Elevated creatine kinase and transaminases in asymptomatic SBMA

Area of Science:

• Neurology
• Genetics
• Biochemistry

Background:

• X-linked spinal and bulbar muscular atrophy (SBMA), also known as Kennedy's disease, typically manifests in adulthood.
• Prognosis for SBMA is variable, with symptom onset usually in the fourth or fifth decade.
• Elevated serum creatine kinase (CK) is a known marker in clinically apparent SBMA patients.

Observation:

• This report details two male patients with SBMA.
• These patients exhibited elevated serum transaminases and CK levels approximately ten years before the onset of typical SBMA symptoms.
• These enzyme elevations were initially considered 'idiopathic'.

Findings:

• SBMA can present with elevated serum CK and transaminases years before clinical symptoms appear.
• This suggests that biochemical changes may precede the neurological manifestations of the disease.
• The androgen receptor (AR) gene CAG trinucleotide repeat expansion is the underlying genetic cause of SBMA.

Implications:

• Consider SBMA in males presenting with unexplained elevations in serum CK and transaminases.
• Early genetic testing for the AR CAG expansion should be considered in such cases.
• This may lead to earlier diagnosis and potential future therapeutic interventions for SBMA.