OBJECTIVE To investigate the performance of first-trimester screening for aneuploidies by including assessment of tricuspid blood flow in the combined test of maternal age, fetal nuchal translucency (NT) thickness, fetal heart rate (FHR) and serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein A (PAPP-A). METHOD Screening by the combined test was per...

OBJECTIVES To assess thymic size expressed as the thymic-thoracic ratio (TT-ratio) in fetuses with trisomy 21, 18 or 13. METHODS The TT-ratio, the quotient of the anteroposterior thymic and the intrathoracic mediastinal diameter, was measured in 65 trisomic fetuses between 15 and 36 weeks' gestation, including 30 cases with trisomy 21, 19 with trisomy 18 and 16 with trisomy 13. In addition th...

The case of a 10-month-old girl with an extra G-like chromosome is presented. Quinacrine, trypsin-Giemsa, and reverse banding identified the extra chromosome as no. 22. The phenotype of the patient is unique in that unilateral iris coloboma was observed, unlike the 18 cases of full trisomy 22 already published. This represents the first reported case of full trisomy 22 with this coloboma, or 'c...

OBJECTIVE To develop a microarray-based method for noninvasive prenatal testing (NIPT) and compare it with next-generation sequencing. METHODS Maternal plasma from 878 pregnant women, including 187 trisomy cases (18 trisomy 13, 37 trisomy 18, 132 trisomy 21), was evaluated for trisomy risk. Targeted chromosomes were analyzed using Digital Analysis of Selected Regions (DANSR™) assays. DANSR pr...

Trisomy is the most common genetic abnormality in humans and is the leading cause of mental retardation. Although molecular studies that use a large number of highly polymorphic markers have been undertaken to understand the recombination patterns for chromosome abnormalities, there is a lack of multilocus approaches to incorporating crossover interference in the analysis of human trisomy data....

The natural history of trisomy 18 and trisomy 13 was investigated using data derived from parent questionnaires and medical records from 98 families with an index case of trisomy 18 and 32 families with an index case of trisomy 13. Data are presented on pregnancy, delivery, survival, medical complications, immunizations, growth, cause of death, cytogenetics, and recurrence risk. Half of the tri...

It is well known that varying degrees of mosaicism for Trisomy 21, primarily a combination of normal and Trisomy 21 cells within individual tissues, may exist in the human population. This involves both Trisomy 21 mosaicism occurring in the germ line and Trisomy 21 mosaicism documented in different somatic tissues, or indeed a combination of both in the same subjects. Information on the inciden...

BACKGROUND A beneficial consequence of screening for trisomy 21 is the early diagnosis of trisomies 18 and 13. Our objective was to examine the performance of first-trimester screening for trisomies 21, 18 and 13 by maternal age, fetal nuchal translucency (NT) thickness, fetal heart rate (FHR) and maternal serum-free beta-hCG and pregnancy-associated plasma protein-A (PAPP-A). METHODS Prospec...

We present preliminary results of a cross-sectional study which had the following objectives: 1--to develop percentile curves of weight, height and head circumference of Portuguese children with Trisomy 21 from 0 to 48 months of age; 2--a comparison of the growth of children with Trisomy 21 with a control population of their siblings, and 3--a comparison between the growth of Portuguese and Ame...

OBJECTIVE To examine the association between maternal serum levels of thyroid stimulating hormone (TSH) and free β-human chorionic gonadotrophin (free β-hCG) in trisomy 21, trisomy 18 and euploid pregnancies at 11-13 weeks and investigate the potential value of TSH in first-trimester screening for aneuploidies. METHODS Maternal serum TSH and free β-hCG levels at 11-13 weeks in 25 trisomy 21 a...