Evaluation of total plasma homocysteine in Indian newborns using heel-prick samples.

OBJECTIVE: To estimate total plasma homocysteine levels in Indian newborns by modifying the existing SBD-F based High performance liquid chromotography (HPLC) method in order to enable analysis in newborn heel-prick samples and assess the prevalence of hyperhomocysteinemia in Indian newborns who are exclusively breast-fed. METHODS: Reverse-phase HPLC with fluorescence detection for plasma homocysteine estimation and statistical analysis using student t-test. RESULTS: SBD-F based HPLC method was modified and Bland and Altman analysis was carried out to assess agreement between original and modified methods. The correlation co-efficient was 0.994. The limits of agreement (-5.9, 6.3) were small enough to apply new method in place of the old for heel-prick sample analysis. Total plasma homocysteine analysis was carried out on heel-prick samples of 607 randomly selected newborns (331 males and 276 females). The mean plasma homocysteine estimated by this method in Indian newborns was 6.99 (95% CI: 6.48-7.49) with no appreciable gender effect (P=0.74). Elevated homocysteine levels were observed in 31 males and 21 females. CONCLUSIONS: Modified HPLC method is validated and can be used for homocysteine analysis on newborn heel-prick samples. Using this method, the prevalence of hyperhomocysteinemia in Indian newborns is 8.6%.

Newborn screening in India.

Expanded newborn screening (NBS) is aimed for early detection and intervention of treatable inborn errors of metabolism and also to establish incidence of these disorders in this part of the globe. The first expanded NBS programme initiated in the capital city of Andhra Pradesh to screen all the newborns born in four major Government Maternity Hospitals in Hyderabad by heel prick capillary blood collected on S&S 903 filter paper. Chromatographic (TLC and HPLC), electrophoretic (cellulose acetate and agarose) and ELISA based assays have been employed for screening of common inborn errors of metabolism. This study has shown a high prevalence of treatable Inborn errors of metabolism. Congenital hypothyroidsm is the most common disorder (1 in 1700) followed by congenital Adrenal Hyperplasia (1 in 2575) and Hyperhomocystenemia (1 in 100). Interestingly, a very high prevalence of inborn errors of metabolism to the extent of 1 in every thousand newborns was observed. The study reveals the importance of screening in India, necessitating nation wide large-scale screening.