A Novel Pathogenic Mutation in WNK1 Gene Causing HSAN Type II in Three Siblings

Hereditary sensory and autonomic neuropathy (HSAN) is a rare genetic disorder that primarily affects the peripheral nervous system, leading to a progressive loss of the ability to perceive pain, temperature, and touch. This condition can result in severe complications, including injuries and infections due to the inability to feel pain. HSAN is classified into nine types, with types I and VII exhibiting autosomal dominant inheritance, while the others follow an autosomal recessive pattern. In this study, we examined three affected brothers of Turkish Azeri descent, aged 20, 23, and 25 years. They presented symptoms such as a lack of temperature and pain sensation, frequent wounds and infections, self-harm, and hyperkeratosis. To identify the genetic cause of their condition, whole-exome sequencing (WES) was performed, followed by Sanger sequencing to confirm the findings. The results revealed a homozygous likely pathogenic nonsense mutation, c.2971C > T (p.Arg991Ter), in exon 9 of the WNK1 gene. This mutation results in the truncation of three isoforms of the WNK1 protein, which are essential for pain perception. This discovery enhances our understanding of HSAN and highlights the importance of genetic testing for accurate diagnosis and future screening.