Modes of Inheritance

(M1.BC.17.4708) An 11-year-old male is brought to his pediatrician for continuing management of a chronic lung infection. He has had many lung infections throughout childhood, and current sputum samples show oxidase positive, non-lactose fermenting gram-negative rods that produce a blue-green pigment. Physical exam shows nasal polyps and nail clubbing. He has also recently been experiencing floating foul smelling diarrhea, so he is prescribed enzymes and vitamin supplementation tablets. Which of the following chromosomes most likely contains the gene mutation responsible for this patient's symptoms?

(M1.BC.15.73) A pregnant woman presents to your office with concerns regarding the risk that her fetus will suffer from an inherited disease. She reports a family history of hemophilia A in several of her relatives. Figure A shows a pedigree created after a thorough review of her family history (the pregnant woman in this scenario is represented by the arrow). This is her first child, and the father does not report any family history of blood disorders or other diseases. Which of the following is the probability that this woman's male offspring will have hemophilia A?

(M1.BC.15.73) A 1-year-old boy with blonde hair, blue eyes, and fair skin is found to have mental retardation, eczema, and vomiting. A mousy body odor is apparent. Which of the following pedigrees best resembles the inheritance pattern of this disease?

(M1.BC.15.1) A 19-year-old male presents to the university health clinic after a year of daily jerking in his limbs and experiencing a tonic clonic seizure witnessed by his roommate earlier today. He had been too embarrassed to come discuss his myoclonus, but he noticed that it had been increasing in frequency over the past few months. He noted that he tires very quickly when exercising, has poor vision and hearing, and was told that his mother, who passed away at his birth, also had similar symptoms. The physician sends for a muscle biopsy, which shows the following Gömöri trichrome stain (Figure A). What is the mode of inheritance of this disorder?

(M1.BC.15.0) A 5-year-old boy with a history of seizures presents to the pediatrician for several seizures occurring over the past month. The mother states that her son typically avoids recess, as he exhausts quite easily with any physical activity. He has also had headaches and vomits after he eats. A family history reveals that a maternal uncle and grandmother both had similar symptoms and both lost their vision and hearing by the age of 40. The mother explains that she also tires easily. With consent of the mother, a muscle biopsy was taken and a Gömöri trichrome stain was performed (Figure A). A blood analysis also revealed significantly elevated lactate levels. Which of the following statement best describes the mode of inheritance of the boy's disease?

(M1.BC.14.44) A 34-year-old male suffers from inherited hemophilia A. He and his wife have three unaffected daughters. What is the probability that the second daughter is a carrier of the disease?

(M1.BC.14.27) The incidence of red-green color blindness in males in a certain population is 1/100. Which of the following is closest to the probability of a female and a male with normal vision having a daughter with red-green color blindness?

(M1.BC.14.2) A 27-year-old G1P0 at 12 weeks gestation presents to her obstetrician for her first prenatal visit. She and her husband both have achondroplasia, and she is curious what are the chances that they will have a child of average height. What percent of pregnancies between two individuals with achondroplasia that result in a live birth will be expected to be offspring that are unaffected by this condition?