[Clinical and genetic analysis of a child with Lamb-Shaffer syndrome due to a de novo variant of SOX5 gene].

Objective: To explore the clinical features of a child with Lamb-Shaffer syndrome (LAMSHF) due to a variant of SOX5 gene.

Methods: A child who was admitted to Children's Hospital Affiliated to Zhengzhou University in July 2022 was selected as the study subject. Clinical data of the child was collected. Whole exome sequencing (WES) was carried out on peripheral blood samples from the child and his parents, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. The study has been approved by the Medical Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No. 2024-K-100).

Results: The child, an one-year-and-seven-month-old male, has manifested delayed development in speech and language, intelligence and movement, in addition with mild facial deformities and eye signs. Whole exome sequencing revealed that he has harbored a heterozygous c.1828_1829insGACT (p.Y610fs*1) frameshifting variant of the SOX5 gene. Sanger sequencing confirmed the variant to be de novo in origin. The variant was also unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PVS1+PS2+PM2_supporting).

Conclusion: The c.1828_1829insGACT (p.Y610fs*1) variant of the SOX5 gene probably underlay the pathogenesis of LAMSHF in this child. For children with delayed mental, language, intellectual, and motor development, genetic testing should be conducted to facilitate early diagnosis. Above finding has enriched the mutational spectrum of the SOX5 gene.