Objective: To explore the clinical characteristics and genetic basis of a child with Teebi hypertelorism syndrome 1 (TBHS1).
Methods: A child with TBHS1 who was admitted to the Children's Medical Center Affiliated to Shanghai Jiao Tong University School of Medicine on July 13, 2021 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing and bioinformatic analysis.
Results: The child, a 13-year-old male, had manifested delayed growth and development. WES results revealed that he has harbored a heterozygous c.1244A>G variant of the SPECC1L gene, which was verified to be de novo in origin. The variant has not been included in the HGMD and gnomAD databases. As predicted by online software including PolyPhen-2, SIFT, and Mutation Taster, the variant may affect the function of protein domain. And PyMOL software has predicted that the structural stability of SPECC1L protein (p.Gln415Arg) might be reduced. Based on the guidelines of the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PM6+PM1+PP4+PM2_Supporting+PP3).
Conclusion: The heterozygous c.1244A>G variant of the SPECC1L gene probably underlay the TBHS1 in this child. Above finding has expanded the genotypic and phenotypic spectrum of the SPECC1L gene and provided a basis for the clinical diagnosis of this child.