Clinical analysis and long-term follow-up of multiple carboxylase deficiency in 15 children / 中华实用儿科临床杂志

ABSTRACT

Objective Multiple carboxylase deficiency(MCD) is an autosomal recessively inherited defect of organic acid metabolism.The underlying mechanism is biotinidase(BT) or holocarboxylase synthetase(HLCS) deficiency.The authors reported 15 cases of MCD(clinical characteristics,diagnosis and treatment) and outcomes of long-term follow-up.Methods The clinical data of 15 patients with MCD admitted to Guangzhou Women and Children's Medical Center between Aug.2001 and Feb.2013 were analyzed.The diagnosis was confirmed by urinary organic acid analysis with gas chromatography/mass spectrometry (GC/MS),blood enzymatic determination and gene analysis.The patients consisted of 12 male and 3 female.The onset age ranged from newborn infants to 16 months.Results 1.Remarkable elevations of urinary lactate,3-oxy-butyric acid,3-OH-isovalerate,methylcitrate,3-methylcrontonylglycine,3-OH-propionate were detected in all of 15 cases.Fourteen cases with HLCS deficiency and 1 case with BT deficiency were confirmed by gene analysis.2.Most of patients with HLCS deficiency presented in the neonatal period or early infancy.The main clinical manifestations were skin rash (14 cases),tachypnea (9 cases),developmental retardation (8 cases),vomiting(5 cases),poor feeding (3 cases),developmental regradation (1 case),convulsion (1 case).Laboratory evaluation showed persistent metabolic acidosis and varied degree of ketosis,lactic acidosis,hyperuricacidemia,ammoniemia and hypoglycemia.Biotin was given to 13 patients in 10 mg/d and their metabolic disorders were corrected within 48 h,except one who gave up treatment and died.Treatment with Biotin in 5 mg/d provided clinical stability and normal neurodevelopmental outcome on follow-up for 3-11 (6.47 ± 2.70) years.3.One patient with BT deficiency presented with severe neurological symptoms(impaired consciousness,limbs trembling,tachypnea with irregular respiratory rhythm) at 16 months old.Demyelination of corpus callosum was evident on magnetic resonance imaging.Biotin treatment was given to him on the second of onset,and 1-year follow-up indicated significant improvement of his clinical symptoms,but the right limb weakness did not completely recover.Conclusions The main clinical features of HLCS deficiency include frequent skin rash,tachypnea,and metabolic disorders.BT deficiency may produce variable neurologic manifestations including demyelination of corpus callosum.Urinary organic acid analysis with GC/MS is critical to the early diagnosis of MCD.Prompt biotin treatment is recommended to correct metabolic derangements and continued therapy is essential to the improvement of long-term prognosis.Delayed commencement of therapy in BT deficiency can result in irreversible neurological damage.