Partial trisomy 9 with t(9;21)(q22; q10) translocation detected in prenatal diagnosis

Abstract

Trisomy 9p may occur due to either parental reciprocal translocation of chromosome 9 with other chromosomes or de-novo aberrations. Typical craniofacial features, intrauterine developmental delay, cleft lip-palate, micrognathia, cardiac abnormalities and congenital hip dislocation are findings which are expected to be seen in patients with partial trisomy 9pter->q22-32. With the triple testing of a 28-year-old G4P0A3 pregnant woman, performed during her fourth pregnancy, the risk of trisomy 18 was found to be increased. A cytogenetic analysis of the amniotic fluid was performed to establish prenatal diagnosis, and revealed the presence of three chromosome 9 and one chromosome 21. Thereupon, subsequent metaphase FISH analysis showed that one of three chromosome 9 was translocated with one of the chromosome 21 and this was considered to be partial trisomy 9 (pter->q22). As the parents have normal karyotype, this change in the fetus was considered to be de-novo. With the autopsy performed following the termination, the presence of agenesis of the corpus callosum and inlet VSD, which had been observed with previous the fetal USG was confirmed. This case will contribute to knowledge of the clinical evaluation of chromosomal abnormality including both 9p trisomy and chromosome 21 translocation, and also to genetic counseling for these patients.