Prenatal diagnosis of a fetus with terminal deletion of chromosome 1 (q43) in first-trimester screening: is there a characteristic antenatal 1q deletion phenotype? A case report and review of the literature.

The terminal deletion of chromosome 1q is a disease of rare incidence. It might be hereditary or caused by spontaneous changes within the chromosome. Phenotypic characteristics including typical facial appearance, microcephaly, psychomotor retardation and variable other anomalies are suggested to be based on the loss of macrochromosomal materials within the long arm of chromosome 1. The number of symptoms is related to the loss of genetic material. To date, only very few cases of terminal 1q deletion syndrome have been diagnosed in utero, mainly after 20 weeks of gestation. Here, we present a case of del(1q)syndrome in a first-trimester fetus. Besides other structural anomalies of the fetus, prenatal ultrasound at 13 weeks' gestation demonstrated severe microgenia and suspicion of cardiac defect. Chorionic villous sampling was performed, and cytogenetic analysis showed a de novo terminal chromosome 1 long arm deletion. We discuss the structural features of antenatally diagnosed fetuses with terminal deletion of chromosome 1 and try to give an answer to the question whether there is a characteristic antenatal 1q deletion phenotype.