Question

The person with Turner’s syndrome has
A. 45 autosomes and X sex chromosomes
B. 44 autosomes and XYY sex chromosomes
C. 45 autosomes and XYY sex chromosomes
D. 44 autosomes and X sex chromosomes

Answer 1

Hint:- Turner’s syndrome is a genetic disorder found to affect only females. It was reported by Dr. Henry Turner in 1938. It is not an inherited genetic disorder but occurs during the formation of reproductive cells in a parent or during early cell division in embryo development. It causes a number of developmental problems.

Complete step-by-step solution:- Turner’s syndrome is usually diagnosed during infancy or early childhood. It affects the normal development of females before and after the birth. The most common symptom of Turner’s syndrome is short stature and sterility. This becomes evident in girls by the age of 5. At puberty, they do not experience the usual growth spurt and gonadal dysgenesis results in premature ovarian failure during early childhood. Thus, the ovaries do not produce estrogen and progesterone, the female sex hormones for the onset of puberty and the females remain sterile. Short web-like neck, low-set ears, a low hairline at the back of the head, and broad chest with widely spaced nipples are few other symptoms of the syndrome. Babies at birth may show smaller than average height at birth and swelling of hands and feet. About 5-10% of females may have a congenital heart disease which may later progress to congestive heart failure.
Turner’s syndrome is characterized by complete or partial absence of one of the two sex chromosome. It is also called as 45,X syndrome and is denoted by 44 +XO. It is caused due to nondisjunction of a pair of sex chromosome during the formation of a sperm or an egg in a parent. For example, when a sperm without an X chromosome unites with a normal egg to form an embryo, the embryo will have just one X chromosome instead of XX. Thus, the embryo cells will divide and each cell will be devoid of the missing X chromosome.
So the correct answer is (D), 44 autosomes and X sex chromosomes.

Note:-
Turner’s syndrome may occur due to one of the following genetic alterations.
- X-chromosome Monosomy (All cells have only X chromosomes)
- X-chromosome Mosaicism (Few cells have XX while few have only X chromosomes)
- X-chromosome defects
It has been observed that 50% of individuals having Turner’s syndrome have X-chromosome monosomy. Turner’s syndrome occurs in 1 among 2000 female births.