APTX and cardiofaciocutaneous syndrome: The secondary forms are probably more frequent, and they include patients with ataxia and oculomotor apraxia due to mutations in the aprataxin (APTX) gene [66,67,68]; with isolated myopathy due to mutations in the electron-transferring-flavoprotein dehydrogenase gene (ETFDH) [69]; and with cardiofaciocutaneous (CFC) syndrome due to mutations in BRAF [70].