Report of a Turkish girl with Andersen-Tawil syndrome

Abstract

The case is a 9-year-old girl with a history of syncope attacks for 6 years and recurrent paraplegia attacks for 1.5 years. She was diagnosed with epilepsy and was given valproate for the attacks, but no improvement was noted. Because of her paraplegia attacks, lasting between a few hours and 3 days, abnormal findings she was diagnosed with conversion. Her prenatal, natal and postnatal history was unremarkable, and her school performance was high. There was a close consanguinity between the parents. She had four healthy sibs. Her mother, maternal uncle and maternal grandmother had intermittent fatigue, numbness on the extremities. On physical examination, she had mild elongated face and dysmorphic changes on the hands. Muscle strength was normal on the upper extremities, but no muscle activity was noted on the lower extremities. She also had no response to touch and pain stimuli on the lower extremities. On laboratory investigation, serum electrolytes including potassium level, renal and liver function tests were normal. Glomerul filtration rate was 59 mL/min/m². QTc interval was mild prolonged (0.45 seconds). Electromyographic examination was unremarkable. On DNA mutation analysis, no mutation of KCJN2 gene coding for Kir 2.1 protein was diagnosed. Her mother had normal serum electrolytes, but had prolonged QTc interval (0.46 seconds). Her father was completely normal for serum electrolytes and electrocardiographic examination. Unfortunately, maternal uncle and grandmother could not be examined. Based on the clinical and laboratory abnormalities she was diagnosed with Andersen-Tawil syndrome and given potassium supplementation. Her paraplegia and syncope attacks were markedly decreased after initiating potassium therapy. Now, she is in the 3rd year of follow-up. She is continued to use potassium and her paraplegia and syncope attacks noted only one attack a 2–3 months.

Keywords

Andersen-Tawil syndrome - paraplegia - syncope - prolonged QTc interval