Adult recurrence of cardiomyopathy due to poor compliance in a female diagnosed in infancy with carnitine transporter defect

Abstract

Carnitine transporter defect (CTD), also known as carnitine uptake defect, is an autosomal recessive disorder caused by mutations in the SLC22A5 gene encoding the plasma membrane carnitine transporter OCTN2. CTD causes carnitine depletion, but the clinical spectrum is broad, encompassing metabolic crises in infancy, childhood cardiomyopathy, fatigability in adulthood and complete absence of symptoms. We report on a 24 year old female who was diagnosed with CTD and commenced on carnitine therapy when she developed cardiomyopathy at 9 months of age. Her older brother had succumbed to cardiomyopathy at around 18 months of age and was unfortunately diagnosed too late for treatment to be instituted. Our patient's cardiomyopathy resolved within 6 weeks on carnitine treatment and did not recur in childhood despite periods of up to 3 months of minimal carnitine, including 2 weeks without therapy. She had a normal echocardiogram at the age of 24, however ceased carnitine due to a lack of a script after moving interstate and she presented with gastroenteritis 3 months later. An echocardiogram showed severe biventricular dilatation, global hypokinesis and moderately impaired function, with a left ventricular ejection fraction of 40%. One month later, significant interval improvement was noted. The left ventricle remained severely dilated, but with an improved ejection fraction of 51% (low normal systolic function). Carnitine supplementation has dramatically altered the natural history of cardiomyopathy in CTD, achieving long-term cardiac stability. Follow up echocardiography is needed to determine whether the reinstitution of therapy will result in complete resolution of our patient's cardiomyopathy.L6124788852016-10-07 <br />