A Case of Maple Syrup Urine Disease detected by Tandem Mass Spectrometry in Newborn Screening Test

Maple syrup urine disease (MSUD) is an autosomal recessive disorder. Impaired activity of the branched-chain 2-oxo acid dehydrogenase complex causes accumulation of branched-chain L-amino and 2-oxo acid that can exert neurotoxic effects. MSUD presents heterogeneous clinical and molecular phenotypes. Severity of the disease, ranging from classical to mild variant types, is commonly classified on the basis of indirect parameters, e.g. onset, leucine tolerance and/or residual enzyme activity in cell. Since early 1990's, tandem mass spectrometry has been applied to newborn screening, because it is amenable to population-wide testing for a large number of disorders of fatty acid, organic acid, and amino acid metabolism. And so, we report a case of MSUD in 15 days old boy detected by newborn screening using tandem mass spectrometry.

Follow up of Infants with Congenital Hypothyroidism Who were Detected by Newborn Screening Test

PURPOSE: Developmental delay in congenital hypothyroidism can be prevented by early detection and treatment. We conducted a follow-up study to assess the growth and development of infants with congenital hypothyroidism who were detected by newborn screening test and received thyroid hormone therapy. METHODS: Nineteen hypothyroid infants were detected by newborn screening test from April 1995 to May 1997. Measurements of free T4 and TSH levels by radioimmunoassay were used as a screening test, and serum T4, T3, free T4, TSH, TBG levels were measured and radioisotope scan of thyroid gland were done for final diagnosis. Height and weight measurements, thyroid function test, and Bayley Scales of Infant Development(BSID II) were done during follow up. RESULTS: Male to female ratio was 2.2 : 1. The etiologies of congenital hypothyroidism were dyshormonogenesis(7 cases), hypoplasia(6 cases), ectopic gland(5 cases), and aplasia(1 case). All but one infant revealed normal physical growth. Mild developmental delay was detected in five cases by BSID-II about ten months after thyroxine replacement. Two cases revealed mild delay in Mental Developmental Index and 2 cases showed mild delay in Psychomotor Developmental Index, only one case was delayed in both indices. There was a negative correlation between PDI and age of starting treatment(r=-0.505, P<0.05), and a positive correlation between free T4 at the time of diagnosis and MDI(r=0.472, P<0.05). CONCLUSION: Early diagnosis and treatment were important for normal growth and development of hypothyroid infants, and Bayley developmental scale can be used for long term follow up.