Genetic counseling for lysosomal diseases — MCQs

A 28-year-old woman comes to the physician for genetic counseling prior to conception. For the past year, she has had intermittent episodes of headache, nausea, abdominal pain, and tingling of her fingers. She also complains of dark urine during the episodes. Her mother and maternal uncle have similar symptoms and her father is healthy. Her husband is healthy and there is no history of serious illness in his family. Serum studies show elevated concentrations of porphobilinogen and δ-aminolevulinic acid. What is the probability of this patient having a child with the same disease as her?

A 7-year-old boy is brought to the emergency department by his parents. He is complaining of left-sided knee pain which has progressively increased in severity over the past 2 days. It started when he was playing football with his brothers but he does not recall falling or getting any injury. Past medical history is significant for prolonged bleeding and easy bruising. His maternal uncle has similar problems. Physical exam reveals swollen and painful left knee. His laboratory investigations reveal: Hemoglobin 11.8 g/dL WBC count 7,000/mL Platelets 250,000/mL INR 0.9 aPTT 62 sec, fully corrected with a mixing study Which of the following disorders have the same mode of inheritance as this patient’s disease?

A healthy 30-year-old woman comes to the physician with her husband for preconception counseling. Her husband is healthy but she is concerned because her brother was recently diagnosed with a genetic liver condition for which he takes penicillamine. Her father-in-law has liver cirrhosis and a tremor. The results of genetic testing show that both the patient and her husband are carriers of a mutation in the ATP7B gene. Which of the following is the chance that this patient’s offspring will eventually develop the hereditary condition?

A 34-year-old woman, gravida 1, para 0, at 18 weeks' gestation, comes to the physician for a prenatal visit. She recently read about a genetic disorder that manifests with gait ataxia, kyphoscoliosis, and arrhythmia and is concerned about the possibility of her child inheriting the disease. There is no personal or family history of this disorder. The frequency of unaffected carriers in the general population is 1/100. Assuming the population is in a steady state without selection, what is the probability that her child will develop this disease?

A 3-year-old is brought to the pediatrician by his mother because she is concerned about recent changes to his behavior. She states that he has seemed to regress in his motor development and has been having occasional brief episodes of uncontrollable shaking. During the subsequent work up, a muscle biopsy is obtained which demonstrates red ragged fibers and a presumptive diagnosis of a genetic disease made. The mother asks if her other son will be affected. What should be the physician's response?

A 28-year-old woman, gravida 1, para 0, at 20 weeks' gestation comes to the physician for genetic counseling. Her brother and maternal uncle both have anemia that worsens after taking certain medications. Based on the pedigree shown, what is the probability that her son will be affected by the disease?

A 7-month-old boy is brought to the pediatrician by his parents due to progressively worsening weakness for the last three months. The parents also describe the boy as having an exaggerated response when startled as well as diminishing response to visual stimuli. At birth, the boy was healthy and remained as such for the first few months of life. The mother says pregnancy was unremarkable, and the boy was born at 39 weeks with no complications during delivery. He is up to date on his vaccinations. The boy's grandparents immigrated from an eastern European country. Physical examination reveals hyperreflexia. Abdominal examination reveals no abnormalities. On fundoscopy, the following is seen. Which of the following is most likely deficient in this patient?

An 18-month-old girl is brought to the pediatrician’s office for failure to thrive and developmental delay. The patient’s mother says she has not started speaking and is just now starting to pull herself up to standing position. Furthermore, her movement appears to be restricted. Physical examination reveals coarse facial features and restricted joint mobility. Laboratory studies show increased plasma levels of several enzymes. Which of the following is the underlying biochemical defect in this patient?

An investigator is studying the outcomes of a malaria outbreak in an endemic region of Africa. 500 men and 500 women with known malaria exposure are selected to participate in the study. Participants with G6PD deficiency are excluded from the study. The clinical records of the study subjects are reviewed and their peripheral blood smears are evaluated for the presence of Plasmodium trophozoites. Results show that 9% of the exposed population does not have clinical or laboratory evidence of malaria infection. Which of the following best explains the absence of infection seen in this subset of participants?

A 75-year-old Caucasian man presents to the emergency department with abdominal pain. The patient states he was at home eating dinner when he began to experience severe abdominal pain. The patient has a past medical history of diabetes, hypertension, and atherosclerosis. He lives at home alone, smokes cigarettes, and drinks 1 to 2 alcoholic drinks per day. The patient is given IV morphine and an ultrasound is obtained demonstrating a dilated abdominal aorta. The patient states that his father died of a similar finding and is concerned about his prognosis. Which of the following is the greatest risk factor for this patient's presentation?