Question

An infant born prematurely to a 42-year-old Caucasian female in small for gestational age. Physical examination reveals microcephaly, low-set ears, prominent occiput and small mandible. The infant's fists are clenched and the fingers overlap. A bilateral fool deformity is observed. Which of the following is the most likely karyotype abnormality in this infant?

A. Trisomy 21
B. Trisomy 18
C. Trisomy 13
D. 47,XXX
E. 47,XXY

Answer 1

The infant with the described physical features likely has Trisomy 18 (Edwards Syndrome), which includes an extra chromosome 18 and presents with severe clinical symptoms.

Step-by-step explanation:

The physical characteristics described in the question - microcephaly, low-set ears, prominent occiput, small mandible, clenched fists with overlapping fingers, and bilateral foot deformity - are classic features of Trisomy 18, also known as Edwards Syndrome. This is a condition where there is an extra chromosome 18. Unlike Trisomy 21, which causes Down Syndrome, Trisomy 18 is typically associated with more severe clinical manifestations and a poorer prognosis. Therefore, the most likely karyotype abnormality in the infant described is B. Trisomy 18.