A 34-Year-Old Man Is Found to Have an LDL Level

question 129

Multiple Choice

A 34-year-old man is found to have an LDL level of 310 mg/dL and a normal serum triglyceride level.  His father suffered a myocardial infarction at age 39, and his paternal grandfather died of a heart attack at age 40.  The patient's wife has a normal lipid profile.  DNA samples are obtained from several family members for genetic analysis.  Southern blotting of restriction fragments from a region containing the LDL receptor gene shows the following pattern: Which of the following statements best describes the DNA analysis results?

• A)The disease is transmitted in an X-linked recessive fashion
• B)The mutation is probably located in the 10 kb band
• C)The mutation is probably located in the 12 kb band
• D)The patient's brother most likely inherited the mutation
• E)The patient's son most likely inherited the mutation