Spinocerebellar Ataxia Type 35 Presenting with Dysphagia in a Patient from Saudi Arabia: A Case Report and Literature Review.

Mutations in the transglutaminase 6 gene (TGM6) are associated with spinocerebellar ataxia type 35 (SCA35), and cases have been reported across diverse ethnic groups. We report the first documented case of SCA35 in Saudi Arabia, together with a focused literature review. A 35-year-old Saudi man presented to a neurology clinic with severe gait instability following nonspecific symptoms, including unintentional weight loss, dysphagia, abdominal pain, and intermittent diplopia. No family history of ataxia or similar neurological disease was noted. The condition progressed with neuropsychiatric manifestations (adjustment disorder, generalized myalgia, fibromyalgia) and upper motor neuron and extrapyramidal signs. He was admitted for further evaluation. A comprehensive diagnostic work-up, including cerebrospinal fluid studies, multiplex polymerase chain reaction, and nerve conduction studies, ruled out celiac disease, Wilson's disease, and demyelinating diseases. Brain and full-spine magnetic resonance imaging showed no cerebellar atrophy or spinal cord abnormalities. Whole-exome sequencing identified a heterozygous splice-site mutation in TGM6 (c.850 + 1G > A), consistent with autosomal dominant SCA35. To our knowledge, this is the first reported case of SCA35 in the Middle East. This case underscores the challenges in diagnosing this condition, as patients may present with atypical features, such as dysphagia. Our findings enhance the current understanding of the epidemiology, clinical manifestations, and genetic landscape of SCA35 to improve the diagnosis and management of this rare disorder.