Neonatal hypoglycemia is generally observed in MODY 1 infants, but it is possible to hypothesize that some HNF-1α mutations could lead to a functionally impaired protein that might dysregulate HNF-4α expression determining hypoglycemia.
Both families displayed phenotypes typical of HNF4A monogenic beta-cell diabetes, including at least two affected generations, good response to sulphonylurea treatment and increased birthweight and/or neonatal hypoglycaemia.
The phenotype associated with heterozygous HNF4A gene mutations has recently been extended to include diazoxide responsive neonatal hypoglycemia in addition to maturity-onset diabetes of the young (MODY).