Objective:
To shed light on the role of TWNK gene mutations in familial myopathy
Background:
54-year-old female with history of hypertension and hypothyroidism who was evaluated for ptosis and muscle weakness. Symptoms started in her teens with ptosis and imbalance due to weakness. Her weakness was first noted in 2016. The patient developed swallowing and breathing difficulties over the course of several years. Of note, she reported a history of prolonged duration of recovery from anesthesia during cholecystectomy. Recently, she started having autonomic features including postural hypotension. The course of the disease is slowly progressive and there are several family members who are affected with a similar range of symptoms including ptosis and muscle weakness.
Results:
Electromyography was significant for myopathic processes involving facial, proximal upper extremities and distal lower extremities. Anti-Acetylcholine Receptor (anti-AChR) antibody were negative. Genetic testing revealed AD/R C 1087 T>C, heterozygous via GeneDx which was labeled as a variant of unknown significance for TWNK related disorder. Of note, her brother with similar symptoms tested positive for the same genetic variant making this mutation a pathogenic one instead of a variant of unknown significance. The patient’s ptosis and myopathy continue to get worse. She is on coenzyme Q10 and carnitine for symptomatic management.
Conclusions:
TWNK gene mutations were reported in the past to be associated with multiple neurologic entities ranging from neuropathy to ataxia and progressive ophthalmoplegia which are consistent with an autosomal recessive inheritance. We are reporting a case of ptosis and myopathy that is associated with autonomic features that is likely to be due to pathogenic TWNK gene mutation that is following an autosomal dominant inheritance. Identifying such cases would help understand future management of such cases appropriately.