Fragile X Syndrome PDF
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Uploaded by SelfSatisfactionRetinalite2084
G. H. Raisoni
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Summary
This document explains the fragile X-associated mental retardation syndrome, covering various aspects like the premutation allele, genetic mosaicism, and methylation patterns. It also describes the percentage of carrier males who may not exhibit any symptoms.
Full Transcript
Explanation: A premutation allele, when transmitted by a female, has a likelihood to expand into a full mutation, especially as the size of the repeat segment increases. 2. (C): Fragile X-associated mental retardation syndrome Explanation: Fragile X-associated mental retardation syndrome occurs due...
Explanation: A premutation allele, when transmitted by a female, has a likelihood to expand into a full mutation, especially as the size of the repeat segment increases. 2. (C): Fragile X-associated mental retardation syndrome Explanation: Fragile X-associated mental retardation syndrome occurs due to the amplification of the (5?-CGG-3?)n repeat segments, leading to a deficiency in the FMR1 protein. 3. (B): It can contribute to varying phenotypes among cells. Explanation: Genetic mosaicism refers to the presence of varying numbers of DNA repeats in different cells, which can result in different phenotypes in an individual. 4. (B): Unmethylated in male cells Explanation: The CpG island at Xq27.3 is typically unmethylated in male cells but can be methylated in one of two X chromosomes in female cells, especially in affected individuals. 5. (B): 20% Explanation: Approximately 20% of carrier males for fragile X syndrome do not exhibit any signs of the syndrome despite carrying the mutation.
