Biochem mutations Flashcards
MOA of hydroxyurea
- inhibits ribonucleotide reductase
MOA of 6MP
- blocks de novo purine synthesis
MOA of 5-FU
- inhibits thymidylate synthase (decreased dTMP)
MOA of methotrexate
- inhibits dihydrofolate reductase (decreased dTMP)
MOA of trimethoprim
- inhibits bacterial dihydrofolate reductase (decreased dTMP)
enzyme deficient in Lesch-Nyhan syndrome
- HGPRT
- presents with MR, self-mutilation, aggression, hyperuricemia (orange sand crystals), and gout
enzyme deficient in SCID
- adenosine deaminase
- presents with recurrent infections and decreased lymphocyte count
mutation found in xeroderma pigmentosum
- nucleotide excision repair
mutation found in HNPCC
- mismatch repair
mutation found in ataxia telangiectasia
- nonhomologous end joining
enzyme inhibited by Amanita phalloides mushrooms
- RNA polymerase II
cause of I-cell disease
- failure of addition of mannose-6-phosphate to lysosome proteins
mutation found in Chediak-Higashi
- mutation found in the lysosomal trafficking regulator gene (LYST)
mutation found in Kartagener’s
- immotile cilia due to a dynein arm defect
cause of osteogenesis imperfecta
- abnormal type I collagen
cause of Ehlers-Danlos
- defective collagen, most often types I or V
cause of Alport syndrome
- defective type IV collagen
mutation found in Marfan’s
- caused by a defect in fibrillin (fibrillin-1 gene)
blotting procedures
- SNoW DRoP
- Southern= DNA
- Northern= RNA
- Western= Protein
- Southwestern=DNA-binding proteins
cause and presentation of Prader-Willi syndrome
- paternal allele is not expressed on chromosome 15
- mental retardation, hyperphagia, obesity, hypogonadism, hypotonia
cause and presentation of Angelman’s syndrom
- maternal allele is not expressed on chromosome 15
- MR, seizures, ataxia, inappropriate laughter
mutation found in achondroplasia
- fibroblast growth factor receptor 3
mutation found in ADPKD
- PDK1 on chromosome 16
mutation found in familial adenomatous polyposis
- APC gene on chromosome 5
mutation found in familial hypercholesterolemia
- defective or absent LDL receptor
mutation found in hereditary spherocytosis
- spectrin or ankryin defect
mutation found in NF type 1
- long arm of chromosome 17
mutation found in NF type 2
- NF2 gene on chromosome 22
mutation found in von-Hippel-Lindau disease
- VHL gene (tumor suppressor) on chromosome 3p
mutation found in CF
- CFTR gene on chromosome 7
mutation found in Duchenne’s and Becker’s MD
- dystrophin
4 diseases associated with trinucleotide repeats
- Fragile X: CGG
- Friedreich’s ataxia: GAA
- Huntington’s: CAG
- Myotonic dystrophy: CTG
mutation found in Cri-du-chat syndrome
- microdeletion of short arm of chromosome 5
mutation found in William’s syndrome
- microdeletion of long arm of chromosome 7
mutation found in DiGeorge’s
- 22q11 deletion
enzyme deficient in essential fructosuria
- fructokinase
enzyme deficient in fructose intolerance
- aldolase B
enzyme deficient in classic galactosemia
- galactose-1-phosphate uridyltransferase
enzyme deficient in PKU
- phenylalanine hydroylase
enzyme deficient in alkaptonuria
- homogentisic acid oxidase
enzyme deficient in cystinuria
- defect of renal tubular amino acid transporter (COLA transporter)
cause of maple syrup urine disease
- blocked degradation of BCAA
cause of Hartnups
- defective neutral amino acid transporter
enzyme deficient in hyperchylomicronemia
- lipoprotein lipase deficiency or altered apo-CII
enzyme deficient in familial hypercholesterolemia
- absent or decreased LDL receptors
cause of hypertriglyceridemia
- hepatic overproduction of VLDL
mutation found in abetalipoproteinemia
- microsomal triglyceride transfer protein (MTP) gene which results in decreased B-48 and B-100
mutation associated with DM type I
CTLA4
mutation associated with DM type II
TCF7L2
mutation associated with IBD
IL-23
mutation associated with pituitary adenomas
GNAS1
mutation associated with autoimmune polyendocrinopathy
AIRE
