Detection of Chromosome Imbalance in Paediatric and Adult Referrals
Description:
Chromosomal microarray is a technique for genome-wide detection of chromosomal imbalance including triploidy. Testing is carried out using the ThermoFisher high-throughput chromosomal microarray (HT-CMA) microarray which has an expected median genome resolution of 74kb for losses and 125kb for gains for postnatal samples. SNP microarray can provide additional information and may also detect uniparental isodisomy, ploidy change and absence of heterozygosity (AOH). Absence of heterozygosity consistent with clinically significant Uniparental Disomy (UPD) will be reported however, AOH associated with shared parental heritage may not. Microarray cannot detect balanced chromosomal rearrangements.
The ThermoFisher HT-CMA SNP array has replaced our previous array platform which was the Agilent 60K custom comparative genome hybridisation array (array CGH).
The ThermoFisher HT-CMA SNP array has replaced our previous array platform which was the Agilent 60K custom comparative genome hybridisation array (array CGH).
Clinical details:
This test is applied as the initial approach for any patient suspected of having an unbalanced chromosome abnormality and is therefore suitable for investigating genetic causes of learning difficulties, dysmorphism and congenital physical abnormalities.
Common R codes:
• R377 Intellectual disability – microarray only
• R28 Congenital malformation and dysmorphism syndromes – microarray only
• R27 Congenital malformation and dysmorphism syndromes – microarray and sequencing
• R29 Intellectual disability – microarray, fragile X and sequencing
See the Genomic Test Directory for Rare and Inherited Disease for the full list of indications for testing https://www.england.nhs.uk/publication/national-genomic-test-directories/
Common R codes:
• R377 Intellectual disability – microarray only
• R28 Congenital malformation and dysmorphism syndromes – microarray only
• R27 Congenital malformation and dysmorphism syndromes – microarray and sequencing
• R29 Intellectual disability – microarray, fragile X and sequencing
See the Genomic Test Directory for Rare and Inherited Disease for the full list of indications for testing https://www.england.nhs.uk/publication/national-genomic-test-directories/
Synonyms or keywords:
Karyotyping, G-banded chromosome analysis, Chromosomes, microarray, array, SNP array, Chromosome, Duplication, Deletion, Trisomy, Monosomy, Karyotype.
Department:
Location:
Sample type and Volume required:
Peripheral blood in an EDTA bottle (5ml (2 - 3ml from babies)), DNA sample (2ug)
Turnaround time:
Urgent referrals 14 days. Non-urgent referrals 42 days weeks
Special sample instructions:
DNA extracted using Chelex/Instagene methods is not suitable for this test.
Storage and transport:
Samples should arrive within 72 hours.
Cost:
On application
Contacts:
For clinical advice or interpretation of results, please contact the laboratory in the first instance.
Laboratory:
Last updated: 26/10/2023
