Step 1 - Biochem 2rename
denniskwinn's version from 2015-04-25 15:56
|Hardy weinberg population genetics||1. Disease prevalence: p^2+2pq+q^2=1|
2. Allele prevalence p+q=1
3. 2pq=heterozygote prevalence
4. Presence of x linked recessive disease in males =q, females = q*q
|Hardy weinberg assumptions||1. No mutations occur at the locus|
2. No selection for any of the genotypes at the locus
3. Completely random mating
4. No migration
|Prader willi and anglemans||-Prader willi from deletion of normally active Paternal allele|
-Angelmans from deletion of Maternal alleles
-Both Deletions=Chromosome 15
|Prader willi characterization||MEntal retardations, hyperphagia, obesity, hypogonadism, hypotonia|
|Angelman’s syndrome characteristics||Mental retardation, seizures, ataxia, inappropriate laughter (happy puppet)|
|Autosomal dominant||-Often due to defects in structural genes. Many generations, both male and female, affected. Often pleiotropic and in many cases, present clinically after puberty. |
-Family history crucial to diagnosis.
|Autosomal recessive||-25% of offspring from 2 carrier parents|
-Often due to enzyme deficiencies
-Usually seen in only 1 generation
-Commonly more severe than dominant disorders; patients often present in childhood
|X-linked recessive||Sons of heterozygous mothers have 50% chance of being affected (no male to male transmission) - commonly more severe in males - homozygous females may be affected.|
|X-linked dominant||Transmitted through both parents - either male or female offspring of affected mother may be affected while all female offspring of affected father are diseased - Example hypophosphatemic rickets|
|Mitochondrial inheritance||All offspring of effected females may show signs of disease|
|Achondroplasia||-Autosomal dominant |
-Cell-signaling defect of FGF receptor 3.
-Results in dwarfism; short limbs, but head and trunk arc normal size.
- Associated with advanced paternal age.
|Autosomal dominant polycystic kidney disease (ADPKD)||-Formerly known as adult polvcystic kidnev disease. -Always B/L, massive enlargement of kidneys due to multiple large cysts. |
-Patients present with flank pain, hematuria, hypertension, progressive renal failure.
- 90% of cases are due to mutation in APKD1 (chromosome 16; 16 letters in "polycystic kidney"). -Associated w/polycystic liver disease, berry aneurysms, mitral valve prolapse, infantile form is recessive.
|Familial adenomatous polyposis||-Autosomal dominant, colon becomes covered with adenomatous polyps after puberty. Progresses to colon cancer unless resected. |
-Mutation on chromosome 5 (APC genes)
( 5 letters in polyp)
|Familial hypercholesterolemia (hyperlipidemia type IIA)||Autosomal dominant|
-Elevated LDL due to defective or absent LDL receptor.
-Heterzygotes (1:500) have cholesterol of 300mg/dL, homozygotes (very rare) have 700+mg/dL, severe atherosclerotic disease early in life and tendon xanthomas (A`chilles)
- MI may develop before age 20
|Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)||Autosomal dominant Inherited disorder of blood vessels. Findings: telangiectasia, recurrent epitaxis, skin discoloration, AV malformations|
|Hereditary spherocytosis||-Autosomal dominant|
- Spheroid RBCs due to spectrin or ankyrin defect → hemolytic anemia
- ↑MCHC, splenectomy is curative (for the hemolysis)
|Huntingdon’s disease||-Autosomal dominant trinucleotide repeat disorder |
- Gene 4 location CAG repeats.
-Findings: depression, progressive dementia, choreiform movements, caudate atrophy, ↓GABA and ACh in brain. Sx manifest b/w 20 and 50y
(Hunting 4 food)
|Marfan’s syndrome||-Autosomal dominant|
-Fibrillin gene mutation→ connective tissue disorder affecting skeleton, heart and eyes. Tall w/long extremities, pectus excavatum, hyperextensive joints and long, tapering fingers and toes (arachnodactyly), cystic medial necrosis of aorta→aortic incompetence and dissecting aortic aneurysms; floppy mitral valve - subluxation of lenses
|Multiple endocrineneoplasia||-Autosomal dominant syndromes characterized by familial tumors of endocrine glands|
- MEN2A and B associated with ret gene(RB)
|Neurfibromatosis 1 (von RecklingHAUSEn’s disease)||-Autosomal dominant|
-"CAFE SPOT" :
Café au lait spots
Eye- Lisch nodules
Positive family history
-On long arm of chromosome 17; (17 letters in von Recklinghausen)
|Neurofibromatosis 2||Autosomal dominant: |
MISME Too is
M - Multiple
I - Inherited
S - Schwannomas (vestibular and spinal)
M - Meningioma
E - Ependymoma
-NF2 gene on chromosome 22
- (type 2=22)
Tu=tuber calcification(of the perivent) and tumor (malig astrocytoma)
B= blood in urine(hematuria)
O=off white skin (ash,hypo-pigmented skin lesions)
S=shagreen and sebaceous adenoma..
(the t and the s ..the beginning and the end are double letters)
|Von Hippel-lindau disease||-Autosomal dominant |
Hemanigoblastomas(eye, cerebellum, medulla)
Increased renal cancer(RCC)
Liver, pancreas, kidney cysts
· Bare bones version: Hippel-Lindau, with H and L as above.
-A/w with deletion of VHL gene (tumor suppressor) on chromosome 3 (3p)→ constitutive expression of HIF transcription factor and activation ofangiogenic GFs
- Von Hippel Lindau = 3 words = chromosome 3