Module 6 inheritance Patterns

Question 1

Autosomal Dominant + examples

Answer 1

1 affected, 1 abnormal
Polycystic kidney Disease,
Neurofibromatosis

Question 2

Autosomal Recessive

Answer 2

has to have homozygous genes

Albinism,
PKU (phenylketonuria)
Sickle Cell Anemia

Question 3

X-Linked Recessive

Answer 3

Only carried on X chromo.. Requires 2 copies to express unless opposed- xx or xY

Hemophilia A
Duchenne Muscular Dystrophy
Red/green color blindness

Question 4

Mitochondrial Inheritance

Answer 4

Variable presentation…
Typically comes from mom– 95% from ova

Leber Hereditary optic neuropathy (LHON)
Myoclonic epilepsy with ragged-red fiber syndrome (MERRF)

Question 5

Trinucleotide Repeat Disorder

Answer 5

Genetic mutations that are amplified in successive Generations–> increased severity in younger generations
… “repeats get larger and larger”

Fragile X syndrome
Freidrichs Ataxia
Huntingtons Chorea
Myotonic Dystrophy

Question 6

Genetic Inheritance: Recurrence Risk

Answer 6

Recurrence- Probability that a family will get same disease

Everyone has it?– all recessive, or a dominate trait
“skips a generation”- recessive, carrier

No history?: new, germ-line mutation, low penetrance (have a gene for it it but don’t get it

Question 7

Other modes of inheritance….

Answer 7

Sex limited/sex influenced
Y linked
X-linked dominant

Multifactorial disorders…

Question 8

Multifactorial Disorders:

Answer 8

Cleft lip/palate
Club foot
Neural tube defects
Alcoholism
Cancer
Diabetes
Heart disease
schizophrenia