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Definition
| region of a chromosome where the gene is located |
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Definition
| alternative form of a gene occupying the same locus on homologous chromosomes |
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Term
| mendelian genetics refers to |
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Definition
| single gene disorders - AD, AR, X-linked |
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Term
| marfan's presentation, inheritance, treatment |
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Definition
| long arms, arachnodactyly (long fingers), joint laxity, pectus carinatum (chest sticks out) or pectus excavatum, pes planus (flat feet), scoliosis, arm span-to-height ratio>1.05, upper-to-lower segment ratio<.85, wrist/thumb signs, ectopia lentis, high myopia, retinal detachment, mitral valve prolapse, aortic root dilatation/dissection. family history of early sudden death. AD but can be de novo. 45 death for men, 54 death for women but normal life expectancy with treatment - losartan. |
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Term
| AD / what do they usually do (2) |
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Definition
| affected heterozygote has 50% chance of having affected offspring. multigenerational, equal sex affected. / usually affect structural proteins with a gain of function OR cause haploinsufficiency of a protein or enzyme |
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Term
| neurofibromatosis type 1 presentation, inheritance, treatment |
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Definition
| multiple cafe-au-lait spots, often idiopathic hypertension, variable expressivity, age-related (but not variable) penetrance. AD but can be de novo (50%). treatment = rapamycin, treat hypertension. |
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Definition
| you may or may not get the disease if you have the disease gene. BRCA = breast cancer gene |
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Definition
| you definitely get the disease if you have the gene, but it might affect you in different ways than it affects other people |
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Definition
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Definition
| looks like NF1 but without tumors. molecular testing costs $3000 and a negative test does not rule out NF1. (if have neither gene, check for missing exons in deletion/duplication testing) |
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Definition
| we don't know why it's happening (we're idiots) |
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Definition
| vomiting, headache, fatigue, rhizomelic shortening of limbs and short stature, big head, trident configuration of hands (can't pull thumb all the way in). may have narrowing of foramen magnum, which can compress the brainstem. complete penetrance, AD (gain of function = too much inhibition of chondrocytes) but 80% are de novo. if these women have babies they need C-sections. treatment = CNP (C-type natriuretic peptide), surgery to fix foramen magnum. |
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Term
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Definition
| upper limb segment shortening |
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Definition
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Definition
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Definition
| lower limb segment shortening |
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Term
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Definition
| de novo mutation in multiple oocytes or sperm but not in parent; NOT a term used for AR disorders, only AD and x-linked. |
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Term
| osteogenesis imperfecta types I through IV |
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Definition
| I: classical: bone fragility, blue sclerae, otosclerosis. II: (often germline mosaicism) usually lethal bone fragility. III: severe to lethal, wheelchair bound and short. IV: often milder - like classical but with white sclerae |
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Term
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Definition
| AD except in rare cases of AR type III. locus hetergeneity on type 1 collagen producing genes. in most cases is diagnosed clinically, but biochemical or molecular diagnosis can be used. biochemical is much better (skin biopsy only, no ambiguity). treatment = bisphosphonates like IV pamidronate |
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Definition
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Definition
| in some AD disorders, like OI type II, the reproductive fitness is zero. thus all are either new mutations or germline mutations. |
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Term
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Definition
| seen in some AD disorders including achondroplasia |
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Term
| AR / what do they usually do |
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Definition
| both parents are unaffected heteros w. 1/4 chance of affected offspring. unaffected offspring have 2/3 chance of being carriers. homo normal x homo affected = all hetero. an affected homo can have two different mutant alleles = compound heterozygote. consanguinity is a clue. equal sex. disorder rarely present in parents. founder effect. / usually cause enzyme abnormalities, with enzyme levels in heteros at 50% |
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Term
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Definition
| an affected AR homozygote can have two different mutant alleles |
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Definition
| high prevalence of disorder due to members of population from shared ancestor who harbored disease causing mutation. happens often in AR mutations. (ethnic group clusters, relative geographic or religious isolation) |
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Term
| urea cycle disorder: presentation, inheritance, treatment |
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Definition
| seizures, coma, cerebral edema, high ammonia and citrulline levels, intellectual disability or death if not treated. AR. remove accumulating toxic metabolites = treatment. |
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Term
| carrier testing for tay sachs, CF, sickle cell, PKU |
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Definition
| enzyme analysis, DNA mutation analysis, electrophoresis, Restriction Fragment Legth Polymorphisms |
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Term
| pre-implantation diagnosis |
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Definition
| expensive + side effects. parents may also consider amniocentesis. |
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Term
| mucopolysaccharidoses: presentation, inheritance, treatment |
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Definition
| failure to thrive (slow growth and development), coarse facial features, asthma, dysostosis multiplex bones, progressive symptoms in all internal organs from storage of GAGs; death may occur in childhood or early adulthood. AR. treatment: naglazyme. |
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Term
| mucopolysaccharidose types I-VI |
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Definition
| I: H&S (Hurler), II: Hunter (hunters can't see - x-linked coronial clouding in men), III: ABCD Sanfilippo, IV: Morquio, V: Maroteaux Lamy, VI: Sly |
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Definition
| parents of AR mutants are considered obligate carriers |
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Definition
| (AR) in sickle cell anemia, carriers have protection against malaria |
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Term
| duchenne muscular dystrophy presentation, inheritance, treatment |
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Definition
| presents at age 3-6, difficulty walking, frequent falling, difficulty getting up from a sitting or lying position. at age 12 = unable to walk, usually fatal in teens or early 20s due to ventricular hypertrophy = respiratory/heart problems. X-linked. 1/3 new mutations. 60% hetero deletions, 10% duplications, 30% point mutations. has germline mosaicism effects. prenatal diagnosis and carrier testing are available through PCR (deletions) and linkage analysis (point mutations). treatment: exon-skpping by antisense oligonucleotides to rescue dystrophin protein synthesis. |
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Term
| affected male gets x-linked disorder how |
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Definition
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Term
| affected female gets x-linked disorder how |
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Definition
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Term
| if a male can/can't survive an x-linked disorder... |
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Definition
| can: = x-linked (old term = x-linked recessive), can't = x-linked commonly lethal in males (old term = x-linked dominant). |
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Term
| [[know x-linked punnett square]] x-linked pedigree? |
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Definition
| affected males (squares). trait is passed from affected males to all daughters. |
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Term
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Definition
| x-linked commonly lethal in males disorder. female carriers have symptoms (dominant!) and have 50% chance of passing to either a son or a daughter. |
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Term
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Definition
| dots = x-linked carrier, half-moons = AR carrier |
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Term
| lyon hypothesis / in rare cases |
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Definition
| x-chromosome inactivation. random! tortoiseshell cats. / in rare cases preferential x-inactivation happens: 90% = unaffected X! |
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Term
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Definition
| once x inactivation takes place, all descendants of that cell inactivate the same x |
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Term
| variation in XLR disorders in females (possibilities) |
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Definition
| could be homozygous for mutant allele; cells with normal x inactivated could be present in disproportionate numbers; affected female could have turner's syndrome; mutated epistatic gene could be involved; disorder could exhibit autosomal recessive/x-linked locus heterogeneity |
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Term
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Definition
| other gene at another location which affects the level of activity of the original gene product from a normal allele |
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Term
| becker muscular dystrophy |
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Definition
| less intense than duchenne (no dilated cardiomyopathy), but still with left ventricular dilation. high liver function. has germline mosaicism effects. |
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Term
| favorably/unfavorably skewed x-cell inactivation |
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Definition
| favorably = preferential, unfavorable = x-linked carrier females with extra symptoms |
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Term
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Definition
| females with x-linked recessive disorders who are probably unfavorably skewed |
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| study flash review and practice questions in binder! |
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Definition
| do i need to know that mitochondrial disease article? e-mail luba |
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