Developmental Disorders (DD)

Frontline testing for children with learning disabilities, dysmorphic features and congenital anomalies, collectively termed developmental disorders (DD) is performed by Chromosomal Microarray Analysis (CMA).  CMA replaces standard routine karyotyping for these patients due to its increased resolution above that of chromosome analysis, with an anomaly detection rate 10 -20% greater than karyotype analysis in children with unexplained learning disability.

The CMA platforms used within WMRGL comply with the International Standards for Cytogenomic Arrays (ISCA) design criteria. More information on the ISCA project is available at

Quantitative Fluorescent PCR

Quantitative fluorescent PCR (QFPCR) is currently used to screen neonates referred with a suspected trisomy (chromosomes 13, 18 or 21) or ambiguous genitalia for sex confirmation.  This rapid testing will only provide targeted information and can usually provide a result within 48-72 hours. Many of these patients then go on to have CMA performed unless otherwise advised by the referring clinician.

Single gene tests

Some children with developmental disorders require a more specific single gene test such as those for Prader-Willi, Angelman, Rett and Fragile X Syndromes. These referrals usually have a more specific range of clinical features and testing is carried out based on current UKGTN guidelines.

These single gene disorders are usually only tested for once CMA has been performed and a negative result obtained, unless there is a proven positive family history.


For sample requirements and reporting times please see the test directory.

  • Blood samples for all test types should be sent in both EDTA and Lithium Heparin (1- 5ml in each).