FMR1 is the only in which mutation is known to cause Fragile X, FXTAS and POI. FMR1 alleles are categorized according to the number of CGG trinucleotide repeats in 1 and the status of the repeat region. Both males and females with a are at increased risk for FXTAS. The prevalence of FXTAS is estimated at approximately 40% to 45% overall for males with premutations who are older than age 50 years. Penetrance in males is age related. FXTAS occurs in both males and female premutation carriers, but the in individuals older than age 50 years is lower in females (16.5%) than in males (45.5%) -How will the results of the genetic test, whether negative or positive, affect the future management of the member being tested? (Explain all that apply): Genotype-phenotype correlations exist (see table below). This Inform on prognosis information is useful in counseling families on what to expect clinically.2 Types of FMR1 Repeat Expansion Mutations Number of CGG Clinical Status Mutation Methylation Status Trinucleotide Type of FMR1 Male Female Repeats At risk for Premutation ~55-200 Unmethylated At risk for FXTAS POI and FXTAS ~50% with Completely ID, ~50% Full >200 100% with MR methylated normal intellect Partial: Varies between unmethylated in the premutation and Repeat size premutation cell line; full in different Nearly 100% with ID; methylated in the cell lines may be higher full- cell line Highly functioning than Partial: mixture of variable: males with full methylated and ranges from Methylation >200 unmethylated cell normal lines intellect to Nearly all have ID but often have Unmethylated >200 Unmethylated MR to full intellect ID=intellectual disability
FMR1 is the only in which mutation is known to cause Fragile X, FXTAS and POI. FMR1 alleles are categorized according to the number of CGG trinucleotide repeats in 1 and the status of the repeat region. Both males and females with a are at increased risk for FXTAS. The prevalence of FXTAS is estimated at approximately 40% to 45% overall for males with premutations who are older than age 50 years. Penetrance in males is age related. FXTAS occurs in both males and female premutation carriers, but the in individuals older than age 50 years is lower in females (16.5%) than in males (45.5%) -How will the results of the genetic test, whether negative or positive, affect the future management of the member being tested? (Explain all that apply): Inform on prognosis Genotype-phenotype correlations exist (see table below). This information is useful in counseling families on what to expect clinically.2 Types of FMR1 Repeat Expansion Mutations Mutation Type Number of CGG Trinucleotide Repeats Methylation Status of FMR1 Clinical Status Male Female Premutation ~55-200 Unmethylated At risk for FXTAS At risk for POI and FXTAS Full >200 Completely methylated 100% with MR ~50% with ID, ~50% normal intellect Repeat size Varies between premutation and full in different cell lines Partial: unmethylated in the premutation cell line; methylated in the full- cell line Nearly 100% with ID; may be higher functioning than males with full Highly variable: ranges from normal intellect to Methylation >200 Partial: mixture of methylated and unmethylated cell lines Unmethylated full >200 Unmethylated Nearly all have ID but often have MR to intellect ID=intellectual disability
FragileXParentalTest-.docx