03-11-2008, 11:35 AM
A family in which several individuals have arthritis and detached retina is diagnosed with Stickler syndrome. The locus for Stickler syndrome has been mapped near that for type II collagen on chromosome 12, and mutations in the COL2A1 gene have been described in Stickler syndrome. The family became interested in molecular diagnosis to distinguish normal from mildly affected individuals. Which of the following results would be expected in an individual with a promoter mutation at one COL2A1 gene locus?
A. Western blotting detects no type II collagen chains
B. Southern blotting using intronic restriction sites yields normal restriction fragment sizes
C. Reverse transcriptase“polymerase chain reaction (RT-PCR) detects one-half normal amounts of COL2A1 mRNA in affected individuals
D. Fluorescent in situ hybridization (FISH) analysis using a COL2A1 probe detects signals on only one chromosome 12
E. DNA sequencing reveals a single nucleotide difference between homologous COL2A1 exons
A. Western blotting detects no type II collagen chains
B. Southern blotting using intronic restriction sites yields normal restriction fragment sizes
C. Reverse transcriptase“polymerase chain reaction (RT-PCR) detects one-half normal amounts of COL2A1 mRNA in affected individuals
D. Fluorescent in situ hybridization (FISH) analysis using a COL2A1 probe detects signals on only one chromosome 12
E. DNA sequencing reveals a single nucleotide difference between homologous COL2A1 exons