Clinical Genetics - Lecture 1

ABO blood groups. How many genotypes?

If both parents are carriers of mutant recessive allele, what is the risk for their offspring:
a. 25% for a healthy child being a homozygote for normal allele
b. 25% for a child being homozygote for the mutant allele
c. 50% for healthy child being a carrier
d. All of the above
e. B and C

AD inheritance is characterized by:
a. There is high incidence of parental consanguinity
b. Usually both parents are affected
c. The risk for the offspring depends on the sex of the child
d. All of the above
e. None of the above

XR inheritance is characterized by
a. All daughters of affected father will be obligatory carriers
b. Trait is transmitted by normal mother who is a carrier to all her sons
c. Affected males will transmit the trait to half of his sons
d. All of the above
e. None of the above

Non-Mendelian inheritance is observed in all of the following except:
a. A germinal mosaicism
b. Somatic mosaicism
c. Mitochondrial DNA transmission
d. Uniparental disomy
e. Genomic imprinting

Which of the following symptoms is usually not observed in diseases due to mitochondrial mutations
a. Hydrocephalus
b. Deafness
c. Cerebellar ataxia
d. Blindness
e. Heart block

Genomic imprinting is characterized by:
a. Gene expression is determined by the sex of the child
b. Represents mutation of gene’s promoter
c. Represents an epigenetic phenomenon related to the hypermethylation of DNA
d. All of the above
e. None of the above

Which of the following statements about UPD is true:
a. May occur as isodisomy or heterodusomy
b. Paternal disomy of chromosome 15 is observed in Angelman
c. Maternal dusomy of chromosome 15 is observed in PRader-Willi syndrome
d. The origin of isodisomy is during 1st meiotic division
e. All of the above

Indicate false statement
a. Hjomo and heteroplasmy refer to mitochondrial disorders
b. Uniparental heterodiusomy is due to chromosomal nondisjunction during 1st meiotic division
c. Genomic imprinting occurs when DNA is hypomethylated
d. 70% of Angelman syndrome is due to maternal chomrosme 15 deletion