[Hypermethioninemia in the preterm newborn. Predisposing factors]

Abstract

Introduction: Excess methionine can cause central nervous system disorders such as diffuse cerebral edema and disorders of myelin.

Patients and method: A retrospective and prospective (ambispective) observational study in preterm newborns admitted to our hospital over a period of 15 months and who had hypermethioninemia in neonatal screening tests by tandem mass spectrometry. The progress of these infants was monitored during the first year of life, assessing their methionine levels, diet, somatometric parameters and neurodevelopment.

Results: From a study population of 187 preterm infants, 16 of them showed isolated hypermethioninemia. Weight and feeding the babies with a special formula enriched with methionine is related to an increased number of cases of transient isolated hypermethioninemia (62.6% received a higher contribution of methionine than 97mg/kg/day). We also found a statistically significant correlation between the days that patients received the formula and the time it takes to normalize the levels of methionine in plasma (R 0.791, p=0.000). There was no correlation between the methionine peak reached in plasma and the score on the Brunet Lézine test, at the corrected age of 6 months.

Conclusions: This study highlights the importance amino acid supplements, particularly methionine, in premature infants' formulas due to the impact they may have on neurological development.