Quinine-responsive muscle cramps in X-linked bulbospinal muscular atrophy Kennedy

Abstract

Letter to the editor X-linked bulbo-spinal muscular atrophy (BSMA, Kennedy disease) is a rare motor- neuron-disease due to a CAGrepeat expansion in the androgen-receptor-gene on Xq12 [1, 2]. BSMA presents clinically with slowly progressive, amyotrophic quadruparesis, bulbar involvement, wasting, fasciculations, and gynecomastia. Muscle cramps are not infrequent in BSMA [3] but therapy is usually ineffective. The patient is a 39-year-old male with a history of postural tremor since age 12 years, dysarthria since age 15 years ubiquitous muscle cramps since age 29 years, prohibiting sleep and increasing since age 36 years, general myalgias since age 32 years, general fasciculations predominantly of the thighs since age 34 years, myoclonic jerks and dyspnea upon exercise since age 36 years, and easy fatigability upon exercise. Symptoms worsened during episodic relapses 3–4 times/year, each lasting 2–3 weeks. The family history was positive for tremor (grandfather and uncle from the mother’s side, brother), and for his other presenting symptoms (uncle from the mother’s side). The patient’s mother was symptom-free. Clinical neurologic examination at age 39 years showed dysarthria, fibrillations of the tongue, weakness of the facial muscles, weakness of head anteflexion (M5-), diffuse weakness of both upper-limbs with proximal and rightsided predominance (M4 to M5-), reduced tendon reflexes, fasciculations and myoclonic jerks on the lower-limbs, predominantly of the thighs. There was discrete wasting of the upper- and distal lower-limbs.