Question

An abnormal human male phenotype involved an extra Y-chromosome(XYY) is a case of
A)Edward's syndrome
B)Jacob syndrome
C)Intersex
D)Down's syndrome

Answer 1

Its symptoms are increased height which usually becomes apparent after the age of five and results in an average height of about 6 feet, 3 inches by adulthood. Some of the individuals with XYY can also develop severe cystic acne during adolescence.

Complete answer:
Option A is incorrect as Edwards syndrome is a chromosomal abnormality which is characterized by the presence of an extra copy of a gene on the 18th chromosome.
Option B is correct as Jacob syndrome is a rare chromosomal disorder which affects males only. It is caused by the presence of an extra copy of the Y chromosome. Males normally have one X and one Y chromosome. But the individuals with this syndrome have one X and two Y chromosomes.
Option C is incorrect as Intersex is a term used for kinds of conditions in which a person is born with a reproductive or sexual anatomy that doesn't seem to fit in a typical definitions of female or male.
Option D is incorrect as Down's syndrome, also known as trisomy 21, is a genetic disorder which is caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays and mild to moderate intellectual disability.

Hence, the correct answer is option (B)

Note: The signs and symptoms of 47, XYY syndrome can be managed with a variety of therapies. Occupational therapy may be recommended for infants and young boys who have low muscle tone and speech therapy may be recommended for boys who have speech delay.