Prenatal Diagnosis for Ultrasound Abnormality

Description: 
Following exclusion of trisomies 13, 18 and 21, samples are tested using prenatal array CGH. Prenatal arrays are targeted to detect imbalances ≥0.4Mb, and those associated with the following microdeletion/microduplication syndrome regions:

1p36 microdeletion syndrome (OMIM 607872)
Brachydactyly-mental retardation syndrome (2q37 deletion syndrome; OMIM 600430)
3q29 deletion syndrome (OMIM 609425)
3q29 duplication syndrome (OMIM 611936)
Wolf-Hirschhorn syndrome (OMIM 194190)
Cri du Chat syndrome (5p deletion syndrome; OMIM 123450)
Sotos syndrome (OMIM 117550)
Williams-Beuren region duplication syndrome (7q11.23 duplication syndrome; OMIM 609757)
Williams-Beuren syndrome (OMIM 194050)
8p23.1 deletion syndrome
Kleefstra syndrome (9q34.3 / 9p subtelomere deletion syndrome; OMIM 610253)
Wilms tumour, aniridia, genitourinary abnomalies and mental retardation syndrome (WAGR / 11p13 deletion syndrome; OMIM 194072)
Potocki-Shaffer syndrome (11p11.2 deletion syndrome; OMIM 601224)
Angelman syndrome (OMIM 105830)
Prader-Willi syndrome (OMIM 176270)
15q24 deletion syndrome (OMIM 613406)
15q24 duplication syndrome (OMIM 613406)
Rubinstein-Taybi syndrome (OMIM 610543)
16p11.2 deletion syndrome, distal (OMIM 613444)
Miller-Dieker lissencephaly syndrome (OMIM 247200)
Charcot-Marie-Tooth syndrome type 1A (CMT1A; OMIM 118220)
Hereditary Liability to Pressure Palsies (HNPP; OMIM 162500)
Potocki-Lupski syndrome (17p11.2 duplication syndrome; OMIM 610883)
Smith-Magenis syndrome (OMIM 182290)
17q11.2 deletion syndrome (NF1-microdeletion syndrome; OMIM 613675)
17q21.31 deletion syndrome (OMIM 610443)
Cat-Eye syndrome (OMIM 115470)
DiGeorge syndrome (22q11.2 deletion syndrome; OMIM 188400)
22q11.2 duplication syndrome (OMIM 608363)
Velocardiofacial (22q11.2 deletion syndrome; OMIM 192430)
Pelizaeus-Merzbacher disease (OMIM 312080)
Rett syndrome (MECP2; OMIM 312750)
Ichthyosis X-linked (OMIM 308100)
Clinical details: 
All prenatal samples referred to our laboratory are tested using QF-PCR as a first test. Additional testing with prenatal array CGH is offered because scientific evidence shows that these groups of women are at increased risk for other chromosomal rearrangements in addition to the major trisomies. The following groups of women will be suitable for dual testing with QF-PCR and prenatal array CGH:

*Ultrasound detection of any major structural abnormality including nuchal translucency of 3.5mm or greater before 14 weeks gestation, or a nuchal fold measuring 6mm or greater between 14 and 20 weeks gestation.
*Ultrasound detection of two or more minor markers of aneuploidy. Consistent with NSC guidelines, karyotyping should not be offered for a single marker (with the exception of a nuchal fold of >3.5mm before 14 weeks gestation, or >6mm before 20 weeks gestation) in women who have already been given a low risk following DS screening.
*Previous pregnancy indicating a possible increased risk of recurrence of chromosomal imbalance, other than the major trisomies.
Synonyms or keywords: 
Rapid aneuploidy detection, Prenatal array CGH, Prenatal karyotyping. Prenatal testing, CVS, AF, array CGH, aCGH.
Department: 
Sample type and Volume required: 
DNA sample (1μg), amniotic fluid in a dry sterile container (20ml), CVS (20mg please discuss with the laboratory)
Call in advance: 
Please notify the laboratory before sending prenatal samples by e-mailing gst-tr.viapathgeneticsadmin@nhs.net
Turnaround time: 
1 - 3 working days for QF-PCR, 10-14 days for prenatal array CGH
Special sample instructions: 

Patient information and consent:

Please ensure patient consent is obtained prior to the sample being sent to the laboratory for prenatal array CGH (please note patient consent forms should be stored and should NOT be sent to the laboratory).

The patient prenatal array information leaflet and consent form can be found above.

Referral information required:

Referral form and ultrasound report (please note an ultrasound report is MANDATORY for samples requiring prenatal array CGH)

Storage and transport: 
All prenatal samples must arrive in the laboratory on the day of sampling, preferably before 3pm.
Time limit for extra tests: 
Do not spin down or freeze samples before sending.
Contacts:
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 12/09/2017