[Analysis of KIF1A gene variant in a Chinese pedigree affected with Spastic paraplegia type 30]

To explore the genetic basis for a Chinese pedigree affected with hereditary spastic paraplegia type 30 (HSP30).

A proband presented at the Second Hospital of Shanxi Medical University in August 2021 was selected as the study subject. The proband was subjected to whole exome sequencing, and candidate variant was verified by Sanger sequencing and bioinformatic analysis.

The proband was found to have harbored a heterozygous c.110T>C variant in exon 3 of the KIF1A gene, which can cause substitution of isoleucine by threonine at position 37 (p.I37T) and alter the function of its protein product. The same variant was not found in his parents, elder brother and elder sister, suggesting that it has a de novo origin. Based on the guidelines of the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic (PM2_Supporting+PP3+PS2).

The c.110T>C variant of the KIF1A gene probably underlay the HSP30 in the proband. Above finding has enable genetic counseling for this family.