» Diagnosis

Blood test hope for anxious CdLS parents

Two British laboratories are now able to offer a simple blood test that should signal an increased or decreased risk of CdLS during pregnancy offering tremendous relief to anxious parents of CdLS children who want another child and to siblings of people affected by CdLS.

The test is called a PAPP-A (Pregnancy Associated Plasma Protein-A) and its significance to CdLS was discovered after tests on the samples of a number of mothers who subsequently had CdLS babies.

Dr Laird Jackson, chairman of the Foundation’s Scientific Advisory Comunicla has appealed to the parents of CdLS infants less than six months old to help us confirm the test. They can do this by simply asking their obstetrician to request the test before the samples are denied.

The PAPP-A test can be run on a mother’s blood serum taken at various stages of her pregnancy although it is not a test that is done routinely.

It is currently used in Britain as an indicator for risk of Down’s Syndrome and the test is taken between an expectant mother’s 9th and 13th week of pregnancy.

Detailed analysis

Following some detailed analysis of a sample taken from the mother of a confirmed CdLS child who had seen Dr Jackson at a Foundation meeting, it was proved that a blood sample taken later in the pregnancy – between 16 and 18 weeks will give an indication of a risk of a CdLS child.

The two British clinics that are able to do this test – Harold Wood Hospital in Essex and Leeds University in West Yorkshire – have both said they would provide the analysis and report back to the mother’s doctors as appropriate.

Dr Jackson said: “It is important to understand that these tests, whether for risk of CdLS or risk of Down’s Syndrome, are tests for increase or decrease of RISK and are not diagnostic tests.

“If they suggest increase of risk then they must be followed by some more definitive test – for CdLS this means the stringent and targeted analysis of ultrasound features of the foetus that might enable one to confirm or deny the diagnosis.

For families with anxiety over succeeding pregnancies where there is already a child with CdLS in the family this could be very helpful.”

Dr Jackson is recommending the test be requested – it is not automatic – by any family with an existing CdLS person in it.

Sensitivity

If any parents of infants are able to ask their doctors to have their earlier samples retested it would help others. “The samples can be retrieved and assayed. Additional assays to correlate with CdLS foetuses will help extend our accuracy and sensitivity of testing,” Laird said.

The two clinics where the PAPP-A tests are done are:

Endocrine Unit, Clinical Biochemistry Department, Harold Wood Hospital, Gubbins Lane, Romford Essex, RM3 0BE (attn Kevin Spencer).

Leeds Antenatal Screening Service; Centre for Reproduction Growth & Development, University of Leeds, 26 Clarendon Road, Leeds LS2 9NZ (phone 0113-234-4013, attn Dr Howard Cuckle).

All samples should request the BIOMARK test with added PAPP-A at no charge.
 
Reaching Out newsletter
April 2001