Inherited metabolic disorders among Turkish children withintellectual disability: A single-center experience

Abstract

Aim: We aimed to determine the frequency of inherited metabolic disorders (IMD) among Turkish children with intellectual disabilityusing laboratory tests for IMD. Materials and Methods: Children older than 5 years of age with intellectual disability admitted to the Pediatric Neurology OutpatientClinic for any neurological symptom between July 1, 2018, and December 31, 2018 were analyzed. Children with intellectual disabilityof unknown etiology at admission were included in the study. Complete blood count, serum biochemical analysis, thyroid functiontests, serum ammonia, lactate, homocysteine, biotinidase activity, serum amino acids, acylcarnitine profile, and urine organic acidanalysis results were evaluated. Results: A total of 163 patients (108 boys) were included in the study. The female to male ratio was 1: 2. The ages of the patientswere between 5 and 17 years and the mean age was 9.4 ± 3.6 years. Four patients were diagnosed with IMD. Two of them hadmitochondrial disease, 1 of them had isovaleric acidemia, and 1 of them had 3-Methylcrotonyl-CoA carboxylase deficiency. Theaccompanying symptoms of intellectual disability were psychiatric symptoms, dysarthria, ataxia, tremor and seizure in childrendiagnosed with IMD. We found that the percentage of IMD was 2.5% among Turkish children with intellectual disability. Conclusion: In our study, all IMDs identified in children with intellectual disability were treatable. That result emphasizes thesignificance of evaluating children for inherited metabolic disorders among children with intellectual disability.