A 28-year-old woman visits her doctor concerned about her family’s history of inherited diseases. Her grandmother experienced difficulty walking at the age of 63, while her mother began to show the same symptoms at the age of 40. What is the genetic mechanism responsible for the earlier age of onset in each generation?
A 32-year-old basketball player collapsed during a game and died from a ruptured aortic aneurysm. The athlete died from the consequences of a genetic defect called Marfan’s syndrome.
Which extracellular matrix protein is altered in this disease?
A 40-year-old woman is pregnant with her first child. She is offered screening for chromosomal abnormalities and an ultrasound assessment. She decides to proceed with testing, which assesses nuchal thickness, pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotrophin (β-hCG) and crown–rump length. She is told the pregnancy is high risk for Down syndrome, and she and her partner are offered an amniocentesis.
Which one of the following statements regarding amniocentesis is correct?
A 5-year-old girl is referred to the paediatric team by her GP as she has had numerous chest infections. The parents also mention that the girl has always had salty tasting skin. On checking the child’s growth chart, the GP notices that the child’s weight has fallen from the 50th centile at birth to the 9th centile currently. She is concerned that the child may have cystic fibrosis.
Which of the following statements best describes cystic fibrosis?
A 38-year-old woman comes in for her routine anatomy ultrasound scan at 20 weeks’ gestation. The ultrasound reveals significant fetal structural abnormalities, such as holoprosencephaly, cleft palate, short limbs, polydactyly, bilateral club feet, enlarged kidneys, and polyhydramnios.
What is the probable underlying diagnosis of the unborn child?
An astute pathologist examines tissue from a spontaneous abortion and observes the existence of mature fetal tissue that contains Barr bodies. What possible genotypes could the fetus have had?
A 63-year-old man presents with fatigue, weakness, tachycardia and generalised pallor, along with an unintentional weight loss of 10 pounds. He has been experiencing frequent constipation and has noticed streaks of red blood on the surface of his stools over the past year. His family history is notable for a history of colorectal cancer. Upon examination, a mass is palpated on the left lower abdominal quadrant. The barium enema reveals an apple-core lesion of the descending colon, and there are enlarged lymph nodes and foci of liver metastasis on the abdominal CT scan. The serum carcinoembryonic antigen is significantly elevated. Molecular genetic studies have revealed a mutation in a gene located on the short arm of chromosome 12.
Which gene is most likely affected by this mutation?
A 50-year-old man is being evaluated after being hospitalized six weeks ago for an inferior myocardial infarction that was treated with thrombolysis. He has been prescribed atenolol 50 mg daily, aspirin, and rosuvastatin 10 mg daily upon discharge. He has quit smoking after his MI and is now curious about which foods he should steer clear of.
Which of the following foods should he avoid?
A 14-year-old girl comes to see you, the practice nurse, after getting an open wound on her right arm while playing basketball. Upon examination, you find a 5 cm wound that is dirty and contains dirt. What is the best course of action for tetanus vaccination in this patient?
A 9-month-old infant comes to the clinic with a complaint of fever (39°C) and a rash that started on the legs and has now spread to the limbs and trunk. The rash is purplish, non-palpable, and non-blanching. What is the most probable diagnosis?