Mowat-Wilson syndrome: deafness in the first Egyptian case who was conceived by intracytoplasmic sperm injection

A Chinese Boy with Mowat-Wilson Syndrome Caused by a 10 bp Deletion in the ZEB2 Gene

Purpose

Mowat–Wilson syndrome (MWS) is a rare complex malformation syndrome which is characterized by typical facial dysmorphism, moderate to severe intellectual disability, global developmental delay, and multiple congenital anomalies. Here, we summarize the clinical characteristics and gene mutation analysis of a Chinese boy with MWS.

Patients and Methods

The clinical features of the patient were monitored. DNA extracted from peripheral blood was subjected to sequencing analysis. Then, the whole-exome sequencing was performed.

Results

A novel deletion mutation (c.1137_1146del TAGTATGTCT) was identified in exon 8 of the ZEB2 gene. The deletion mutation was predicted to produce a truncated protein (p.S380Nfs*13), resulting in haploinsufficiency. The patient presented with short stature, microcephaly, congenital heart defects, cryptorchidism, corpus callosum agenesis, global developmental delay, and intellectual disability. Furthermore, he demonstrated bilateral sensorineural hearing loss. This manifestation is less common in MWS. It is first reported in Chinese patients with MWS. Clinical follow-up showed that the facial features of MWS developed with time. The facial features of the patient were not obvious except for the uplifted ear lobes at the age of 3 months. At the age of 22 months, the facial characteristics of the patient included ocular hypertelorism, frontal bossing, rounded nasal tip, sparse eyebrows, prominent chin, widely spaced teeth, and uplifted ear lobes with a central depression.

Conclusion

A novel deletion mutation of the ZEB2 gene was identified. This work contributes to expanding the mutation spectra of MWS. Our results may reflect the variability of the phenotype in MWS.

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Chudley–McCullough Syndrome: Case Report and the Role of Neuroimaging to Suggest the Diagnosis

Chudley–McCullough syndrome (CMS) is an autosomal recessive condition first described in 1997. The most striking features of this syndrome include sensorineural hearing loss, craniofacial disproportion, and brain abnormalities such as agenesis of the corpus callosum, polymicrogyria, ventriculomegaly, and changes in cerebellar architecture. We describe the case of a 2-year-old patient with CMS confirmed by genetic testing (GPSM2 gene mutation), who presented with global developmental delays and characteristic neuroimaging features including arachnoid cysts, agenesis of the corpus callosum, cerebellar dysplasia, and frontal heterotopia. Early recognition of this rare clinical syndrome may reduce the diagnostic odyssey and ultimately improve the quality of life for affected children. This report will focus on unique clinical and radiographic features of CMS.

Interstitial Deletion of 2q22.2q22.3 Involving the Entire ZEB2 Gene in a Case of Mowat-Wilson Syndrome

Mowat-Wilson syndrome (MWS) is a rare autosomal dominant syndrome characterized by dysmorphic features, mental retardation, and congenital heart disease (CHD). MWS results from microdeletions of chromosome 2q23 or de novo SNVs involving the ZEB2 gene. Here, we report on an Egyptian MWS patient diagnosed by chromosomal microarray (CMA). A 1-year-old male child was referred to the CHD clinic, National Research Centre, presenting with dysmorphic features and CHD. The patient was referred to the human cytogenetics department for cytogenetic analysis and for screening of subtelomere rearrangements and microdeletion loci, using MLPA, and all revealed normal results. CMA revealed an interstitial 2.27-Mb microdeletion in chromosome 2q, involving the entire ZEB2 gene and other genes. This study emphasizes the significance of CMA in the detection of microdeletions/microduplications and as a screening tool in cases presenting with CHD and extracardiac manifestations. MWS should be suspected in patients presenting with the characteristic facial dysmorphism, developmental delay, seizures, Hirschsprung disease, and congenital heart anomalies, especially those involving the pulmonary arteries or pulmonary valves. It is recommended to include the ZEB2 locus in the MLPA microdeletions probes.

Chudley-McCullough Syndrome: A Recognizable Clinical Entity Characterized by Deafness and Typical Brain Malformations

Chudley-McCullough syndrome, a rare autosomal recessive disorder due to pathogenic variants in the GPSM2 (G-protein signaling modulator 2) gene, is characterized by early-onset sensorineural deafness and a typical combination of brain malformations, including ventriculomegaly, (partial) agenesis of the corpus callosum, cerebellar dysplasia, arachnoid cysts, frontal subcortical heterotopia, and midline polymicrogyria. When hearing loss is managed early, most patients have minor or no impairment of motor and cognitive development, despite the presence of brain malformations. We report 2 cases of Chudley-McCullough syndrome, one presenting with congenital deafness and normal development except for speech delay and one presenting prenatally with ventriculomegaly and an atypical postnatal course characterized by epileptic spasms, deafness, and moderate intellectual disability. These highlight the challenges faced by clinicians when predicting prognosis based on pre- or postnatal imaging of brain malformations. We have also reviewed the phenotype and genotype of previous published cases to better understand Chudley-McCullough syndrome.

Abnormal methylation of spermatozoa induced by benzo(a)pyrene in rats

Epigenetic mutations caused by pollutants are possibly linked to many diseases. Benzo(a)pyrene (BaP) is one of the most representative air pollutants and has aroused wide concern because of its strong carcinogenicity. The reproductive toxicity induced by BaP has been identified, but little is known about the characteristics of the methylation changes induced by BaP. In this study, a methylated DNA immunoprecipitation sequencing method was used to detect the methylation of sperm DNA of rats exposed to BaP. Compared with the respective genes in normal rats, there were 3227 hypomethylated genes and 828 hypermethylated genes after BaP exposure. Gene ontology enrichment analysis reported that differentially methylated genes (DMGs) were enriched in the localization, single-multicellular organism process and plasma membrane. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the DMGs were significantly enriched in the Ras signalling pathway, Rap1 signalling pathway, pancreatic secretion and neuroactive ligand-receptor interaction. DisGeNET disease spectrum analysis showed that DMGs were associated with infertility and certain genetic diseases. Further research needs to be done to explore whether these abnormal methylation are transgenerational.

Hirschsprung's disease in children with Mowat-Wilson syndrome

BACKGROUND

Hirschsprung's disease (HSCR) is cited as a classical component in the constellation of features found in children with Mowat-Wilson syndrome (MWS), which is caused by a mutation of the ZEB2 gene. The prevalence and phenotype of HSCR in those with MWS has yet to be determined. Similarly, it is not known if children with MWS who undergo a curative pull-through operation experience similar functional outcomes. We aimed to delineate the clinical features of those with MWS and HSCR and to determine if these patients experience unfavourable outcomes following pull-through surgery.

METHODS

A systematic review of the literature using the key search term "Mowat Wilson" was performed using three online databases. Clinical data were collected on all patients with a diagnosis of MWS confirmed by ZEB2 analysis. Data regarding bowel function in children with biopsy-proven HSCR were recorded where available. Statistical analysis was performed using SPSS (v. 20.0).

RESULTS

Fifty-two articles were reviewed in the final analysis, incorporating data on 256 patients with a diagnosis of MWS. HSCR was diagnosed in 111 patients (43.4%). Males with HSCR had a slightly increased risk of genital tract anomalies (e.g. hypospadias) compared to those without HSCR (RR 1.79, p = 0.05). Data pertaining to disease phenotype and functional outcome were only available on 42 and 13 patients, respectively. Rectosigmoid aganglionosis was the most common sub-type of HSCR, being described 26 patients (66.7%), albeit accounting for a lower proportion than would normally be expected in an HSCR population. Only two patients (15.4%) were described as having normal bowel function at follow-up with the remainder having terminal stomas, or experiencing troublesome persistent bowel symptoms and recurrent enterocolitis.

CONCLUSION

Hirschsprung's disease is present in approximately 45% of patients diagnosed with MWS. Although there is a relative lack of data available on the clinical phenotype of HSCR in this group and their functional outcome following pull-through operation, our data suggest an increased prevalence of long-segment aganglionosis and an increased risk of clinically significant persistent bowel symptoms following pull-through surgery, in many cases necessitating terminal stoma formation.