Quality assessment of routine nuchal translucency measurements: a North American laboratory perspective.

PURPOSE: To assess nuchal translucency measurements that were performed as part of routine prenatal screening for Down syndrome. METHODS: Collect ultrasound measurements of nuchal translucency and crown rump length provided by individual sonographers over a 6-month period to six North American prenatal screening laboratories, along with the laboratory's nuchal translucency interpretation in multiples of the median. For sonographers with 50 or more observations, compute three nuchal translucency quality measures (medians, standard deviations, and slopes), based on epidemiological monitoring. RESULTS: Altogether, 23,462 nuchal translucency measurements were submitted by 850 sonographers. Among the 140 sonographers (16%) who submitted more than 50 observations, 76 (54%) were found to have all three quality measures in the target range. These 140 sonographers collectively accounted for 14,210 nuchal translucency measurements (61%). The most common single measure to be out of range was nuchal translucency multiples of the median, found for 29 of the 140 sonographers (21%). CONCLUSION: Laboratories should routinely monitor the quality of nuchal translucency measurements that are received for incorporation into Down syndrome screening risk calculations and interpretations. When possible, instituting sonographer-specific medians and providing individualized feedback about performance and numbers of women tested offer the potential to yield more consistent and improved performance.

Comprehensive analysis of genetic polymorphisms in the interleukin-10 promoter: implications for immune regulation in specific ethnic populations.

The association of interleukin-10 (IL-10) promoter single-nucleotide polymorphisms (SNPs) as risk factors for certain inflammatory diseases, viral infections, cancers, and transplant rejection have been the subject of recent studies. The SNPs -1082 G --> A, -819 C --> T, and -592 C --> A, which have been associated with differential IL-10 production, are strongly linked with ethnicity. In this study, we determined the ethnic distribution of IL-10 promoter SNPs and their haplotype rates among Hispanics, African Americans, and Caucasians from Texas and Ashkenazi Jews from New York. Significant differences in prevalence rates of IL-10 SNPs (and their haplotype distribution) were found. African Americans and Hispanics have a lower rate of putative high-producer SNPs and a higher rate of low IL-10 producers when compared to Caucasians or Ashkenazi Jews. No statistically significant differences in allelic frequencies and haplotype rates were observed between Caucasians and Ashkenazi Jews. This study provides critical new information on the ethnic distribution of IL-10 promoter SNPs in a regional U. S. population and is the first to analyze the rate of SNPs in an unstudied ethnic population, Ashkenazi Jews. Knowledge of IL-10 promoter polymorphisms may prove useful in prediction of immunization responses, disease severity, and in the intelligent design of customized immunotherapy.

Prenatal screening for open neural tube defects.

The era of prenatal screening for serious birth defects began in the 1970s with the discovery that amniotic fluid and maternal serum levels of alpha-fetoprotein (AFP) were increased in pregnancies affected by fetal open neural tube defects. Since then, prenatal screening has become a part of routine obstetric care. In this article, the use of AFP in prenatal screening for open neural tube defects is discussed in the context of the laboratory and the laboratory's interactions with the practicing obstetrician.

Genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) in ethnic populations in Texas; a report of a novel MTHFR polymorphic site, G1793A.

The importance of hyperhomocysteinemia, birth defects, and vascular diseases has been the subject of intense investigations. The polymorphic MTHFR mutations (C677T and A1298C) cause mild hyperhomocysteinemia, especially in homozygotes for C677T, but also in compound heterozygotes for C677T/A1298C. The subject of this report is the frequency of the polymorphic mutations in the MTHFR gene C677T, C1298A, and newly discovered mutation G1793A, as well as the association with MTRR polymorphic site A66G in different ethnic groups. Four ethnic groups were studied: African-Americans, Caucasians, Hispanics, and Ashkenazi Jews. There are statistically significant differences in the frequency of these alleles in the different populations studied, which impacts compound heterozygosity for such alleles in these populations. DNA samples obtained from the blood of healthy individuals of African-Americans, Hispanics, and Caucasians from south Texas were analyzed and compared to those obtained from Ashkenazi Jewish individuals. The polymorphic site, the G1793A allele, is least frequent among Ashkenazi individuals, 1.3%, compared to 6.9% among Caucasians (P = 0.001), 5.8% among Hispanics (P = 0.012), and 3.1% among African-Americans. The MTRR polymorphic site shows the lowest allele frequency among Hispanics, 28.6%, compared to 34% among African-Americans, 43.1% among Ashkenazi Jews (P = 0.002), and 54.4% among Caucasians (P < 0.0001). Statistically significant differences in allele frequencies of C677T and C1298A polymorphisms were also observed in these populations. Compound heterozygosity for multiple polymorphic alleles may play a role in birth defects and vascular diseases.