Downsyndrome.com

Health/Medical Writers

SAN FRANCISCO–(BUSINESS WIRE)–July 30, 2003

California Pacific Medical Center is one of the first hospitals in the country to offer pregnant women Integrated Screening for Down syndrome.

Integrated Screening is a new, comprehensive test for Down syndrome which detects up to 90% of cases, compared to current tests which offer a 60% detection rate for Down syndrome.

The screening is being offered as part of a pilot program which teams CPMC’s Prenatal Diagnosis Center with the Division of Prenatal and Special Testing at Women & Infants Hospital in Providence, Rhode Island.

The screening is performed in two stages during the first and second trimesters:

        Stage One (performed between 11 1/2 and 14 weeks of
        pregnancy):

            --  high-resolution ultrasound measurement of the fetal
                neck area, and
            --  blood sample taken to measure the amount of
                pregnancy-associated plasma protein-A (PAPP-A).

        Stage Two (performed at 15-16 weeks, but no later than 20
        weeks of pregnancy):

            --  Second blood sample taken to measure the amount of
                three biochemicals in the blood: alpha-fetoprotein
                (AFP), human chorionic gonadotropin (hCG), and
                unconjugated estriol (uE3).
            --  Results from both steps are combined to give a single
                screening result.

The ultrasound measurement and the levels of the four maternal serum markers are used — along with age — to estimate the patient’s risk of having a baby with Down syndrome.

"We are very excited about this new approach for Down syndrome screening," says Dr. James D. Goldberg, Co-Director of the Prenatal Diagnosis Center at California Medical Center. "In addition to increasing the Down syndrome detection rate compared to current testing, the test false-positive rate is significantly reduced, which substantially improves safety by reducing the number of women who need an amniocentesis."

Because this is a pilot program not fully covered by insurance, patients are asked to pay a $50 participation fee. In the majority of cases, insurance pays other costs associated with Integrated Screening, including the first trimester ultrasound, second trimester expanded AFP screening, and consultation with a genetic counselor.

About Prenatal Diagnosis Center

The Prenatal Diagnosis Center at California Pacific Medical Center is the largest prenatal diagnosis center in California. It offers the full range of prenatal diagnostic services including, genetic counseling, high resolution ultrasound, nuchal translucency screening, chorionic villus sampling, amniocentesis, and fetal therapy.

About California Pacific Medical Center

California Pacific Medical Center, a Sutter Health affiliate, is one of the largest private, not-for-profit teaching medical centers in Northern California. We are a tertiary referral center providing access to leading-edge medicine while delivering the best possible personalized care. CPMC provides a wide variety of services, including, acute, post-acute and outpatient hospital care; home care and hospice services; preventive and complementary care; and health education. Through our Medical Education Program and our Research Institute, physicians at California Pacific Medical Center are able to bring health care innovation to the bedside.

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COPYRIGHT 2008 Gale, Cengage Learning

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It is well-established that folic acid supplementation during pregnancy is associated with a significantly lower risk of having a child with a neural-tube defect (NTD; e.g., spina bifida, anencephaly). However, a recent study in The Lancet (2003; 361 [9366]:1331-5) provides evidence that folic acid supplementation also is associated with reduced risk of Down’s syndrome. Researchers compared medical data from approximately 490 families at high risk for NTD with data from 516 families at high risk for Down’s syndrome, and discovered that Down’s syndrome was much more prevalent in pregnancies involving families at high risk for NTD. The evidence suggests that mothers of children with Down’s syndrome experience an abnormal metabolism of folate and methyl, as well as mutations in their folate gene. These traits are also seen in infants affected by NTD.

Folate (folic acid, a B vitamin) is unique in that it contains a methyl group (CH^sub 3^), which it donates to homocysteine to permit its enzymatic conversion to methionine. Once formed within the cells of the body, methionine (a methyl-containing amino acid) extracts the adenosine ring from adenosine triphosphate (ATP) and becomes S-adenosyl methionine (SAMe). SAMe is then able to donate its methyl group (originally derived from folate) to many biochemical reactions, ineluding the synthesis of DNA bases. Consequently, DNA synthesis requires a constant, adequate supply of folate on a daily basis.

During pregnancy, the rapid rate of fetal cell division demands an even greater supply of folic acid; if the demand is not met, DNA defects occur, which most often manifest as neural-tube defects. Evidence from the Lancet study suggests the same may be true for Down’s syndrome. To complicate matters, some individuals have an inborn error of folate or methyl metabolism, in that they show a defect in the enzyme that converts homocysteine to methionine, and thus produce insufficient amounts of SAMe. However, studies show that these individuals can improve the conversion of homocysteine to methionine significantly if they are provided with higher supplementation levels of folic acid (which is the coenzyme for this reaction) in many cases. Therefore, mothers identified as high-risk for NTD usually express this type of folate or methyl defect and are prescribed higher supplemental levels of folic acid. The Lancet study provides evidence that these women are also at higher risk for delivering a child with Down’s syndrome, indicating that higher folic-acid supplementation may be of great importance in reducing the risk of NTD and Down’s syndrome.

The researchers conclude that because of the links in the development of the two complications, folate supplementation before conception has the potential to reduce NTD and Down’s syndrome during pregnancy. Most women would benefit from 400 meg of folic acid prior to conception (most multiple vitamins contain this amount) and 800 meg during pregnancy (the amount contained in prenatal vitamins). Women with folate or methyl metabolism problems require additional amounts of supplemental folic acid, which should be prescribed by their attending physicians or specialists, who can best monitor the appropriate biomarkers.

Reference

NNFA Supplement (April 28, 2003).

James Meschino, DC, MS. Dr. Meschino’s articles, a “Talk Back” forum and a brief biography of the author are available online at www.chiroweb.com/columnist/meschino.

Copyright Dynamic Chiropractic Jul 14, 2003
Provided by ProQuest Information and Learning Company. All rights Reserved

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