Test Bank for Genetics Analysis and Principles WITH 100% ERIFIED QUESTIONS AND ANSWERS Osteogenesis imperfecta type I is the mildest form of osteogenesis imperfecta because most of the mutations that cause oste ogenesis imperfecta type I: - Result in no protein being produced from one allele (null allele) Duchenne and Becker muscular dystrophies result from mutations in the gene for dystrophin. The diseases differ in onset and severity, but not in inheritance pa ttern. They should therefore be considered: - Allelic diseases -- this is allelic heterogeneity Two maternal uncles with a clinical picture similar to the affected male child shows ______ inheritance - X-Linked recessive Advanced paternal age increases ri sk of which mutations? - New autosomal dominant mutations Advanced maternal age increases risk of? - Chromosomal aneuploidy Recurrent early pregnancy losses are often due to? - Chromosomal rearrangement Consanguinity increase the risk of? - Autosomal re cessive inheritance What term refers to the Classic forms of single -gene inheritance - Mendelian What term refers to the Inheritance pattern of a gene on an X or Y chromosome - Sex-
Linked What term refers to inactivation of a gene or genes dependent upo n the gender of the transmitting parent - Imprinting What is inheritance of extra -nuclear genetic material called? - Mitochondrial inheritance In which kind of inheritance are parents obligate carriers? - Autosomal recessive inheritance What is having only one allele at a locus referred to as? - Hemizygous A specific combination of linked alleles is called? - Haplotype Which ethnic group most often gets alpha -thalassemia? - Asians Which ethnic group most often gets beta -thalassemia? - Mediterraneans Which ethnic group most often gets Gaucher's disease? - Ashkenazic Jews Which ethnic group most often gets PKU? - Caucasians A patient has Duchenne Muscular Dystrophy (DMD) because exons 38 -44 and the intervening intronic DNA are missing. What kind of mutation is this? - Large deletion Tay-Sachs disease (hexosaminidase A deficiency) in 18% of Ashkenazi Jews and <1% of non -Ashkenazi is due to a G ->C at exon 12 resulting in inclusion of intron 12 in the mRNA. What kind of mutation is this? - RNA splicing mutation A patient has Duchenne Muscular Dystrophy (DMD) because he has two copies of exons 41 -45. What kind of mutation is this? - Large duplication Most patients in the United States have cystic fibrosis (CF) because of the deletion of 3 base pairs resulting in the loss of a phenylalanine at codon #508. What kind of mutation is this? - In-frame deletion The most common mechanism by which complete Trisomy 21 arises: - Maternal meiotic nondisjunction What gives most accurate info on fetal aneuploidy @ 12 weeks w/out placing pregnancy at risk? - Non-invastive prenatal testing (e.g. blood test) If a patient has a chromosomal translocation involving homologous chromosomes, e.g. 21;21 translocation, what is risk of having offspring with unbalanced chroms? - 100% Which chromosomal aneuploidy does NOT correlate with advanc ing age? - Turner Syndrome (45,x) What is Trisomy 13 called? - Patau syndrome What is Trisomy 18 called? - Edwards Syndrome A dominant pattern is typically exhibited when the normal gene product: - Functions as a structural protein The quickest and mos t accurate laboratory testing presently available to distinguish between trisomic and translocation forms of Down syndrome or Patau syndrome is: - Chromosomal (karyotype) analysis What is earliest and most accurate test for FXS? - Chorionic villus samplin g (9-14 wks)
Linked What term refers to inactivation of a gene or genes dependent upo n the gender of the transmitting parent - Imprinting What is inheritance of extra -nuclear genetic material called? - Mitochondrial inheritance In which kind of inheritance are parents obligate carriers? - Autosomal recessive inheritance What is having only one allele at a locus referred to as? - Hemizygous A specific combination of linked alleles is called? - Haplotype Which ethnic group most often gets alpha -thalassemia? - Asians Which ethnic group most often gets beta -thalassemia? - Mediterraneans Which ethnic group most often gets Gaucher's disease? - Ashkenazic Jews Which ethnic group most often gets PKU? - Caucasians A patient has Duchenne Muscular Dystrophy (DMD) because exons 38 -44 and the intervening intronic DNA are missing. What kind of mutation is this? - Large deletion Tay-Sachs disease (hexosaminidase A deficiency) in 18% of Ashkenazi Jews and <1% of non -Ashkenazi is due to a G ->C at exon 12 resulting in inclusion of intron 12 in the mRNA. What kind of mutation is this? - RNA splicing mutation A patient has Duchenne Muscular Dystrophy (DMD) because he has two copies of exons 41 -45. What kind of mutation is this? - Large duplication Most patients in the United States have cystic fibrosis (CF) because of the deletion of 3 base pairs resulting in the loss of a phenylalanine at codon #508. What kind of mutation is this? - In-frame deletion The most common mechanism by which complete Trisomy 21 arises: - Maternal meiotic nondisjunction What gives most accurate info on fetal aneuploidy @ 12 weeks w/out placing pregnancy at risk? - Non-invastive prenatal testing (e.g. blood test) If a patient has a chromosomal translocation involving homologous chromosomes, e.g. 21;21 translocation, what is risk of having offspring with unbalanced chroms? - 100% Which chromosomal aneuploidy does NOT correlate with advanc ing age? - Turner Syndrome (45,x) What is Trisomy 13 called? - Patau syndrome What is Trisomy 18 called? - Edwards Syndrome A dominant pattern is typically exhibited when the normal gene product: - Functions as a structural protein The quickest and mos t accurate laboratory testing presently available to distinguish between trisomic and translocation forms of Down syndrome or Patau syndrome is: - Chromosomal (karyotype) analysis What is earliest and most accurate test for FXS? - Chorionic villus samplin g (9-14 wks)
