A novel DOK7 mutation causing limb-girdle congenital myasthenic syndrome

We report a case series of 5 Latino patients with limb-girdle pattern weakness, four patients are sisters, with one patient unrelated. Repetitive nerve stimulation showed a significant decrement in all cases. Targeted genetic testing for congenital myasthenic syndromes demonstrated a known DOK7 pathogenic mutation in each case, and in all five cases also revealed a novel DOK7 missense mutation in exon 7 with c.94G>A; providing strong evidence this mutation is pathogenic. DOK7-related congenital myasthenic syndrome often lacks oculobulbar involvement, and may present with limb-girdle weakness, mimicking limb-girdle muscular dystrophy.