Triploidy/Diploidy Mosaisizm, Diandry and Uniparental Isodisomy: Fetus with Omphalocele and Contracted Finger

Abstract

Omphalocele is an abdominal wall defect that bowel and/or other visceral organs herniate from umbical ring, which is covered by peritoneal sac. Omphalocele pathogenesis is not clear but familial and genetical factors plays important role to development of omphalocele. Twenty years old, 19 weeks 4 days pregnant, primigravid patient presented. In her ultrasonographic assessment omphalocele was detected and fetus was death. Pregnancy was terminated and genetic studies were performed from fetal blood and tissue biopsy. Karyotype from intracardiac blood sample was found 46, XX. QF-PCR analysis performed from the DNA obtained from fetal skin biopsy; 4:1 peak ratio observed in all the STR regions. This is the first case shows 4:1 peaks at QF-PCR. This finding was incompatible with karyotype. So mosaicism doubt occurred. FISH from skin biopsy showed diploid/triploid mosaicism. Fetuses with omphalocele must be evaluated for additional anomalies and genetic consultation. Our case indicates high frequency of mosaicism and the importance of examination from different tissues with different types of genetic methods. Triploid cell line is found only in fibroblasts in about 70% of cases, so this mixoploidy syndrome is likely underdiagnosed. Performing genetic analysis from different tissues and using different techniques are very important for detecting mosaicism and not to miss the genetic etiology of stillbirths and anomalous fetuses.