Biochem - Genetics (Autosomal-dominant diseases) Flashcards Preview

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Flashcards in Biochem - Genetics (Autosomal-dominant diseases) Deck (33):

What was the former name of Autosomal dominant polycystic kidney disease (ADPKD)?

Formerly known as adult polycystic kidney disease


What is the main presentation of ADPKD, and what causes this?

Always bilateral, massive enlargement of kidneys due to multiple large cysts


What mutations cause ADPK? On what chromosomes are they? What percentage of cases are attributed to each of these?

85% of cases are due to mutation in PKD1 (chromosome 16; Think: "16 letters in polycystic kidney"); Remainder due to mutation in PKD2 (chromosome 4)


What defines familial adenomatous polyposis, and when does it occur?

Colon becomes covered with adenomatous polyps after puberty


To what does familial adenomatous polyposis progress? How is this progression prevented?

Progresses to colon cancer unless colon is resected


What mutation and chromosome are associated with familial adenomatous polyposis?

Mutations on chromosome 5 (APC gene); Think: "5 letters in 'polyp'"


What is the defect in familial hypercholesterolemia, and what effect does it have?

Elevated LDL due to defective or absent LDL receptor


What are the 2 main clinical findings caused by familial hypercholesterolemia?

Leads to severe atherosclerotic disease early in life, and tendon xanthomas (classically in the Achilles tendon)


What is Hereditary hemorrhagic telangiectasia? What is another name for it?

Inherited disorder of blood vessels; Also known as Osler-Weber-Rendu syndrome


What are 6 clinical findings associated with hereditary hemorrhagic telangiectasia?

Findings: (1) telangiectasia (2) recurrent epistaxis (3) skin discolorations (4) atriovenous malformations (AVMs) (5) GI bleeding (6) hematuria


What is the defect in hereditary spherocytosis, and what effect does it have?

Spheroid erythrocytes due to spectrin or ankyrin defect


What are 2 clinical/lab findings associated with hereditary spherocytosis?

Hemolytic anemia; high MCHC


What is the treatment for hereditary spherocytosis?

Treatment: splenectomy


What are 5 clinical/lab findings associated with Huntington disease?

Findings: (1) depression, (2) progressive dementia, (3) choreiform movements, (4) caudate atrophy, and (5) low levels of GABA and ACh in the brain


On what chromosome is the Huntington gene?

Gene on chromosome 4; Think: "Hunting 4 food"


What kind of repeats are associated with Huntington disease? What effect do increasing number of repeats have?

Trinucleotide repeat disorder: (CAG)n. Increased repeats --> Decreased age of onset


What is the defect in Marfan syndrome, and what effects does it have?

Fibrillin-1 gene mutation --> connective tissue disorder affecting skeleton, heart, and eyes


What are 4 physical findings associated with Marfan syndrome?

Findings: (1) tall with long extremities (2) pectus excavatum (3) hypermobile joints (4) Long, tapering fingers and toes (arachnodactyly)


What aortic finding is associated with Marfan syndrome, and what causes it?

Cystic medial necrosis of aorta --> aortic incompetence and dissecting aortic aneurysms


What cardiac finding is associated with Marfan syndrome?

Floppy mitral valve


What ocular finding is associated with Marfan syndrome?

Subluxation of lenses, typically upward and temporally


What is MEN, and what are the types of MEN? In general, what characterizes them?

Multiple endocrine neoplasias (MEN); Several distinct syndromes (1, 2A, 2B) characterized by familial tumors of endocrine glands, including those of the pancreas, parathyroid, pituitary, thyroid, and adrenal medulla.


Which what gene is MEN 2A associated? What other type of MEN is also associated with this gene?

MEN 2A and 2B are associated with ret gene


What is another name for Neurofibromatosis type 1?

Neurofibromatosis type 1 (von Recklinghausen disease)


What is Neurofibromatosis type 1, and what 2 main physical findings characterize it?

Neurocutaneous disorder characterized by cafe-au-lait spots and cutaneous neurofibromas


What is the mode of inheritance, penetrance, and expression of neurofibromatosis type 1?

Autosomal dominant, 100% penetrance, variable expression


What gene mutations cause Neurofibromatosis type 1, and on what chromosome is the gene found?

Caused by mutations in the NF1 gene on chromosome 17; Think: "17 letters in 'von Recklinghausen'"


What are 4 clinical findings associated with Neurofibromatosis type 2?

Findings: (1) bilateral acoustic schwannomas (2) juvenile cataracts (3) meningiomas (4) ependymomas


What gene mutations cause Neurofibromatosis type 2, and on what chromosome is the gene found?

NF2 gene on chromosome 22; Think: "type 2 = 22"


What is Tuberous sclerosis, and what finding characterizes it?

Neurocutaneous disorder with multi-organ system involvement, characterized by numerous benign hamartomas


What is the penetrance and expression of Tuberous sclerosis?

Incomplete penetrance, variable expression


What characterizes von Hippel-Lindau disease?

Disorder characterized by development of numerous tumors, both benign and malignant


With what mutation is von Hippel-Lindau disease associated, and on what chromosome is this gene found?

Associated with deletion of VHL gene (tumor suppressor) on chromosome 3 (3p); Think: "Von Hippel-Lindau = 3 words for chromosome 3"

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