Gen4-Clinical Genetics

Front 1

How are chrom clasified?

Back 1

Size (largest to smallest), Centromere position (Meta=middle, Submeta=off center to short arm, & banding pattern (Giemsa-from center out)

Front 2

What are the conventional cytogenetic methods?

Back 2

Giemsa banding & High resolution G-banding

Front 3

What are the molec cytogen tech?

Back 3

Fluorescence In Situ Hybridization (FISH-interphase or metaphase. Finds micro deletions & duplic), Multicolor Spectral Karyotyping (SKY-complex rearrangements, better resolution, array comparable to Compar Genomic Hybrid aCGH

Front 4

What are the types of probes used in FISH?

Back 4

Locus-specific (detect presence or absence of gene; microdel), Satellite DNA probes (for centromeres; determines aneuploidy in interphase), Chromosome paints (spectral karyotyping)

Front 5

What congenital defects can be identified via FISH?

Back 5

Prader-Willi/Angelman, Digeorge/velocaridofacial syn, Smith-Magenis syn, & Wiliams syn

Front 6

What is the best method for detecting copy # imbalances?

Back 6

Array CGH

Front 7

What is CGH array?

Back 7

Cloned DNA seg are substituted for meta chrom as targets for hybridization. Like FISH. Doesn't ID balanced rearrangements

Front 8

What are the conseq of unbalanced chrom complement?

Back 8

Autosomal aberrations results in congenital & mental defects (eg trisomies, partial trisomies, & microdel). Sex aberrations ass w/ infertility & abnormal sex maturation (eg Turner's & Klinfelter's)

Front 9

What are the 2 types of Chrom aberrations?

Back 9

Numerical & Structural

Front 10

What are the types of structural aberrations?

Back 10

Translocations (reciprocal balanced-t, unbalanced translocations-der, Robertsonian translocation-rob), Deletions-del (terminal & intersitial), Inversions-inv (pericentric involves centromere or paracentric doesn't involve centromere), & Insertions-ins (direct or inverted)

Front 11

What are the charac of trisomy 18?

Back 11

Clinched fists (2 & 5 dgits overlap the 3rd & 4th), rocker bottom feet, mental retardation, failure to thrive, 80% female & 20% involve translocation of all or part of chrom 18

Front 12

What are the charac of trisomy 13?

Back 12

Holoprosencephaly, congenital heart disease, microcephaly, polydactyly, cleft lip/palate, about 1/2 die w/I the 1st mth

Front 13

What is Cri du Chat Syndrome?

Back 13

Deletion of the short arm of chrom 5, mewing cat cry, 1% of institutionalized mentally retarded, microcephaly,hypertelorism, moon like facies,10-15%are offspring of tranlocation carriers

Front 14

What are the charac of Turner's syndrome?

Back 14

45,X is the most common.X is of maternal orgin 70% of time. Short, webbed neck, gonadal dysgenesis

Front 15

What are the charac of Klinefelter's syndrome?

Back 15

47,XXY. 50% result from errors in paternal meiosis I. Tall, thin limbs, hypgonadism, infertility

Front 16

What causes chromatin diseases?

Back 16

Mutations in genes encoding proteins that control the stucture of chromatin. Could potentially affect a large # of genes

Front 17

Wha tis an example of a chromatin disease? Charac?

Back 17

ICF (Immunodefic, Centromeric instability, & Facial anomalies). Mendelian disorder w/ cytogenetic affects, AR inheritance (biallelic mutations to DNMT3B). Pericentric heterochromatin & multiradials of chrom 1q

Front 18

What are the clinical features of ICF?

Back 18

Immunodeficiencies, facial anomalies, developmental delay, mental retardation

Front 19

What are the common ass of Anirida-Wilms' Tumor Syndrome?

Back 19

Mental retardation, microcephaly, bilat aniridia, Wilms' tumor, ambiguous genitalia in males, usually sporadic, deletion 11p13