[Analysis of clinical features and EBF3 gene variant in a child with hypotonia, ataxia and developmental delay].

Objective: To explore the genetic basis for a child featuring hypotonia, ataxia, and delayed development syndrome (HADDS).

Methods: Whole exome sequencing was carried out for the child. Candidate variant was verified by Sanger sequencing of the child and his parents.

Results: The child was found to harbor a de novo heterozygous c.625G>A (p.Arg209Trp) variant of the EBF3 gene, which has caused substitution of Arginine by Tryptophan. The variant may has impaired the binding affinity of EBF3 with DNA and altered its subcellular localization, and ultimately decreased the transcriptional activity of the EBF3 gene.

Conclusion: The c.625G>A variant of the EBF3 gene probably underlay the pathogenesis of HADDS in this child. Above finding has expanded the spectrum of EBF3 variants and enriched the clinical manifestations of the HADDS.