Tetrasomy 9p syndrome in a Filipino infant

@#Tetrasomy 9p syndrome is a rare chromosomal abnormality syndrome whose most common features include hypertelorism, malformed ears, bulbous nose and microretrognathia. These features present as a result of an additional two copies of the short arm of chromosome 9. Here we present a neonate with characteristic facial features of hypertelorism, downslanted palpebral fissure, bulbous nose, small cupped ears, cleft lip and palate, and downturned corners of the mouth. Clinical features were consistent with the cytogenetic analysis of tetrasomy 9p. In general, clinicians are not as familiar with the features of tetrasomy 9p syndrome as that of more common chromosomal abnormalities like trisomies 13, 18, and 21. Hence, this case re-emphasizes the importance of doing the standard karyotyping for patients presenting with multiple congenital anomalies. Also, this is the first reported case of Tetrasomy 9p syndrome in Filipinos.

A Case of Tetrasomy 9P

Supernumerary isochromosome resulting in autosomal tetrasomy are rare and have been described only for 12P, 18P, and 9P. Tetrasomy 9P, initially described by Ghymer et al, is a rare chromosomal aberration that has been described in 20 patients. Affected subjects show both cytogenetic and ohenotypic variability. Some patients have the abnormal cell line in all cells, but many display tissue limited mosaicism. The phenotype varies in severity from prenatal death to mild developmental delay and minor anomalies. We reported a infant with mild manifestations of tetrasomy 9p with brief review of related literatures.