Clinical characteristics of neonates with inborn errors of metabolism detected by Tandem MS analysis in Oman

We reviewed the clinical profile of our neonates diagnosed to have inborn errors of metabolism (IEM) by Tandem Mass Spectrometry (TMS) over a seven years period, and compared the results with published reports. We also attempted to evaluate various clinical situations wherein the screening test would yield a high pick up rate. Among the 166 neonates studied (10 aged 1 day, 79 aged 2-7 days and 77 aged 8-28 days), significant abnormalities on TMS suggestive of IEM were detected in 38 babies (23%), most common diseases diagnosed were maple syrup urine disease (10 neonates), propionic acidemia (8 neonates), urea cycle diseases (6 neonates) and isovaleric acidemia (4 neonates). The detection incidence was calculated to be one positive case out of every 4 to 5 babies tested. A high prevalence of parental consanguinity and high level of positive family history of affected siblings were the highlights of this study. The major clinical situations where testing was helpful were (a) unexplained acute neonatal encephalopathy, (b) positive family history of known or suspected IEM and (c) new born presenting with abnormal serum biochemistry suggestive of IEM.