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Permalink 12:05:46 pm by gowri, Categories: Botany, Cell Biology and Genetics

GENETIC DISORDERS
These are inborn diseases caused due to the defective genes. they are of two types
1.chromosomal disorders
2. Gene disorders.

chromosomal disorders: change in the structure or on the number of the chromosomes leads to series of abnormalities and are collectively called syndrome. These changes either affect autosomes or allosomes.

Autosomal genetic disorders:

Disorder

cause chromosomal compliment and number

Symptoms

Down’s syndrome

[Langdon Down-1866]

trisomy 21. Due to the presence one extra chromosome on the 21st chromosome

44AA+1+XY/XX

no.47

→ Short stature, large head,

small nose, flat nose.

→_Open mouth with tongue out.

→ Eyes slant upward with

Epicanthal fold.

→ Mental retardation.

Edward’s syndrome

Trisomy 18

44AA+1+XY/XX

no.47

→ Long but narrow skull

→ Small face, short digits, corneal opacity, deafnes, mental retardation

Patau’s syndrome

Trisomy 13

44AA+1+XY/XX

no.47

→ Cleft palate and lip, polydactyla, anomalies in dermal pattern.

Wolf Hirschorn syndrome

Deletion of short arm of the 4th chromosome

→ Microcephaly, wide set eyes.



Allosomal genetic disorders:

Disorder cause chromosomal compliment and number Symptoms

Turner’s syndrome

Dr.Henry Turner

Monosomy, Due to the absence of one X chromosome.

44AA+XO

No.45

→ Sterile female

→ Poorly developed secondary sexual characters.

→ short stature, webbed neck, broad shield like chest

→ Under developed ovaries.

→ Low IQ

→ Absence of menstrual cycle.

Nooman’s syndrome

Monosomy, due to the absence of Y chromosome.

44AA+YO

No.45

→ sterile males

→ Sterile males

→ Poorly developed secondary sexual characters and reproductive organs

Super Males

Trisomy, due to presence of one extra Y chromosome

44AA+XYY

No.47

→ tall, excess testosterone secretion, lowIQ.

Super Female

Trisomy, due to presence of one extra X chromosome

44AA+XXX/XXXX

No.47/48

→ Mental retardation

→ Low fertility

Klinefelter’s syndrome

Dr.Harry Klinefelter

Trisomy due to the presence of one extra X chromosome.

44AA+XXY/XXXY

No.47

→ Sterile males

→ Poorly developed secondary sexual characters and reproductive organs.

→ Development of breast (Gynacomastia).


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1 comment

Comment from: aihwarya [Visitor]
good synopsis..... very useful....
02/07/10 @ 20:42

This post has 3 feedbacks awaiting moderation...

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