Which of the following is the most likely inheritance pattern in the pedigree given below-
Correct Answer: X-linked dominant
Description: It is an X-linked dominant pattern of inheritance.
The features which suggest the X-linked dominant pattern of inheritance are-
A single abnormal X chromosome is sufficient to express the disease.
All of the female offspring’s of a diseased male XY will receive the abnormal X chromosome and express the disease, whereas none of the male offspring to the diseased father will have the disease (as sons don't receive X chromosome from their father).
A diseased mother can transmit the abnormal X chromosome to both daughter and sons equally.
Important facts
If a female is transmitting the disease to all offspring’s (both males and females) and a male is not transmitting the disease to any child, it is mitochondrial inheritance.
If a male is transmitting the disease only to daughters (all daughters) and not to the sons whereas female transmit the disease to half daughters and half of the sons, it is X-linked dominant.
If only males are affected in a pedigree, it is likely to be an X-linked recessive disease (females act as carriers; only transmit the disease and themselves remain unaffected).
If there is no sex-predilection and affected individuals transmit the disease to half of the offspring’s, it is an autosomal dominant disorder.
If there is no sex-predilection and affected individuals transmit the disease to one-fourth of the offspring’s, it is likely to be an autosomal recessive disorder.
Category:
Pathology
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