# Analysis of alcohol-metabolizing enzymes genetic variants and RAR/RXR expression in patients diagnosed with fetal alcohol syndrome: a case-control study

## TL;DR

This study explores how genetic differences in alcohol-metabolizing enzymes and retinoic acid pathway genes may influence the development of fetal alcohol syndrome.

## Contribution

The study identifies specific genetic variants in alcohol-metabolizing enzymes and retinoic acid pathway dysregulation in children with fetal alcohol syndrome.

## Key findings

- Children without fetal alcohol spectrum disorder had higher frequencies of ADH1B*3 and ADH1C*1 alleles, which increase alcohol metabolism.
- FAS children had an ADH4 variant with weak teratogen binding, leading to higher fetal alcohol exposure.
- Both groups showed dysregulated expression of retinoic acid pathway genes like RAR and RXR.

## Abstract

Understanding the mechanisms underlying alcohol metabolism and its regulation, including the effect of polymorphisms in alcohol-metabolizing enzymes, is crucial for research on Fetal Alcohol Spectrum Disorders. The aim of this study was to identify specific single nucleotide polymorphisms in key alcohol-metabolizing enzymes in a cohort of 71 children, including children with fetal alcohol syndrome, children prenatally exposed to ethanol but without fetal alcohol spectrum disorder, and controls. We hypothesized that certain genetic variants related to alcohol metabolism may be fixed in these populations, giving them a particular alcohol metabolism profile. In addition, the difference in certain isoforms of these enzymes determines their affinity for alcohol, which also affects the metabolism of retinoic acid, which is key to the proper development of the central nervous system. Our results showed that children prenatally exposed to ethanol without fetal alcohol spectrum disorder traits had a higher frequency of the ADH1B*3 and ADH1C*1 alleles, which are associated with increased alcohol metabolism and therefore a protective factor against circulating alcohol in the fetus after maternal drinking, compared to FAS children who had an allele with a lower affinity for alcohol. This study also revealed the presence of an ADH4 variant in the FAS population that binds weakly to the teratogen, allowing increased circulation of the toxic agent and direct induction of developmental abnormalities in the fetus. However, both groups showed dysregulation in the expression of genes related to the retinoic acid pathway, such as retinoic acid receptor and retinoid X receptor, which are involved in the development, regeneration, and maintenance of the nervous system. These findings highlight the importance of understanding the interplay between alcohol metabolism, the retinoic acid pathway and genetic factors in the development of fetal alcohol syndrome.

The online version contains supplementary material available at 10.1186/s12864-024-10516-7.