Genetic analysis of a child with Complex cortical dysplasia with other brain malformations type 6 due to a p.M73V variant of TUBB gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with multiple malformations.@*METHODS@#A child who had presented at Shanxi Provincial Children's Hospital in February 2021 was selected as the study subject. Clinical data of the patient was collected, and whole exome sequencing (WES) was carried out to screen pathogenic variants associated with the phenotype. Candidate variant was validated by Sanger sequencing of her family members.@*RESULTS@#The child had normal skin, but right ear defect, hemivertebral deformity, ventricular septal defect, arterial duct and patent foramen ovale, and separation of collecting system of the left kidney. Cranial MRI showed irregular enlargement of bilateral ventricles and widening of the distance between the cerebral cortex and temporal meninges. Genetic testing revealed that she has harbored a heterozygous variant of NM_178014.4: c.217A>G (p.Met73Val) in the TUBB gene, which was unreported previously and predicted to be likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). The child was diagnosed with Complex cortical dysplasia with other brain malformations 6 (CDCBM6).@*CONCLUSION@#CDCBM is a rare and serious disease with great genetic heterogeneity, and CDCBM6 caused by mutations of the TUBB gene is even rarer. Above finding has enriched the variant and phenotypic spectrum of the TUBB gene, and provided important reference for summarizing the genotype-phenotype correlation of the CDCBM6.

Phenotypic and genetic analysis of a child featuring multiple malformations due to copy number variation on chromosome 5 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the origin of chromosomal aberration for a child featuring multiple malformation, and to correlate the genotype with phenotype.</p><p><b>METHODS</b>Routine G-banding was performed to analyze the karyotype of the patient and her parents, and array comparative genomic hybridization (array CGH) was used for fine mapping of the aberrant region.</p><p><b>RESULTS</b>The karyotype of the child was ascertained as 46,XY. Array CGH has mapped a 14.21 Mb deletion to 5p15.2p15.33, and a very small 3.67 Mb duplication to 5q35.3. The patient has presented features such as mental retardation, heart defect, low-set ears, hypertelorism and down-slanting palpebral fissures.</p><p><b>CONCLUSION</b>Chromosome 5 copy number variation can cause multiple malformation. In contrast to routine karyotype analysis, array CGH can map aberrant region with much higher resolution and accuracy.</p>