Autosomal recessive spinocerebellar ataxia with axonal neuropathy (ARSACS) is a neurodegenerative disorder characterized by juvenile onset of progressive cerebellar ataxia, axonal sensorimotor peripheral neuropathy, and increased serum alpha-fetoprotein. The objective of this study was to identify the molecular cause of disease in a consanguineous family from district Lakki Marwat, Khyber Pakhtunkhwa, Pakistan. A four-generation family with four affected siblings was enrolled, and whole exome sequencing was performed after ethical approval and informed consent from all family members. Clinical history was documented and blood samples were collected for DNA extraction. Whole exome sequencing revealed a previously known homozygous variant in the SETX gene (c.6694C>T; p.Arg2232Cys). Sanger sequencing validated the variant and confirmed autosomal recessive segregation within the family. In conclusion, this study confirms the utility of whole exome sequencing as a first-line molecular diagnostic tool in monogenic neurological disorders and underscores the importance of premarital genetic screening in consanguineous populations.