Spinocerebellar ataxia 2 in a family with different phenotypes: Two case reports

RATIONALE: Spinocerebellar ataxia 2 (SCA2) is a genetic disease, mainly characterized by ataxia. A number of other neurological symptoms also have been described, such as Parkinsonism, cognitive dysfunction, autonomic dysfunction, even the signs of motor neuron disease and so on. Mostly, In the same family, clinical performance is the same in most cases. Here, we describe a father and his son who suffered from SCA2, but their first manifestations were different. PATIENT CONCERNS: The father exhibited progressive bradykinesia and rigidity, which resulted in the dysfunction of walking and caring himself. He hoped to relieve his symptoms by taking medicine. But the son presented with ataxia which was mild that the discomfort did not affect his daily life with none treated. DIAGNOSIS: Both of them were given SCA2 tests. Briefly, we designed primers around the CAG trinucleotide, repeated the spinal cerebellar ataxia subtype gene, performed PCR expansion, and then calculated the specific number of repetitions by capillary electrophoresis. Abnormal expansion was detected in them through SCA2 sequencing with different repeat numbers of CAG, and then they were diagnosed with SCA2 sequencing. INTERVENTIONS: The father was treated with dopaminergic drugs, but the son was not administered treatment. OUTCOMES: The father's symptoms are improved and he can take care of himself. The son has none difficulty in his daily life. LESSONS: It is rare that different individuals in the same family with SCA2 have different manifestations. The genetic testing is a crucial method to diagnose the disease of SCA2.