Some Genetic Diseases from First Aid Biochem Flashcards Preview

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Flashcards in Some Genetic Diseases from First Aid Biochem Deck (30)
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1
Q

Achondroplasia

A

autosomal dominant mutation in FGFR3 inhibits chondrocyte proliferation. Full penetrance.

2
Q

ADPKD

A

bilateral enlargement of kidneys due to cysts. 85% of cases are due to mutation in PKD1 (chromosome 16, 16 letters in “polycystic kidney”). Remainder due to PKD2. Autosomal dominant.

3
Q

FAP

A

familial adenomatous polyposis. colon becomes covered with adenomatous polyps after puberty. Colon must be resected or 100% progress to colon cancer. Mutation is at chromosome 5q (APC gene) (5 letters in “polyp”). Autosomal dominant.

4
Q

Familial Hypercholesterolemia

A

Elevated LDL due to due to defective or absent LDL receptor. Severe atherosclerotic disease early in life, corneal arcus, tendon xanthomas (classically the achilles tendon). Autosomal dominant.

5
Q

Hereditary Hemorrhagic Telangiectasia

A

telangiectasias, recurrent epistaxis, skin discoloration, AVMs, Gi bleeding, hematuria. AKA Osler-Weber- Rendu syndrome. Autosomal dominant.

6
Q

Huntington Disease

A

depression, progressive dementia, choreiform movements, caudate atrophy. Trinucleotide repeat disorder of gene on chromosome 4 (CAG repeats). Autosomal dominant with anticipation. increase number of repeats, decrease age of onset.

7
Q

Li-Fraumeni syndrome

A

abnormalities in TP53. multiple malignancies at an early age. Also known as SBLA cancer syndrome (sarcoma, breast, leukemia, adrenal gland). Autosomal dominant.

8
Q

Marfan syndrome

A

FBN1 mutation on chromsome 15 leading to defective fibrillin (the scaffold for elastin. Tall with long extremities, pectus excavatum, hypermobile joints, tapering of fingers and toes (arachnodactyly); cystic medial necorsis of the aorta. Aortic incompetence leads to dissection. Autosomal dominant.

9
Q

MEN

A

MEN 1 associated with MEN1 gene. MEN 2A and 2B associated with RET gene. Autosomal dominant.

10
Q

MEN1

A

hyperparathyroidism
pituitary adenoma
pancreatic tumors (especially

11
Q

MEN 2A

A

hyperparathyroidism
pheochromocytoma
medullary thyroid cancer

12
Q

MEN 2B

A

marfan
medullary thyroid cancer
pheochromocytoma

13
Q

NF1

A

cafe-au-lait spots, cutaneous neurofibromas, optic gliomas, pheo, Lsich nodules (pigemented iris hamartomas). 100% penetrance, variable experssion. autosomal dominant . mutation on NF1 gene on chromomsome 17. 17 letters in von Recklinghausen.

14
Q

NF2

A

bilateral acoustic schwannoma, juvenile cataracts, NF2 gene on chromsome 22. 2 –> 22. autosomal dominant.

15
Q

Tuberous Sclerosis

A

Neurocutaneous disorder. autosomal dominant.

16
Q

von Hippel-Lindau disease

A

characterized by the development of numerous tumors. both benign and malignant. associated with deletion of VHL gene (tumor suppressor) on chromosome 3P. 3 words Von hippel lindau –> chromosome 3.

17
Q

some autosomal recessive diseases

A

albinism, cystic fibrosis, glycogen storage disease, hemochromatosis, kartegener syndrome, PKU, sickle cell anemia, thalassemias, Wilson disease

18
Q

Cystic Fibrosis - genetic defect

A

CFTR gene defect on chromsome 7. often deletion of Phe508. most common lethal genetic disease in caucasian population.

19
Q

Cystic Fibrosis - pathophysiology

A

CFTR codes for ATP gated Cl channel. This channel secretes Cl in lungs and GI tract, reabsorbs Cl- in sweat glands. Phe508 deletion leads to misfolded protein, protein retained in RER, leading to decreased Cl (and H2O) secretion. Abnormally thick mucus secreted in the lungs.

20
Q

Cystic fibrosis - complications

A

recurrent pulmonary infections (staph aureus in infancy and pseudomonas as teenager).

pancreatic insufficiency. malabsorption, A, D, E, K vitamin deficiency (fat soluble).

Infertility in men

nasal polyps and clubbing of nails

21
Q

cystic fibrosis - diagnosis

A

chloride sweat test (>60 meq)

22
Q

X-linked recessive disorders (w/ mnemonic)

A
Oblivious Female Will Often Giver Her Boys Her x-Linked Disorders 
Ornithine transcarbamylase deficiency 
Wiskott-Aldrich 
Ocular albinism 
G6PD
Hunter syndrome 
Bruton agammaglobulinemia 
Hemophilia A and B
Lesch Nyhan Syndrome 
Duchenne (and becker muscular dystrophy)
23
Q

Duchenne Muscular dystrophy

  • cause
  • clinical findings
  • lab findings
  • diagnosis
A

frameshift or nonsense mutation leading to truncated dystrophin, inhibited muscle regeneration.

  • pseudohypertrophy of the calves
  • gower

increase CK and aldolase are seen. Western blot and muscle biopsy confirm the diagnosis.

24
Q

Becker muscular dystrophy

A

due to non frameshift insertions in dystrophin gene. partially. leads to a partially functional protein. less severe disease course. onset in teenage years or early adulthood instead of early childhood.

25
Q

Trinucleotide repeat expansion diseases

A
Huntington disease (CAG)
Freidrich ataxia (GAA)
Fragile X (CGG)
Myotonic dystrophy (CTG)
26
Q

Trisomy 18
name of syndrome
clinical features
prognosis

A

Edwards Syndrome
Severe intellectual disability, rocker bottom feet, micorgnathia, low set ears, clenched hands with overlapping fingers, congenital heart disease.
Death usually within 1 yr of birth

27
Q

Trisomy 13
name of syndrome
clinical features
prognosis

A

Patau Syndrome
severe intellectual disability, rocker bottom feet, micorcpehaly, cleft lip/palate, holoprosencephaly, polydactyly,
death usually occurs within 1 year of birth

28
Q

Trisomy 21
name of syndrome
clinical features

A

Down Syndrome
intellectual disability, flat facies, prominent epicanthal folds, single palamar crease, sandal gap toes, duodenal atresia, hirshcprung disease, congenital heart defect (ASD), associated with early onset alzheimers, increased risk of AML and ALL.

95 percent of cases are due meiotic non-disjunction
4 percent of cases are due to unbalanced robertsonian translocation (between 14 and 21).

29
Q

Cri-du-chat

A

congenital microdeletion of the short arm of chromsome 5.
microcephaly, moderate to severe intellectual disability, high pitched crying, epicanthal folds, cardiac abnormality (VSD).

30
Q

Williams syndrome

A

congenital microdeletion of the long arm of chromsome 7. distinctive “elfin” facies, intellectual disability, hypercalcemia, extreme friendliness with strangers