BGEN 3020 Lecture Notes - Lecture 28: Trinucleotide Repeat Disorder, Fragile X Syndrome, Fmr1

• School: University of Manitoba
• Department: Biochem. and Medical Genetics
• Course: BGEN 3020
• Professor: Merz

Document Summary

Syndrome (many distinct symptoms) with intellectual impairment, characteristic physical features, autism, hyperactivity. Misleading doesn"t involve a fragile x chromosome: syndrome = affects more than one thing. Characteristics of fragile x syndrome for males: prominent or long ears, a long face, delayed speech, large testes (macroorchidism, hyperactivity, tactile defensiveness, gross motor delays, autistic-like behaviours. X-linked dominant but with variable expressivity and penetrance. Females less severe (50% penetrance: only 50% of the females born with it will have the phenotype, due to barr bodies. If they are born with it, then they will 100% have the phenotype. Anticipation occurs in females (from permutation to clinical) Males do not pass full mutation to daughters, only the permutation: cannot pass on the clinical due to defective sperm. Treatment is management of mood disorders, hyperactivity, etc. Cgg triplet repeat in the 5" utr of the fmr1 gene on the x chromosome: normal is 5-40 repeats, disease is over 200 repeats.