S.N. | Basis | Autosomal Dominant | Autosomal Recessive | X-linked |
---|---|---|---|---|
1 | Mode of Inheritance | Only one copy of mutant allele is sufficient for expression | Two copies of mutant allele are required for expression | Mutation on X chromosome; typically expressed in males |
2 | Parental Transmission | Affected parent can transmit to offspring regardless of sex | Both parents must be carriers for offspring to be affected | Carrier mothers transmit to sons; daughters may be carriers |
3 | Risk to Offspring | 50% chance if one parent is affected | 25% chance if both parents are carriers | 50% chance for sons to be affected if mother is carrier |
4 | Carrier State | Not typically used; carriers usually express the trait | Carriers are asymptomatic | Females may be carriers; typically asymptomatic |
5 | Examples | 1. Marfan syndrome 2. Ehlers-Danlos syndrome | 3. Sickle cell anaemia 4. Thalassemias | 5. Muscular dystrophy 6. Haemophilia |
1.
[2066]
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2.
[2066]
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3.
[2067]
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4.
[2066 new]
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5.
(3)
[2072]
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6.
(3)
[2076]
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1.
[2059]
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2.
[2062]
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3.
[2074]
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1.
[2055]
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2.
[2076]
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1.
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2.
[2058]
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1.
[2055]
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