Diagnosis of Cryptic Chromosomal Syndromes by Fluorescence In Situ Hybridization (FISH)

Abstract

This unit describes the various methods by which cytogeneticists detect chromosome abnormalities. The unit offers guidance for detecting such abnormalities with fluorescence in situ hybridization (FISH), as well as the benefits, limitations, and other applications of FISH.

Molecular Cytogenetic Analysis of Telomere Rearrangements

“…Similar observations became more widespread with the advent of fluorescence in situ hybridization (FISH; see UNITS & ; Knoll and Lichter, , and Kashork et al., , respectively) in the study of other telomeric microdeletion syndromes. For example, in the authors’ investigations of the Miller‐Dieker lissencephaly syndrome (MDS), submicroscopic deletions (<3 Mb) in 17p13 were initially detected by Southern blot analysis ( UNIT ; Jarcho, ) using VNTR polymorphisms.…”

“…Since that time, screening for telomere abnormalities on a clinical basis has escalated with the availability of multiplex commercial assays using Fluorescence In Situ Hybridization (FISH; see UNIT 8.10;Kashork et al, 2010), and other DNA-based approaches, such as Multiplex Ligation-dependent Probe Amplification (MLPA), based on identification of a set of human telomere clones representing the most distal unique DNA region for every…”

“…Since that time, screening for telomere abnormalities on a clinical basis escalated with the availability of multiplex commercial assays using Fluorescence In Situ Hybridization (FISH; see UNIT 8.10;Kashork et al, 2010), and other DNA-based approaches, such as Multiplex Ligation-dependent Probe Amplification (MLPA), based on identification of a set of human telomere clones representing the most distal unique DNA region for every chromosome (Knight et al, 2000). Biesecker (2002) reviewed the early literature on telomere screening (14 studies including close to 2000 individuals) and estimated a rate of telomere abnormalities in ß6% of individuals with idiopathic ID and a normal karyotype, consistent with the initial studies.…”

“…In fact, only two studies were published, which estimated the frequency of telomere abnormalities in idiopathic intellectual disability (ID). These studies estimated a frequency of telomere abnormalities in 5% to 6% 7.4% (Knight et al, 1999) of individuals with ID, respectively.Since that time, screening for telomere abnormalities on a clinical basis has escalated with the availability of multiplex commercial assays using Fluorescence In Situ Hybridization (FISH; see UNIT 8.10;Kashork et al, 2010), and other DNA-based approaches, such as Multiplex Ligation-dependent Probe Amplification (MLPA), based on identification of a set of human telomere clones representing the most distal unique DNA region for every…”

Genomic Microarray Quality Assurance

“…Methods for confirmation of array results may include fluorescence in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), quantitative PCR (Q-PCR) and other PCR techniques. FISH is an established technique that is used to identify numerical and structural chromosome abnormalities by using fluorescently labeled DNA probes to detect the presence or absence of the DNA in the interphase nucleus or in metaphase, the stage of active cell division when the chromosomes are visibly condensed and can be observed in a microscope (Kashork et al, 2010). FISH commonly uses unique-sequence BAC probes; depending on the specific probe used, the resolution of metaphase FISH is ~80-200 kb (Shaffer et al, 2001).…”