The Clinical Experience Of Childhood Cardiomyopathy Caused By Inborn Errors Of Metabolism In 12 Cases

The American Academy of Pediatrics cardiomyopathy registration data shows that metabolic disease accounted for 4%in more than 1,400 cases of newly diagnosed with dilated cardiomyopathy from 1990 to 2002.This kind of cardiomyopathy caused by the inborn errors of metabolism(IEM)also known as metabolic cardiomyopathy.The incidence of IEM in neonates is at least 1/2500,of which 5%combined with cardiomyopathy.More than 40 different IEM involving cardiomyopathy exist,including fatty acid oxidation defects,glycogen metabolism deficiency,mitochondrial disease,amino acid metabolism deficiency,organic acid metabolism deficiency and storage disease.Most IEM present in infancy or early childhood with signs and symptoms of multi-organ system dysfunction.Disease pathophysiology may include infiltration of cardiac myocytes with stored substrate,impaired energy production and production of toxic intermediary metabolites.Dietary modification,avoidance of fasting,and vitamin supplements are the mainstays of treatment for most”small molecule”diseases.Several lysosomal storage disorders are now treatable by enzyme replacement therapy or bone marrow transplantation.Newborn screening using tandem mass-spectrometry offers the potential for presymptomatic diagnosis,which will likely change their prevalence and natural history of cardiomyopathy.【Objective】To clarify and find the cause of cardiomyopathy in children and make sure the relationship between metabolic defects and cardiomyopathy.To research the clinical and echocardiography features and diagnostic criteria,efficacy of treatment and prognosis of metabolic cardiomyopathy.【Method】113 children diagnosed as cardiomyopathy in Shanghai Children’s Hospital during June 2012 to June 2015 were recruited.Their disease history,presenting symptom,physical signs,biochemical tests and examinations of electrocardiogram and echoeardiography were analyzed retrospectively.Follow-up data on motor development and survival were also collected and analyzed retrospectively.【Results】7 cases were diagnosed as infantile-onset GSDⅡ,in which the peripheral blood levels of acidic α-glucosidase were remarkably low or completely absent.All of them were complicated with cardiac hypertrophy.Severe muscular weakness,hypotonia and development lag were found in all during the follow-up.Creatine kinase was detected in all patients and its level became highly elevated.Alanine aminotransferase and aspartate aminotransferase were detected in 7 patients and their levels became significantly elevated in all of them.In 4 patients with primary carnitine deficiency,the left ventricular cavity was enlarged and the left ventricular systolic function was significantly decreased,after the therapy of L-carnitine,left ventricular ejection fraction(LVEF)returned to normal completely in all the 4 patients,left ventricular end-diastolic diamete(LVDd)decreased further in all the patients.Clinical improvement was dramatic.The main clinical manifestations of the 1 patient with Barth syndrome were cardiomyopathy and heart failure,also was diagnosed of left ventricular noncompaction(LVNC).The patient was presented with motor retardation,muscle weakness,growth delay and significantly increased urinary excretion of 3-methylglutaconic acid(3-MGC),and also was found to have neutropenia.【Conclusion】IEM is an important cause of children cardiomyopathy which varied in clinical manifestation,diagnosis,treatment and prognosis of different kinds of metabolic cardiomyopathy.Early diagnosis and treatment could be lifesaving for cardiomyopathy caused by IEM.