Clinical phenotype and gene variation analysis of MED25 gene mutation induced Basel-Vanagaite-Smirin-Yosef syndrome / 中华神经科杂志

ABSTRACT

Objective:To investigate the clinical phenotype and genetic variation of Basel-Vanagaite-Smirin-Yosef syndrome (BVSYS), and to enhance clinicians′ knowledge of the disease.Methods:The clinical data of a child with BVSYS admitted to the Department of Neurological Rehabilitation, Qingdao Women and Children′s Hospital Affiliated to Qingdao University in February 2023 were collected. Whole genome sequencing was used to analyze the pathogenic genes of the child, and Sanger sequencing was used to verify the suspected mutation sites of the family members. The clinical phenotype and genetic variation characteristics were analyzed, and the clinical characteristics of BVSYS were summarized in combination with relevant literature.Results:The patient, a female aged 3 years and 1 month, presented with global developmental delay, speech disorder, distinctive facial features, esotropia, epilepsy, hypotonia and atrial septal defect. Brain magnetic resonance imaging revealed bilateral ventriculomegaly with abnormal signal intensity in the posterior bodies of both lateral ventricles and thinning of the corpus callosum. The whole genome sequencing revealed a homozygous missense mutation c.518 (exon5) T>C (p.IIe173Thr) in the MED25 gene of the child, and Sanger sequencing confirmed that her parents and elder brother carried the aforementioned heterozygous mutation, which was classified as a likely pathogenic mutation according to the guidelines of the American College of Medical Genetics and Genomics. A total of 22 cases from 6 literature sources were retrieved, with no reported cases in China so far. Conclusions:BVSYS is clinically rare. For patients presenting with unexplained global developmental delay or intellectual disability combined with craniofacial, neurological, cardiac, and eye abnormalities, targeted genetic testing can facilitate a definite diagnosis.