Principles of Clinical Cytogenetics and Genome Analysis

Flashcards on Clinical Cytogenetics and Genome Analysis

Clinical Cytogenetics

The study of chromosomes, their structure, and their inheritance, as applied to the practice of medicine.

Chromosome Disorders

Clinical conditions resulting from microscopically visible changes in the number or structure of chromosomes (chromosome abnormalities).

Giemsa banding (G banding)

A staining procedure developed in the early 1970s that is the gold standard for detecting and characterizing structural and numerical genomic abnormalities in clinical diagnostic settings.

Metacentric Chromosomes

Chromosomes with a more or less central centromere and arms of approximately equal length.

Submetacentric Chromosomes

Chromosomes with an off-center centromere and arms of clearly different lengths.

Acrocentric Chromosomes

Chromosomes with the centromere near one end, found in humans as chromosomes 13, 14, 15, 21, and 22.

Fragile Sites

Nonstaining gaps occasionally observed at particular sites on several chromosomes that are prone to regional genomic instability.

High-Resolution Banding

A chromosome analysis technique achieved by staining chromosomes obtained at an early stage of mitosis (prophase or prometaphase), also called prometaphase banding.

Fluorescence In Situ Hybridization (FISH)

A method for detecting the presence or absence of a particular DNA sequence or for evaluating the number or organization of a chromosome or chromosomal region in situ (literally, “in place”) in the cell.

Chromosomal Microarray

Techniques that simultaneously query the whole genome represented as an ordered array of genomic segments on a microscope slide.

Comparative Genome Hybridization (CGH)

Detects relative copy number gains and losses in a genome-wide manner by hybridizing two samples—one a control genome and one from a patient—to microarrays.

Single Nucleotide Polymorphism (SNP) Arrays

Arrays that contain versions of sequences corresponding to the two alleles of various SNPs around the genome.

Aneuploidy

An abnormal chromosome number due to an extra or missing chromosome.