Autosomal dominant autosomal recessive inheritance Flashcards
What did Gregor Mendel’s pea plants show
Principle of segregation and theory of independent assortment
What is the basic unit of heredity
Gene
What are genes made of
DNA
How many recessive genes do each of us carry for serious genetic conditions
4-8
What is a pedigree
Representation of a family history in graphic form
What does it mean if there is a square or circle with a line through it on a pedigree chart
Person is deceased
What does a triangle mean on a pedigree chart
Abortion
What do brackets mean on a pedigree chart
Adoption
What does a bracket with a straight line indicate on a pedigree chart
The baby was adopted out meaning somebody else is raising them
What do brackets with a dashed line on a pedigree chart indicate
Baby is not biological and was adopted in
Principle of segregation?
Says that genes occur in pairs and only one gene is transmitted to offspring from each parent. Traits are not blended. Only one trait is expressed
What is the principle of independent assortment say
Genes at different loci are transmitted independently
If a trait is autosomal dominant can unaffected family members pass on the gene
No
Does every affected person have an affected parent in autosomal dominant
Yes
Is there a male to male transmission in autosomal dominant traits
Yes.
Is postaxial polydactyly autosomal dominant or recessive
Dominant
What type of Disorder is usually only found in siblings like a horizontal pattern
Autosomal recessive
What type of disorder is albinism
Autosomal recessive
What type of disorder is phenylketonuria (PKU)
Autosomal recessive
What is phenylketonuria (PKU)
Individual cannot metabolize the amino acid phenylalanine
What type of disorder is cystic fibrosis
Autosomal recessive
What does cystic fibrosis affect
Chloride ion transport across cell membrane’s meeting to mucus buildup
What is quasidominant inheritance
When a person with an autosomal recessive disorder mates with a person who is a carrier for the same disorder
If someone who has one BRCA2 mutation what condition do they have
Hereditary breast and ovarian cancer syndrome (HBOC) Which increases their risk for breast, ovarian, and pancreatic cancer’s in adulthood
If someone has tow BRCA2 mutation what condition do they have
Fanconi anemia (FA)
What are the physical abnormalities of Fanconi anemia
Short stature, abnormal skin pigmentation, bone malformations
What are some other clinical manifestations of someone with fanconi anemia
Progressive Bone marrow failure and solid tumors
What is the protein like if someone is recessive for Familial isolated growth hormone deficiency
No protein is synthesized
What is the protein like if someone is dominant for Familial isolated growth hormone deficiency
An abnormal proteins synthesized ans blocks the function of the normal protein
What are those Who are heterozygous for sickle cell trait at an increased risk for
Splenic infarctions at a high altitude
What is a de novo mutation
When neither parent is affected And one of the genes transmitted by a parent underwent a change in the DNA sequence
What disorders are more prone to de novo mutations
Neurofibromastosis type 1, achondroplasia, familial adenomatous polyposis
What disorder are more prone to germline mosaicism
Osteogenesis imperfecta, achondroplasia, duchenne muscular dystrophy, hemophilia a
What is Germline mosaicism
When the mutation is present in a portion of the parents germline but not in other cells so they are unaffected
What is retinoblastoma
Childhood Eye tumor typically presenting at three months to four years
How is retinoblastoma typically transmitted
Most are somatic mutations in early development and are not inherited
What is the most common cause of death in Huntington disease
Aspiration pneumonia followed by cardiorespiratory failure and subdural hematoma
What type of disorder is Huntington’s disease
Autosomal dominant and triplet repeat
What is penetrance
All or none; one has the disease or does not
What is expression
Degree of severity of the disease phenotype. May only have 2/7 symptoms
Clinical manifestations of neurofibromatosis type one (NF-1)
Six or more café au lait macules 2 or more neurofibromas Axillary or groin freckling Osseous lesion such as pseudosrthritis Optic glioma Two or more iris lisch nodules First-degree affected relative
Allelic heterogeneity
Different types of mutations in the same gene can lead to different phenotypes or different disease severity
What are modifier loci
Genes that interact with each other to modify phenotype
What factors affect gene expression
Environmental factors, modifier loci, allelic heterogeneity
What is locus heterogeneity
Mutations in multiple genes can result in similar phenotypes
Give me some examples of locus heterogeneity
Lynch syndrome, osteogenesis imperfecta, autosomal dominant polycystic kidney disease
Pleiotrophy?
Genes that affect multiple parts of the body
Give it example of a disease that is pleiotrophic
Marfan syndrome
