-Husna, Amity University Kolkata
Trisomy 14 is an aneusomy that is viable with life if present in a mosaic individual. Mostly, the symptoms are prenatal and postnatal growth failure, genitourinary and ear abnormalities, congenital heart defects, developmental delay, narrow palpebral fissures, broad nose, short jaw, and short neck. A clinical survey on 51 patients showed varying symptoms, depending on the degree of mosaicism, size of the trisomic segment, concurrence with other chromosomal imbalances, and the parental origin of the rearrangement due to the possible imprinting effects.
However, the case of a 1-year-old patient was referred to due to growth retardation, hypotonia, pigmentary mosaicism with phylloid hyperpigmentation along the body, and ambiguous genitalia. The child was born by vaginal delivery at 38.6 weeks from non-consanguineous parents. Unilateral left palpebral ptosis, broad nose and forehead, and hypochromic cutaneous spots on the neck were the symptoms after examining it physically and the neonatal screening was positive for congenital adrenal hyperplasia so immediately adequate medication was started
This case showed two rare cytogenetic events: an almost complete trisomy of chromosome 14, due to a Y-autosome translocation, and a mosaic for Turner syndrome. The expected mechanism behind 45, X/46, X, der(Y)t(Y;14) (p11.32; q12) fertilized egg with a subsequent loss of additional derivative chromosome 14, is due to fertilization of the normal oocyte by spermatozoid produced by adjacent segregation of an abnormal germline.
The use of a more advanced cytogenetic molecular technique like array comparative genomic hybridization is necessary to determine the precise gene content of the trisomic region and the specific location of the chromosome breakage; however, this technology wasn’t available. The prognosis for the patient is similar to individuals with Turner syndrome rather than a trisomy 14 mosaicism.
Hence, as the patient is still very young a clinical follow-up is necessary for improving phenotypic delineation and decide on any surgical decisions regarding the internal gonads.
Source: A toddler with phylloid-type pigmentary mosaicism and ambiguous genitalia resulting from trisomy 14 induced by a der(Y)t(Y;14) V. I. Romero, J. C. Pozo, S. Saenz, A. Llamos-Paneque, T. Liehr, K. Hosomichi & A. Tajima Human Genome Variation volume 7, Article number: 28 (2020)
https://www.nature.com/articles/s41439-020-00113-x
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