Genetics Flashcards
Familial Hypercholestoremia
Autosomal dominant leading to LDL deficiency
Huntington’s Disease
Autosomal dominant-triplet repeat disorder. Gain of function mutation.
Myotonic Dystrophy
Autosomal Dominant. DMPK mutation, highly pleiotropic.
Achondroplasia
Autosomal dominant. Deficient in FGFR3 (growth factor). Relatively normal life span.
Marfan’s Syndrome
Mutation in Fibrillin-1 gene. Autosomal dominant. Pleiotropic. Dominant negative mutation.
Osteogenesis Imperfecta
Autosomal dominant. Brittle bone syndrome.
Neurofibromatosis
Autosomal Dominant. Mutation in NF-1 gene, NF-1 codes for nuerofibrillin which is a tumor suppressor gene. Has variable expressivity-some have cafe au lait spots and other have small tumors all over the body, and Lisch nodules in the eyes. Allelic heterogeneity.
Acute Intermittent Porphyria
Autosomal dominant. Causes an enzyme deficiency, one of the only AD that do that.
Cystic Fibrosis
Mutation in the CFTR gene.
Sickle Cell Anemia
Autosomal Recessive
Phenylketonuria (PKU)
Autosomal Recessive
Tay Sachs Disease
Hexosaminidase A deficiency. Autosomal recessive.
Congenital Deafness
Autosomal recessive
Hemochromatosis
Build up of iron in the body. Autosomal recessive. Delayed age of onset. Allelic heterogeneity.
Alkaptonuria
Delayed age of onset. Autosomal recessive.
Homocystinuria
Autosomal recessive.
Galactosemia
Autosomal recessive
Alpha 1-antitrypsin deficiency
Autosomal recessive
SCID due to adenosine deaminase deficiency
Autosomal recessive
What is the molecular basis for most autosomal recessive disorders?
Loss of function mutations (e.g., enzyme deficiencies) is
Pseudo-autosomal dominant disorder
An autosomal recessive condition that is present in two or more generations in the family, looking like its following a dominant inheritance pattern. Seen when there is a high carrier frequency (sickle cell) and high incidence of consanguinity
X-linked recessive disorders (female)
Very rare in the population, color blindness is the only known one.
X-linked recessive
More common in males, skipping generations is common, fathers give disease allele to carrier daughters who give to affected sons. No male to male transmission.
Duchenne Muscular Dystrophy
Severe form, early on set, short life span. Low genetic fitness so men who have it don’t usually live long enough to pass it on. Muscle is replaced by adipose. Due to loss of the dystrophin protein. X-linked recessive.