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14 Cards in this Set
- Front
- Back
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Gene for marfan
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Fibrillin
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Gene for OI
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collagen
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Locus heterogeneity
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Mutations @ diff loci but still produce the same phenotype Ex: OI - chrom 17 (colA1 gene), or chrom 7 (colA2 gene) |
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Auto Rec & Locus Hetero in Congen Deafness
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Scenario: Couple A = AaBB (a = mutant allele) --> through auto rec recurrence, 50% are affected (homos) Couple B - AABb (b = mutant allele) --> through auto rec recurrence, 50% are affected (homos) One affected from couple A (aaBB), and one affected from couple B (AAbb) get married.
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Compound Heterozygote
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Showing phenotype bc you inherited mutant gene from both parents Even though mutant gene are different alleles for each parent |
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Germline mosacism
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also called GONADAL mosacism mutation is present in proportion of germline cells Presence of 2 affected kids = germline mosacism |
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mitochondrial inheritance
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all offspring of affected female = AFFECTED
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variable expression in mito disorders
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heteroplasmy -- depends on number of mito w mutant gene
mito dna segregates passively during division --> unequal distribution of mutant/non-mutant mito dna leads to heteroplasmy and variable expression |
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List of mito diseases
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1. Leber hereditary optic neuropathy = progressive blindness around 20-30 yrs 2. MELAS = mito enceph, lactic acidosis, Stroke-like episodes 3. MERRF = myoclonic epilepsy w ragged red fibers (muscle) |
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Disorders w non-Mendelian/Unexpected Inheritance Patterns
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1. Digenic disorders = retinitis pigmentosa 2. imprinting = prader willi and angelman syndromes (both are parent of origin effect) 3. triplet repeat disorders = huntington (autodom), myotonic (autodom) and fragile x (x-linked) |
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Digenic disorders
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mutations in 2 genes = additive and required to produce disorder Think of retinitis pigmentosa = mutations in 2 independent loci (ROM1 & peripherin) - both need to be deleted in order for the disease to occur |
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Imprinting (parent of origin effects)
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some genes only active when transmitted --> methylation of specific loci (epigenetic change) & silencing the gene
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Prader Willi Syndrome
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- caused by a) microdeletion of paternal chromosome 15 (70% of thetime), or by maternal uniparental disomy of chrom 15 - Mental/developmental delays - Underdeveloped genitals |
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Anticipation
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Earlier age w each generation of pedigree --> the greater the # of repeats, the earlier the age of onset and the more severe --> huntington is more severe if from father |
