Modern advances in medicine make it possible to maintain a high standard of living for patients with phenylketonuria (PKU). At the same time, numerous measures for the prevention and treatment of PKU reduce the number of cases of irreversible changes in the body of patients. However, the question of the influence of social factors that can cause the birth of children in PKU-sick mothers with congenital malformations remains relevant. The article presents a clinical case of microcephaly in two children as a result of maternal PKU. An analysis of the materials of the medical records of children in the children’s home, the results of clinical, laboratory, and instrumental examination methods was carried out. This clinical case confirms the high probability of giving birth to children with microcephaly in the absence of metabolic control in mothers with PKU. At the same time, the mother’s antisocial lifestyle and socio-economic factors caused the birth of a second child with the same pathology.

Keywords: hereditary metabolic diseases, embryopathies, microcephaly, maternal phenylketonuria syndrome, phenylketonuria