Genetic Disorder in Man

Genetic Disorder in Man

Genetic Disorder in Man  –   In human sex chromosomes, the male have the genotype xy and female have the genotype xx. Owing to an error in cell dinsion, the Y chromosi=ome is lost from an ordinary (xy) male producing XO, and added to female which therefore becomes xxy. It will be realized that this must have a severe effect in the human situation, but not where sex depends upon the number of X- chromosomes. Therefore the genetic disorder in man include the following:-

Klinefelter’s Syndrome: The xxy individuals are women largely converted to men and passing as such. This conditions called klinefelter’s syndrome and the affected individual is called klinefelter’s. klinefelter’s syndrome therefore is a genetic disorder in human male caused by the presence of an extra X chromosome. Klinefelter males are xxy instead of xy. They can be identified because, though the passes male genital organs, they are some what immature and feminine in types. The file is smooth, the voice high and the breast enlarged. Such people are liable to metal deficiency, though some are fairly and a few are quite, intelligent. Such people may not produce children and can be weeded out of the population by natural selection

Tumer’s syndrome:- A genetic condition in human females caused by a 45, x genotype (OX) such individuals are phenotypically females, but are sterile because of undeveloped ovaries. Such people are stunted, immature girls who midly ever mensurate and they frequently suffer from a major abnormality of the aorta.

Down Syndrom: Another combination, xxy, also occurs in about 1 in 1000 male births. The xxy males are usually fertile and their meiosis are of xy type. The extra Y is not transmitted and their gametes contain either X or Y, never YY or XY. The most common type of down syndrome is trisomy 21 caused by non-disjunction of chromosome 21 in a parent that is chromosomally normal. There is maternal age effect for down’s syndrome. Older mothers show greatly elevated risk of having down syndrome children.

The abnormalities of down’s syndrome include mental retardation with an 10 to the 20 to 50 range, broad flate face, eye with an epicanthic fold, short stature, short hands with a crease across the middle, and a large wrinkled tongue. Females may be fertile, and may produce normal or trisomic progeny, but males have never reproduced. Mean life expectancy as about 17 years, and only 8 percent suwice past age 40.

Sickle Cell Disease – Sickle cell disease as a gentical disorder caused by a point mutation in DNA. It as caused due to the presence in red blood cells of an abnormal form of haemoglobin, S CHbs ) instead of hemoglobin A (HbA). There are many various of haemoglobin and each as made up of two chains of globin containing amino acid known as x and β –globin chains. The difference between haemoglobin A and haemoglobin S is the presence of amino acid, valine in position 6 of the β – chain

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