse fetal outcomes occurred in 62% of cases, while 38% of cases were born alive. The neurodevelopmental outcome was found to be normal in 33% of cases. Conclusion: Antenatal detection of corpus callosum hypoplasia remains challenging. Counseling is difficult because neurodevelopmental outcomes are variable.

Prenatal Imaging Features and Postnatal Outcome of Short Corpus Callosum: A Series of 42 Cases

OBJECTIVES

Our goal was to provide a better understanding of isolated short corpus callosum (SCC) regarding prenatal diagnosis and postnatal outcome.

METHODS

We retrospectively reviewed prenatal and postnatal imaging, clinical, and biological data from 42 cases with isolated SCC.

RESULTS

Prenatal imaging showed SCC in all cases (n = 42). SCC was limited to rostrum and/or genu and/or splenium in 21 cases, involved body in 16 cases, and was more extensive in 5 cases. Indirect imaging features included typical buffalo horn ventricles (n = 14), septal dysmorphism (n = 14), parallel lateral ventricles (n = 12), and ventriculomegaly (n = 4), as well as atypical features in 5 cases. SCC was associated with interhemispheric cysts and pericallosal lipomas in 3 and 6 cases, respectively. Aneuploidy was found in 2 cases. Normal psychomotor development, mild developmental disorders, and global developmental delay were found in 70, 15, and 15% of our cases, respectively.

CONCLUSIONS

SCC should be investigated to look for pericallosal lipoma and typical versus atypical indirect features of corpus callosum agenesis (CCA). Prenatal counselling should be guided by imaging as well as clinical and genetic context. Outcome of patients with SCC was similar to the one presenting with complete CCA.

Neuropathology of genetically defined malformations of cortical development-A systematic literature review

AIMS

Malformations of cortical development (MCD) include a heterogeneous spectrum of clinical, imaging, molecular and histopathological entities. While the understanding of genetic causes of MCD has improved with the availability of next-generation sequencing modalities, genotype-histopathological correlations remain limited. This is the first systematic review of molecular and neuropathological findings in patients with MCD to provide a comprehensive overview of the literature.

METHODS

A systematic review was performed between November 2019 and February 2020. A MEDLINE search was conducted for 132 genes previously linked to MCD in order to identify studies reporting macroscopic and/or microscopic findings in patients with a confirmed genetic cause.

RESULTS

Eighty-one studies were included in this review reporting neuropathological features associated with pathogenic variants in 46 genes (46/132 genes, 34.8%). Four groups emerged, consisting of (1) 13 genes with well-defined histological-genotype correlations, (2) 27 genes for which neuropathological reports were limited, (3) 5 genes with conflicting neuropathological features, and (4) 87 genes for which no histological data were available. Lissencephaly and polymicrogyria were reported most frequently. Associated brain malformations were variably present, with abnormalities of the corpus callosum as most common associated feature.

CONCLUSIONS

Neuropathological data in patients with MCD with a defined genetic cause are available only for a small number of genes. As each genetic cause might lead to unique histopathological features of MCD, standardised thorough neuropathological assessment and reporting should be encouraged. Histological features can help improve the understanding of the pathogenesis of MCD and generate hypotheses with impact on further research directions.

Neuropathology of Mowat-Wilson Syndrome

Mowat-Wilson syndrome (MWS) is a syndromic form of Hirschsprung disease that is characterized by variable degrees of intellectual disability, characteristic facial dysmorphism, and a diverse set of other congenital malformations due to haploinsufficiency of ZEB2. A variety of brain malformations have been described in neuroimaging studies of MWS patients, and the role of ZEB2 in the brain has been studied in a multitude of genetically engineered mouse models that are now available. However, a paucity of autopsy information limits our ability to correlate data from neuroimaging studies and animal models with actual MWS patient tissues. Here, we report the autopsy neuropathology of a 19-year-old male patient with MWS. Autopsy neuropathology findings correlated well with the reported MWS neuroimaging data and are in keeping with data from genetically engineered MWS mouse models. This autopsy enhances our understanding of ZEB2 function in human brain development and demonstrates the reliability of MWS murine models.

Fetal diagnosis of Mowat-Wilson syndrome by whole exome sequencing

Mowat-Wilson syndrome (MWS) is a complex genetic disorder associated with heterozygous variation in ZEB2. It is mainly characterized by moderate-to-severe intellectual disability, facial dysmorphism, epilepsy, and various malformations including Hirschsprung disease, corpus callosum anomalies, and congenital heart defects. It is rarely diagnosed prenatally and there is limited information available on the prenatal phenotype associated with MWS. Here we report the detection of a heterozygous de novo nonsense variant in ZEB2 by whole exome sequencing in a fetus with microphthalmia in addition to cardiac defects and typical MWS facial dysmorphism. As the prenatal phenotypic spectrum of MWS expands, the routine addition of fetal genomic testing particularly in the presence of multiple malformations will increase both the sensitivity and specificity of prenatal diagnostics.

[Clinical and genetic features of Mowat-Wilson syndrome: an analysis of 3 cases]

Mowat-Wilson syndrome (MWS) is a rare autosomal dominant genetic disease caused by zinc finger E-box-binding homeobox 2 (ZEB2) gene mutation and has various clinical manifestations including intellectual disability/global developmental delay, unusual facies and multiple congenital malformations. This article reports the clinical features and gene mutations of three children diagnosed with MWS by ZEB2 gene analysis. All three children had Hirschsprung disease and unusual facies. One child died of severe heart failure and pneumonia at the age of 4 months. Global developmental delay was not discovered by her parents due to her young age. The other two children had severe global developmental delay. All three children carried a de novo heterozygous nonsense mutation in the ZEB2 gene, among which c.756C>A (p.Y252X) had not been reported before. Such mutations produced truncated proteins and were highly pathogenic. MWS is presented with strong clinical and genetic heterogeneity. Clinicians should consider the possibility of MWS when a child has unusual facies of MWS, intellectual disability/global developmental delay and multiple congenital malformations. Gene detection helps to make a confirmed diagnosis.

Experience of Mowat-Wilson syndrome prenatal diagnosis for a Chinese family

Mowat–Wilson syndrome (MWS) is a complex developmental disorder. We report the first prenatal diagnosis provided for a family in mainland China after identifying the causal mutation for the proband. Special focus on MWS‐related organs during prenatal ultrasound scan is described which is extremely important for genetic counseling of parents.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Polymicrogyria in a 10-month-old boy with Mowat-Wilson syndrome

Mowat-Wilson syndrome (MWS, OMIM# 235730) is a multiple congenital anomaly disorder characterized by intellectual disability, seizures, microcephaly, and distinct facial features. Additional findings include structural brain abnormalities, eye defects, congenital heart defects, Hirschsprung disease (HSCR), and genitourinary anomalies. It is caused by de novo heterozygous mutations or deletions of the ZEB2 gene on chromosome 2q21-q23. We report here on a 10-month-old boy with typical features of MWS who presented with the novel finding of polymicrogyria on brain magnetic resonance imaging. We also review the current literature regarding central nervous system anomalies in MWS.

Retrospective analysis of prenatal ultrasound of children with Hirschsprung disease

OBJECTIVE

Hirschsprung disease (HD) is a rare gastrointestinal disorder. Our aim was to study the prenatal ultrasound findings of children who were diagnosed with HD after birth.

METHODS

The study population included children who suffered from HD between 1990 and 2008. Data of anomaly scan findings in prenatal ultrasound, demographic and post-natal physical abnormalities and treatment were retrieved from medical files and interviews with the parents.

RESULTS

Twenty-two patients confirmed histopathological diagnosis of HD at age of 1 day to 15 months. Nineteen fetuses had anomaly scan during pregnancy, which revealed minor sonographic abnormalities in three fetuses; two of them had hyperechogenic bowel. One fetus with hyperechogenic bowel had polyhydramnion, and another had a family history of three brothers with HD. A third fetus had dilated pelvic kidney. None of them had sonographic evidence of bowel dilatation. After birth, six patients (31%) were found to have other structural anomalies: ventriculoseptal defect, atriseptal defect, atrio-ventricular septal defect, and pyloric stenosis.

CONCLUSIONS

Abnormal sonographic findings of fetal bowel are absent in the vast majority of fetuses who are diagnosed with HD after birth. In women with a family history of HD, a third trimester anomaly scan may be warranted.