Outcome of Inherited Metabolic Disorders Presenting in the Neonatal Period

To assess the outcome of infants who were diagnosed to have Inborn errors of metabolism (IEM) during neonatal period from a single center in South India.

This retrospective cohort study included consecutive neonates diagnosed to have IEM by biochemical testing or those detected using newborn screening (NBS) between November 2014 and July 2018. Disorders were categorized into intoxication and non-intoxication groups. Their presentation and outcome were described. Development at 12 mo was assessed objectively using DASII (Developmental assessment scale for Indian infants). Developmental quotient <70 was considered as delay. Mortality was analyzed using Kaplan Meier survival analysis.

Among the total of 33 (14 intoxication and 19 non-intoxication groups), 7 died in neonatal period, 3 were lost to follow-up, 9 expired during varying period leaving 14 under regular follow-up. NBS detected 3 of them, others presented symptomatically unwell during neonatal period. Median survival was 18 mo (95% CI 3.7 to 32.2). Kaplan Meier survival analysis revealed a significant difference in mortality in intoxication compared to non-intoxication group. Among 14 survivors, 7 (50%) had developmental delay; 5 (35%) had seizures; 6 (43%) had growth failure. Infants with encephalopathy as initial presentation had poorer prognosis. NBS detection rate was 1 in 1060 live births (3 positives out of 3180 NBS samples). Those detected by NBS remained well.

Morbidity and mortality remain high in those diagnosed as IEM during neonatal period. Despite the small sample size, this study calls attention to implement NBS wherever feasible.