A 6-year-old girl is referred to the Paediatric Clinic for failure to thrive. She has failed to maintain her weight and suffers from diarrhoea and frequent respiratory tract infections. A sweat test is performed and the chloride content of the sweat is 72 mmol/l.
Which of the following modes of inheritance fits best with this condition?
A 28-year-old woman visits her doctor concerned about her family’s history of inherited illnesses. Her grandmother experienced vision loss at the age of 70, while her mother began to have similar symptoms at the age of 50. What is the genetic mechanism responsible for the earlier age of onset in each generation?
A child is born with a genetic condition that is inherited in an autosomal dominant manner. The parents are informed of this. What is the most likely condition that the child has?
A 35-year-old woman attends her first antenatal appointment at 10 weeks’ gestation. This is her second pregnancy. She has a history of hypertension and is taking medication for it. She is offered antenatal screening for chromosomal abnormalities, including Down syndrome.
Which of the following tests is used in antenatal screening for Down syndrome?
A 32-year-old primigravid woman at twelve weeks gestation visits her obstetrician for a routine booking appointment. She has sickle cell anaemia. She has sickle cell anaemia. Her partner’s sickle cell status is Hb AS. Her haemoglobin is 92 g/l (normal range: 115–155 g/l).
What is the likelihood of her baby having sickle cell disease?
Given that PKU is an autosomal-recessive condition that can be diagnosed at birth or in adolescence and adulthood, a teenager seeks genetic counselling. His mother and brother have PKU, while his father is a carrier but does not have the disease. The teenager himself does not have PKU. What is the probability that he is a carrier of the disease?
A 3-year-old girl is referred to the paediatric clinic for failure to thrive. She has failed to maintain her weight and suffers from frequent vomiting and respiratory tract infections. A sweat test is performed and the chloride content of the sweat is 72 mmol/l (normal level <60 mmol/l).
Which of the following modes of inheritance fits best with this condition?
A 35-year-old man who is generally healthy visits his doctor to discuss planning a second child. His main concern is that his first child has sickle cell anemia. Both he and his partner have had genetic testing and are both carriers of the sickle cell trait.
Which of the following best describes the likelihood of his next child having sickle cell anemia?
A 30-year-old woman visits her doctor with worries about a genetic disorder. Her granddaughter, who is three years old, has been diagnosed with sickle cell anemia. She reports that no one else in the family has the condition.
What is the likelihood of her being a carrier of the sickle cell allele?
A 30-year-old man presents to the Genetic Counselling Clinic along with his wife. They are concerned about the possibility of their baby inheriting an autosomal-recessive genetic condition for which the man’s brother is affected. The carrier status of the wife is unknown.
Both the man and his wife are unaffected by the condition; the condition in question has a carrier rate of 1 in 100 in the general population.
What is the likelihood of the baby being affected by the condition?