Genotype-phenotype correlation in a newborn with de novo 3p25 deletion syndrome

The 3p25 deletion syndrome is a very rare genetic abnormality, characterized by growth and psychomotor retardation, microcephaly, hypotonia, congenital heart defects, ptosis and micrognathia. Less than 60 cases have been published in the literature so far. However, a few patients with normal or mild phenotype have also been described. The majority of the cases are de novo mutations, with variable chromosomal breakpoints. We present the case of a newborn infant with 3p25 deletion syndrome, whose genetic analysis was done by karyotyping, fluorescent in situ hybridization and array comparative genomic hybridization. The latter method enabled us to define the precise breakpoint and the genes involved in the deletion, thus we could provide information for further clinical management. We identified 43 OMIM genes in the deleted region, which may have a causative effect on the pscychomotor and developmental delay and also on the intellectual disability. Exact cytogenomic characterisation of a rare genetic syndrome may allow to employ personalised treatment. Orv Hetil. 2022; 163(12): 478-483.