Tetrasomy 9p, a Prenatal Challenge: Two Novel Cases

Katrien Janssens,Mahtab Zaghi,Wim Hectors,Philip Loquet,Bettina Blaumeiser

doi:10.3390/reprodmed3010005

Abstract

Tetrasomy 9p is a chromosomal disorder characterized by the presence of a supernumerary chromosome. This rare abnormality exhibits a broad phenotypic variability and is not clearly distinguishable from other more frequent aneuploidies in the prenatal setting. We present two prenatal cases with dissimilar phenotypes, one with solely increased fetal nuchal translucency and one with multiple congenital anomalies, and discuss prior studies. These cases illustrate the difficulty of prenatally diagnosing this condition based on phenotypic information alone. We conclude that invasive prenatal diagnosis with (molecular) karyotyping is the best choice for the prenatal detection of tetrasomy 9p.

Highlights

Tetrasomy 9p is a chromosomal disorder characterized by the presence of a supernumerary chromosome, isochromosome 9p, originating from the short arm of chromosome 9 [1]
We describe two prenatal cases with a molecularly proven tetrasomy 9p
In 2015 El Khattabi et al described the first case of possible parental germline mosaicism, reporting two siblings with tetrasomy 9p [1]

Summary

Introduction

Tetrasomy 9p is a chromosomal disorder characterized by the presence of a supernumerary chromosome, isochromosome 9p, originating from the short arm of chromosome 9 [1]. We present two prenatal cases of tetrasomy 9p, with different clinical manifestations, thereby contributing to the existing knowledge on this rare chromosomal aberration.

Results

Conclusion