Acetylcholine receptor (AChR) deficiency is the most common form of congenital myasthenic syndrome (CMS). Most AChR deficiencies are caused by mutations in the coding region of the AChR epsilon subunit.¹ We report an Iranian Muslim family from the province of Eastern Azerbaijan (Maragheh) in which three of five offspring of consanguineous parents had early onset CMS arising from a newly described mutation in the epsilon subunit of the AChR; this mutation has been identified homozygously in all the three sibs. This is the first report of an AChR epsilon subunit mutation in Iran.

CASE PRESENTATION

The affected brother (case 1) was 23 years old and the affected sisters were 19 (case 2) and 16 (case 3) years old. The unaffected brother was 21 and the healthy sister was 13 years old. There was no history of miscarriage or infant mortality in the family, although, according to verbal accounts from the mother, fetal movements were decreased in all the affected sibs and case 1 had a difficult labour. The clinical diagnosis of CMS in this family had been made first in 1996. All cases presented with neonatal hypotonia, regurgitation, ptosis (case 1 developed ptosis at the age of 6 months), and delayed motor milestones. The course of the disease had been slowly progressive, transiently exacerbated by stress. Generalised weakness was more severe in the afternoons. Treatment with prednisone for …