Genetics E1- Medical Pedigree

What is a family tree that records relevant family information in a diagram?

Pedigree

What term refers to the person through whom the family came to medical attention?

Index case or proband

What term refers to the patient seeking genetic counseling?

Consultand

What kind of inheritance manifests in heterozygous state (abnormal phenotype), possessing both a variant and normal allele, and is observed in a vertical pattern affecting multiple generations?

Autosomal dominant

How is autosomal dominant inheritance confirmed?

Male-male transmission has occurred (father to son)

*male and female offspring equally affected

In autosomal dominant inheritance, what is the chance that the offspring would have the affected phenotype if an affected person mates with an unaffected person?

50%

What kind of inheritance is observed in a horizontal pattern, affected a single generation & males and females equally?

Autosomal recessive

With autosomal recessive inheritance, what are the chances that the offspring would be affected if each parent is a heterozygote (unaffected carrier)?

25% chance of being affected

25% chance of inheritance neither mutant allele

50% chance of being a carrier

With autosomal recessive inheritance, what are the chances that the offspring would be affected if one parent has the phenotype (homozygous) and one is a carrier (heterozygous)?

50% will be affected, 50% will be carriers

*pseudodominance

With autosomal recessive inheritance, what are the chances that the offspring will be affected if both parents have the phenotype?

100% will have phenotype

With autosomal recessive inheritance, what are the chances that the offspring will be affected if one parent has the phenotype and one parent is unaffected?

100% will be asymptomatic carriers

What type of inheritance has no male-male transmission, and all daughters of affected males would be heterozygous carriers?

X-linked transmission

How would heterozygous females of x-linked inherited conditions transmit the mutant to their offspring?

50% of sons affected and 50% of daughters are heterozygotes

What type of inheritance is almost exclusively from the mother through the oocyte?

Mitochondrial inheritance

What has been proposed as being responsible for some of the somatic effects seen with aging?

Accumulation of variants in mitochondrial DNA

What suggests X-linked recessive inheritance?

100% incidence of affected sons from an affected mother

What suggests X-linked dominant inheritance?

100% incidence of affected daughters from an affected father

What are first degree relatives?

Parents, siblings, children

What are second degree relatives?

Half-siblings, aunts, uncles, grandparents, nieces, nephews

What are third degree relatives?

First cousins