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Important findings in Fragile X syndrome= "6M"

1) Mental Retardation

2) Mutation in FMR1 gene on X chromosome (X linked Dominant)

3) Macro jaw(large jaw)

4) Macro orchidism

5) Macrotia (large everted ears)

6) Mitral valve prolapse is associated with it.

(Other points to remember for Fragile X=1)CGG Trinucleotide repeats in non coding region of DNA 2)can cause Attention deficit disorder in females):)
 

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It's debatable whether it is dominant or recessive - different texts say different things. The variable penetrance that results from both the anticipation of the trinucleotide repeat and the mosaicism of X inactivation makes it confusing. The way we classically think of an x-linked recessive disease, the mutation is phenotypically silent in females. This is not true of Fragile X, so many sources list it as an x-linked dominant. However, with a smaller number of repeats, the mother can have a normal phenotype (so an affected son could inherit from an unaffected mother), so other sources list it as x-linked recessive. Hopefully, given the differing versions, there won't be a question on the exam directly asking whether FXS is recessive or dominant!
:eek:
 
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