Fig. 45.1
Images of Patient (a) Face: demonstrates the small jaw, broad based nose, low set ears and epicanthic folds. (b) Hands: clinodactyly of fifth digits (c) Feet: syndactyly of second, third and fourth toes
Investigations
She had a mildly elevated CK 251 IU (<200). Potassium levels were normal. An ECG showed ventricular bigeminy, long QTc and U waves (Fig. 45.2). EMG was normal. The long exercise test (McManis) was positive and showed a 71 % decrement in CMAP over 50 min (Fig. 45.3). Sodium (SCN4A) and Calcium (CACNA1S) channel testing were normal. Potassium channel testing (KCNJ2) showed the mutation R218W.
Fig. 45.2
ECG: Shows ventricular bigeminy, long QTc and U waves
