Multi locus imprinting disorder (Mlid)

There are around 12 currently known imprinting disorders caused by abnormalities (sequence variants, CNVs, UPD or methylation defects) at imprinted regions on chromosomes 6q24, 7p12, 7q32, 11p15, 14q32, 15q11 and 20q13. A subset of patients with imprinting disorders have been found to have abnormal methylation at more than one locus, a condition termed Multi Locus Imprinting Disorder (MLID). Patients with MLID may have different or additional clinical features to those with an imprinting defect at a single locus. MLID is most common in Transient Neonatal Diabetes Mellitus caused by hypomethylation at PLAGL1:alt-TSS-DMR (6q24), Beckwith-Wiedemann syndrome caused by hypomethylation at KCNQ1OT1:TSS-DMR (ICR2; 11p15), Silver-Russell syndrome caused by hypomethylation at H19-IGF2:IG-DMR (ICR1; 11p15) and Pseudohypoparathyroidism type IB caused by methylation anomalies of the GNAS complex locus DMRs (20q13).

NHSE test directory code: R417 Multi locus imprinting disorder.

Methylation analysis of 6q24, 7p12, 7q32, 11p15, 14q32, 15q11 and 20q13 by MS-MLPA.

Visit the NHS Genomic Test Directory 

Eligibility criteria for genomic tests can be found in the National Genomic Test Directory.

This lists the clinical specialties that would be expected to request for a given clinical indication and sets out which patients should be considered for testing.

All samples for genomic testing should be accompanied by a fully completed request form.

The request form should include as much clinical information about the patient or family member, family relationships and the requested test code (R number). All request forms must indicate either a specific disorder/gene(s) to be investigated or, a request to extract and store DNA.

This form should be used for the majority of test requests.

Please do not download and store this on your desktop or system. The form is regularly updated. Our recommendation is to save or bookmark a link to our website to ensure you are working with the most up-do-date version.

Download the latest version here: GMS Test Order Form v2.3

An appropriate discussion of genomic testing and the possible implications for a patient and their family members must take place before testing is requested.

It is the referring clinician’s responsibility to ensure that the patient/carer knows the purpose of the test and that the sample may be stored for future diagnostic testing. In submitting a sample with a request form, the clinician confirms that informed consent has been obtained for (a) testing and storage (indefinitely) (b) the use of this sample and the information generated from it to be shared with members of the donor’s family and their health professionals (if appropriate). The patient should be advised that the samples may be used anonymously for quality assurance and training purposes.

If stated as a requirement for a specific test, a record of this discussion must be retained within the patient record when a genomic test is ordered.

For more information please view the Consent and Confidentiality in Genomic Medicine guidelines from the Joint Committee on Medical Genetics.

Before sending samples for genomic testing, please ensure you follow the correct preparation and transport guidelines. This includes information on sample types, volumes, handling, labelling, and packaging standards.

For a full list of sample requirements and transport guidance, please visit the samples and transport page of the website. 

Turnaround times (TATs) for genomic tests are continually refined through ongoing reviews of testing standards.

Results will be returned to the email account or clinician listed on the request form.

Visit the results and turnaround page for more information.