Question

Identify ‘a’, ‘b’, ‘c’,‘d’, ‘e’, and ‘f’ in the table given below

No.	Syndrome	Cause	Characteristics of affected individuals	Sex male/female/both
1.	Down’s	Trisomy of 21	‘a’ i)ii)	‘b’
2.	‘c’	XXY	Overall masculine development	‘d’
3.	Turner’s	45 with XO	‘e’ i)ii)	‘f’

Answer 1

Hint:These are the disease of chromosomal abnormalities. XXY is a disease which occurs due to having an extra X chromosome instead of having a normal XY chromosome. Individuals with Turner’s syndrome disease appear to be shorter than normal and, because of a loss of ovarian function, are generally unable to produce a child (infertile).

Complete answer:
First we should know about genetic diseases to answer this question. Any disease caused by an abnormality of an individual's genetic structure is a genetic disease. The genetic abnormality may differ from minuscule to major — from a single-base, isolated mutation in the DNA of a single gene to a gross chromosomal abnormality including the subtraction or addition of an entire chromosome or chromosome set. Four types of genetic disorder (inherited) are present and they are single gene inheritance, chromosome abnormalities, multifactorial inheritance, and mitochondrial inheritance.

No.	Syndrome	Cause	Characteristics of affected individuals	Sex male/female/both
1.	Down’s	Trisomy of 21	‘a’ i) Low muscle toneii) Small stature	‘b’ Both
2.	‘c’ Klinefelter's syndrome	XXY	Overall masculine development	‘d’ Male
3.	Turner’s	45 with XO	‘e’ i) Heart defectsii)Webbed neck	‘f’ Female

>The genetic disorder caused by the development of an extra copy of chromosome 21 is Down syndrome. It's often referred to as Trisomy 21. Low muscle tone, upward slanting eyes, small stature, flattened facial appearance and nose are among its features. The sex of the child is unaffected by it, as it is an autosomal disorder.
>Klinefelter syndrome is an inherited disease in which males have two or more X chromosomes. He's had genotype 44+XXY. The infected person’s characteristics include overall male growth, infertility, swollen breast tissue. In men, this disorder is observed.
>Turner's syndrome is an inherited condition in which the X chromosome is partially or fully absent in females. 44 + XO is the genotype. Swelling of the feet and hands, webbed neck, heart defects and skeletal abnormalities, are all symptoms of the person affected. This disorder occurs in females.

Note:Down syndrome, Klinefelter syndrome, and Turner’s syndrome are considered as chromosomal abnormalities because disease occurs due to chromosomal effects. Few individuals inherit maternal genetic defects, whereas other genetic diseases are caused by inherited alterations or mutations in a preexisting gene or set of genes. Genetic mutations may occur either spontaneously or because of any exposure to the environment.