Hypergonadotropic hypogonadism in spinocerebellar ataxia type 2: a case report

The association between cerebellar ataxia and hypogonadism is seen rarely and is not well recognized. Spinocerebellar ataxia (SCA) is an autosomal dominantly inherited, progressive ataxia disorder, and SCA type 2 (SCA2) characteristically presents with a highly variable phenotype with multisystemic involvement. Although the clinical spectrum of SCA2 is broad, hypogonadism has not been reported as an accompanying symptom.

To report a case study that describes hypergonadotropic hypogonadism as a non-neurological manifestation of cerebellar ataxia in a patient with a hereditary trinucleotide repeat expansion disorder, SCA2.

Case report of a man admitted to an academic medical center.

A 45-year-old man with a history of azoospermia in work-up for infertility was admitted for evaluation of a left-side hand tremor, instability on walking and impaired balance. Upon physical examination, the patient had a micropenis about 3 cm in length and had decreased testicular size (12 cc each) on orchidometry, but normal secondary sexual characteristics and average stature. Laboratory tests showed the presence of hypergonadotropic hypogonadism. A brain magnetic resonance imaging scan showed marked atrophy involving both the cerebellum and pons. Genetic analysis for hereditary ataxia demonstrated the presence of a 37 CAG triplet expansion in the mutated allele (genotype 22/37) in the SCA2 gene, confirming the diagnosis of SCA2.

The present study suggests that a common genetic implication may be shared between these neurologic and non-neurologic signs, and there may be various associations between these heterogeneous manifestations. The clinical spectrum of the SCA2 should be widened, and further data collection is needed to elucidate the relationship among the clinical manifestations.