Patients with unexplained mismatch repair deficiency are interested in updated genetic testing.

BACKGROUND: Individuals who have colorectal or endometrial cancers displaying loss of immunohistochemical staining of one or more mismatch repair proteins without an identifiable causative germline pathogenic variant have unexplained mismatch repair deficiency (UMMRD). Comprehensive germline genetic testing for Lynch syndrome (LS) includes sequencing and deletion/duplication analysis of MLH1, MSH2, MSH6, and PMS2, deletion analysis of EPCAM, and MSH2 inversion analysis. Updated genetic testing to include elements of comprehensive LS testing not previously completed could further clarify LS status in individuals with UMMRD, allowing for tailored screening guidelines for affected individuals and their family members. However, patient understanding of the potential impact of updated genetic testing for LS is unclear. This study aimed to evaluate the interest in and perceived impact of updated genetic testing among individuals with UMMRD at a tertiary academic center. METHODS: A survey evaluating interest in and perceived impact of updated genetic testing was mailed to 98 potential participants. Electronic health record review was completed for all individuals meeting eligibility criteria. Thirty-one individuals responded to the survey. RESULTS: Results indicate this population is highly interested in updated genetic testing with the perceived impact being primarily for family members to have appropriate genetic testing and screening. Electronic health record review indicates that clinicians have an evolving understanding of causes of UMMRD, representing a potential change in assessment of cancer risk. CONCLUSIONS: Updated risk assessment and genetic counseling with a discussion of the benefits and limitations of germline and somatic genetic testing, is essential as the understanding of UMMRD and genetic testing recommendations for this population evolve.

Exploring experiences and expectations of prenatal health care and genetic counseling/testing in immigrant Latinas.

As the Latino population of the United States continues to increase, the specific needs of Latinos in genetic counseling continue to be unmet. Using culturally tailored genetic counseling responsive to the needs of the patient can assist in building rapport in genetic counseling sessions. We aimed to investigate the relationship between acculturation, prenatal care, genetic testing experiences, and expectations for prenatal care in an immigrant Latino population. A total of 20 Spanish-speaking, pregnant Latinas from various Latin American countries were interviewed after completing a prenatal genetic counseling session. The semi-structured phone interview included questions about the participants' experiences with genetic counseling/testing, prenatal health care in their home country, their current prenatal care in the United States, and information they felt to be important to know during their pregnancy. Although this study showed no statistically significant associations between acculturation, prenatal care, and genetic counseling/testing experiences, six significant content domains were identified as relevant to the participants. Overall, we found that immigrant Latinas desire to know prenatal risk information to help them prepare, relieve guilt, and help make screening/testing/family planning decisions. These Latinas reported the genetic counselor provided confidence, a sense of autonomy, and empowerment, for them to make their own decisions regarding prenatal screening/testing. The participants also spoke about stressors unique to the immigrant population, most notably being away from their older children and other family members. Identifying relevant factors about the lived experience of this population can help genetic counselors better address possible needs, feelings of guilt, and/or isolation and identifying women who could benefit from group-based prenatal care, support groups, or referrals to social work.

Somatic mismatch repair testing in evaluation of Lynch syndrome: The gap between preferred and current practices.

Lynch syndrome (LS) is a hereditary cancer predisposition syndrome primarily defined by increased risk for colorectal and uterine cancers. Individuals with germline pathogenic variants in the mismatch repair (MMR) genes (MLH1, MSH2/EPCAM, MSH6, and PMS2) are diagnosed with LS and recommended high-risk screening protocols to increase prevention and early detection of LS-related cancers. Tumor testing can help identify those at high risk for LS, but sometimes creates uncertainty with discordant screening and germline results, or unexplained mismatch repair deficiency (UMMRD). Somatic testing for MMR genes may help resolve UMMRD, potentially clarifying LS status and modifying cancer surveillance. However, guidelines for such testing are currently limited. This survey of cancer genetic counselors (GCs) aimed to examine current versus preferred ordering practices and interpretation of somatic MMR testing results in LS evaluation. Two hundred eligible GCs practicing in the United States and Canada were recruited from the National Society of Genetic Counselors. Participants answered questions regarding ordering practices, barriers to somatic MMR testing, theoretical scenarios, and desire for further guidelines. Statistical analysis was performed using chi-square, Fisher's exact, and Wilcoxon rank-sum tests, while themes were identified from free-text responses. Most respondents did not include somatic MMR testing in the LS work-up, despite three-quarters reporting they were 'somewhat comfortable' or 'extremely comfortable' with interpreting these results. Approximately half of participants indicated interest in ordering concurrent somatic MMR and germline testing for each of the four theoretical scenarios. Over three-quarters of individuals reported barriers to ordering somatic MMR testing, with cost and coordinating tissue samples most commonly cited. The frequently reported laboratory- and insurance-related barriers may contribute to the gap between preferred and current ordering practices for somatic MMR testing. Nearly all respondents endorsed additional guidelines for this testing, which could reduce barriers and inform screening recommendations for patients with UMMRD and their family members.

Introduction of cell-free DNA screening is associated with changes in prenatal genetic counseling indications.

The introduction of cell-free DNA screening, or non-invasive prenatal testing (NIPT), for chromosome abnormalities has greatly impacted prenatal care since its introduction in late 2011. We aimed to evaluate the association between the introduction of cell-free DNA screening and indication and referral patterns for genetic counseling at a large US academic medical center by comparing the percentage of each counseling indication between the time period prior to the introduction of cell-free DNA screening (2006-2011) and following its introduction (2012-2016) using multivariable Poisson regression models. Genetic counseling indications for positive carrier screens, average risk patients, abnormal ultrasound findings, and family history indications were significantly higher following the introduction of NIPT while advanced maternal age and abnormal maternal serum screening indications dropped significantly. We also showed that the uptake of amniocentesis dropped significantly after the introduction of cell-free DNA screening, while chorionic villus sampling uptake increased. These results provide evidence that the introduction of new genetic screening technologies is associated with a shift in genetic counseling referral indications and an increased uptake in genetic screening. Additional research is needed to explore the impact of expanded testing options on the need for genetic counseling services.

The utilization of prenatal microarray: A survey of current genetic counseling practices and barriers.

OBJECTIVE: We evaluated what prenatal genetic counselor's (GCs) practices, attitudes, and barriers are in regards to prenatal microarray since the publication of the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) guidelines for microarray use. METHODS: This was a survey-based cross-sectional study of English-speaking, board certified or eligible GCs who currently practice prenatal genetic counseling. RESULTS: Of 192 respondents, 183 (95%) have incorporated chromosome microarray (CMA) into clinical practice, with 64% believing that the benefits of CMA outweigh the harms and 52% agreeing that CMA should be offered to all women regardless of indication. Those who reported being experts/comfortable in their knowledge of CMA (85%) and familiar with current clinical guidelines (86%) were significantly more likely to offer CMA to patients undergoing invasive testing and patients with fetal anomalies. Patient-specific concerns were the largest reported barrier (51%) when GCs do not offer CMA to patients. CONCLUSION: Our study demonstrates GCs follow guidelines for CMA use when specific indications are involved, but further guidelines are needed regarding CMA use for other routine indications where utility of CMA is not clearly understood. On this basis, ACOG and SMFM should continue revising their guidelines as more information comes to light regarding utility of prenatal CMA for all indications, and organizations like the National Society of Genetic Counselors (NSGC) should consider publishing guidelines on prenatal CMA that are specialized to the GCs sphere of practice.

Genetic Testing Practices of Genetic Counselors, Geneticists, and Pediatric Neurologists With Regard to Childhood-Onset Neurogenetic Conditions.

Identifying genetic diagnoses for neurologic conditions with a considerable hereditary component, such as autism spectrum disorder, intellectual disability, and epilepsy, is critical to providing proper medical management for patients and their families. However, many patients with these conditions are not tested appropriately or receive no genetic testing at all. The current study was designed to characterize the genetic testing practices of the providers most likely to evaluate or order genetic testing for these patients: pediatric neurologists, geneticists, and genetic counselors. Significant variance was present between testing strategies selected by pediatric neurologists and those by geneticists and genetic counselors, supporting the need for updated genetic testing guidelines that are consistent across specialties. Pediatric neurologists also report lower confidence in ordering genetic testing and desire further education regarding genetic testing. Together, these results propose that continued integration of genetics providers, such as genetic counselors, into pediatric neurology clinics may improve utilization of genetic testing while reducing the burden on pediatric neurologists.

Undergraduate Student Perceptions and Awareness of Genetic Counseling.

Genetic counseling is a rapidly expanding field, and the supply of certified genetic counselors is currently unable to keep up with job demand. Research is fairly limited regarding the awareness and perceptions that prospective genetic counseling students have on the field and what factors most influence their interest. The current study includes data collected from 1389 undergraduate students in the sciences at 23 universities across the United States who were surveyed regarding information related to their awareness, perceptions, knowledge, and interest in genetic counseling. The majority of participants had heard of genetic counseling (78.0%), many from a high school course (37.3%), college course (28.1%), or online (11.5%). Familiarity was associated with factors such as female gender (p = 0.003) and length of time in school (p < 0.001). After taking the survey, participant interest was positively associated with several factors including female gender (p < 0.001) and Asian and Hispanic ethnicity (p = 0.012). Factors commonly reported as attractive about the field included direct patient care, the variety of roles available, cultural competency and psychosocial training, and helping others. Discussion elaborates upon specific factors related to student awareness and interest in genetic counseling and potential ways to tailor recruitment strategies for maximum benefit to the field.

National Society of Genetic Counselors Code of Ethics: Explication of 2017 Revisions.

The Code of Ethics (COE) of the National Society of Genetic Counselors (NSGC) was adopted in 1992 and was later revised and adopted in 2006. In 2016, the NSGC Code of Ethics Review Task Force (COERTF) was convened to review the COE. The COERTF reviewed ethical codes written by other professional organizations and suggested changes that would better reflect the current and evolving nature of the genetic counseling profession. The COERTF received input from the society's legal counsel, Board of Directors, and members-at-large. A revised COE was proposed to the membership and approved and adopted in April 2017. The revisions and rationale for each are presented.

Evaluating the NCCN Clinical Criteria for Recommending BRCA1 and BRCA2 Genetic Testing in Patients With Breast Cancer.

Background: Mutations in the BRCA1 and BRCA2 genes predispose individuals to a significantly elevated risk for breast and ovarian cancers. Identification of these individuals allows for proper screening, management, and testing of at-risk relatives. NCCN has established clinical criteria for recommending BRCA1/2 testing. Patients and Methods: A retrospective chart review of 1,123 patients with breast cancer was performed to evaluate the positive predictive values (PPVs) of 14 individual criteria for predicting BRCA1/2 mutations. Results: Two criteria had PPVs significantly below 10%. Only 2 of 115 patients who were recommended for testing based solely on the criterion of "diagnosed with breast cancer at ≤45 years of age" had pathogenic mutations at a PPV of 1.6% (95% CI, 0.2%-6.0%). Additionally, 0 of 37 individuals who underwent testing based on the criterion, "diagnosed with breast cancer at any age with ≥2 close blood relatives with breast cancer at any age" tested positive (95% CI, 0%-9%). Overall, meeting >1 criterion has a PPV of 12%, whereas meeting only 1 criterion has a PPV of 3.2% (95% CI, 1.6%-5.7%), significantly below 10% (P<.0001) for predicting BRCA1/2 positivity. Conclusions: Patients with breast cancer meeting >1 criterion constitute a population significantly enriched for BRCA1/2 mutations, whereas those meeting only 1 criterion test positive at a rate similar to unselected patients with breast cancer. These data will inform ongoing discussions regarding how to best implement BRCA1/2 genetic testing.

First Neonatal Demise with Travel-Associated Zika Virus Infection in the United States of America.

Zika virus is increasingly recognized as a fetal pathogen worldwide. We describe the first case of neonatal demise with travel-associated Zika virus infection in the United States of America, including a novel prenatal ultrasound finding. A young Latina presented to our health care system in Southeast Texas for prenatal care at 23 weeks of gestation. Fetal Dandy-Walker malformation, asymmetric cerebral ventriculomegaly, single umbilical artery, hypoechoic fetal knee, dorsal foot edema, and mild polyhydramnios were noted upon initial screening prenatal sonography at 26 weeks. A growth-restricted, microcephalic, and arthrogrypotic infant was delivered alive at 36 weeks but died within an hour despite resuscitation. The neonatal karyotype was normal. Flavivirus IgM antibodies were identified in the serum of the puerpera, once she disclosed that she had traveled from El Salvador to Texas in the early second trimester. Zika virus was identified in the umbilical cord and neonatal brain. Fetal arthritis may precede congenital arthrogryposis in cases of Zika virus infection and may be detectable by prenatal sonography. Physician and health care system vigilance is required to optimally address the significant and enduring Zika virus global health threat.

Attitudes Towards Prenatal Genetic Counseling, Prenatal Genetic Testing, and Termination of Pregnancy among Southeast and East Asian Women in the United States.

Recognizing the heterogeneity of the Asian population with regards to acculturation, education, health awareness, and cultural values is vital for tailoring culturally sensitive and appropriate care. Prior studies show that cultural values influence perceptions of genetics within Asian populations. The reputation of the family unit factors into decisions such as pregnancy termination and disclosure of family medical history, and the nondirective model of American genetic counseling may conflict with the historical Asian model of paternalistic health care. Previous studies also provide conflicting evidence regarding correlations between education, acculturation, age, and awareness and perceptions of genetic testing. The aims of this study were to describe attitudes towards prenatal genetics among Southeast and East Asian women living in the United States for varying amounts of time and to explore sociocultural factors influencing those attitudes. Twenty-three Asian women who were members of Asian cultural organizations in the United States were interviewed via telephone about their attitudes towards prenatal genetic counseling, prenatal genetic testing, and termination of pregnancy. Responses were transcribed and coded for common themes using a thematic analysis approach. Four major themes emerged. In general, participants: (1) had diverse expectations for genetic counselors; (2) tended to weigh risks and benefits with regards to genetic testing decisions; (3) had mixed views on termination for lethal and non-lethal genetic conditions; and (4) identified cultural factors which influenced testing and termination such as lack of available resources, societal shame and stigma, and family pressure. These findings may allow prenatal genetic counselors to gain a richer, more nuanced understanding of their Asian patients and to offer culturally tailored prenatal genetic counseling.

The psychosocial effects of the Li-Fraumeni Education and Early Detection (LEAD) program on individuals with Li-Fraumeni syndrome.

PURPOSE: In the past 5 years, new screening protocols have been developed that provide improved cancer screening options for individuals with Li-Fraumeni syndrome (LFS). Very little has been published on the psychosocial impact of these screening protocols. The goals of this study were to determine how participation in screening impacts individuals psychosocially, to examine the benefits and drawbacks of screening, and to evaluate possible barriers to continued screening. METHODS: We performed a qualitative study consisting of semistructured phone interviews conducted from December 2015 to February 2016 with 20 individuals attending the LFS screening program at MD Anderson Cancer Center. RESULTS: Data analysis showed that benefits of screening include early detection, peace of mind, centralized screening, knowledge providing power, and screening making LFS seem more livable. Perceived drawbacks included logistical issues, difficulty navigating the system, screening being draining, and significant negative emotional reactions such as anxiety, fear, and skepticism. Regardless of the emotions that were present, 100% of participants planned on continuing screening in the program. CONCLUSION: Our data indicate that the perceived benefits of screening outweigh the drawbacks of screening. Individuals in this screening program appeared to have improved psychosocial well-being because of their access to the screening program.Genet Med advance online publication 16 March 2017.

Knowledge and Self-Esteem of Individuals with Neurofibromatosis Type 1 (NF1).

Neurofibromatosis Type 1 (NF1) is a progressive genetic disorder characterized by physical findings such as café-au-lait macules, Lisch nodules, and neurofibromas in addition to other medical complications. Learning and social problems are more prevalent among individuals affected with NF1. It has been reported that people with NF1 have lower self-esteem (SE) when compared to the general population. Additionally, a study published over 20 years ago found that overall knowledge of NF1 was lacking in individuals affected with the condition. The goals of our study were to evaluate NF1 knowledge in adolescents and adults with the condition, as well as to determine if there is a link between patient knowledge and SE. Furthermore, we explored the impact of other factors, such as attendance at a NF1 support group and having a family history of NF1, on knowledge and SE. A survey comprised of knowledge-based questions and the Rosenberg Self-Esteem Scale was distributed to individuals with NF1 through the Texas NF Foundation. Overall, the 49 respondents (13 to 73 years of age) had a mean knowledge score of 77.9 % correct answers. Consistent with previous studies, the SE of our study population was lower when compared to general population norms. Although no correlation between knowledge and SE was observed, SE scores were on average higher if a person reported the following: having friends with NF1 (p = 0.009); attending a NF1 support group (p = 0.006); receiving care at a NF clinic (p = 0.049); or having received genetic counseling (p = 0.008). Further research is needed to better understand the relationship between these factors and SE in the NF1 population.

2013 Review and Update of the Genetic Counseling Practice Based Competencies by a Task Force of the Accreditation Council for Genetic Counseling.

The first practice based competencies (PBCs) for the field of genetic counseling were adopted by the American Board of Genetic Counseling (ABGC), 1996. Since that time, there has been significant growth in established and new work settings (clinical and non-clinical) and changes in service delivery models and the roles of genetic counselors. These changes prompted the ABGC to appoint a PBC Task Force in 2011 to review the PBCs with respect to their current relevance and to revise and update them as necessary. There are four domains in the revised PBCs: (I) Genetics Expertise and Analysis (II) Interpersonal, Psychosocial and Counseling Skills (III) Education and (IV) Professional Development and Practice. There are 22 competencies, each clarified with learning objectives or samples of activities and skills; a glossary is included. New competencies were added that address genomics, genetic testing and genetic counselors' roles in risk assessment, education, supervision, conducting research and presenting research options to patients. With PBCs serving as the pre-defined abilities or outcomes of training, graduating genetic counselors will be well prepared to enter the field with a minimum level of skills and abilities. A description of the Task Force's work, key changes and the 2013 PBCs are presented herein.

Influence of anchoring on miscarriage risk perception associated with amniocentesis.

One factor women consider when deciding whether to pursue amniocentesis is the risk of miscarriage. People use mechanisms like anchoring, or the prior belief regarding the magnitude of risk, as a frame of reference for new information. This study aimed to determine a woman's perception of miscarriage risk associated with amniocentesis before and after genetic counseling and to determine what factors anchor a woman's perception of miscarriage risk. One hundred thirteen women being seen for prenatal genetic counseling and possible amniocentesis at six Houston clinics participated in the two-part anonymous survey. While most women (56.7 %) perceived the risk as low or average pre-counseling and indicated the numeric risk of amniocentesis as <1 %, significantly more patients (73 %) correctly identified the numeric risk as <1 % post-counseling (p < 0.0001). However, the majority of patients' qualitative risk perception did not change after the genetic counseling session (60 %). Those who changed their feeling about the risk after counseling showed a decreased perception of the risk (p < 0.0001). Participants who elected amniocentesis had a significantly lower perception of the risk (p = 0.017) whereas those who declined amniocentesis were more likely to view the risk as high (p = 0.004). The only two anchoring factors that had an effect were having a friend or relative with a personal or family history of a genetic disorder (p = 0.001) and having a child already (p = 0.038); both were associated with a lower risk perception. The lack of significant factors may reflect the uniqueness of each patient's risk assessment framework and reinforces the importance of genetic counseling to elucidate individual concerns, particularly as non-invasive prenatal testing becomes more widely available and further complicates the prenatal testing landscape.

Is it all Lynch syndrome?: An assessment of family history in individuals with mismatch repair-deficient tumors.

PURPOSE: Mismatch repair-deficient (MMRD) colorectal cancer (CRC) and endometrial cancer (EC) may be suggestive of Lynch syndrome (LS). LS can be confirmed only by positive germ-line testing. It is unclear if individuals with MMRD tumors but no identifiable cause (MMRD+/germ-line-) have LS. Because LS is hereditary, individuals with LS are expected to have family histories of LS-related tumors. Our study compared the family histories of MMRD+/germ-line- CRC and/or EC patients with LS CRC and/or EC patients. METHODS: A total of 253 individuals with an MMRD CRC or EC from one institution were included for analysis in one of four groups: LS; MMRD+/germ-line-; MMRD tumor with variant of uncertain significance (MMRD+/VUS); and sporadic MSI-H (MMRD tumor with MLH1 promoter hypermethylation or BRAF mutation). Family histories were analyzed utilizing MMRpro and PREMM1,2,6. Kruskal-Wallis tests were used to compare family history scores. RESULTS: MMRD+/germ-line- individuals had significantly lower median family history scores (MMRpro = 8.1, PREMM1,2,6 = 7.3) than did LS individuals (MMRpro = 89.8, PREMM1,2,6 = 26.1, P < 0.0001). CONCLUSION: MMRD+/germ-line- individuals have less suggestive family histories of LS than individuals with LS. These results imply that MMRD+/germ-line- individuals may not all have LS. This finding highlights the need to determine other causes of MMRD tumors so that these patients and their families can be accurately counseled regarding screening and management.Genet Med 17 6, 476-484.

Perceptions of Latinas on the Traditional Prenatal Genetic Counseling Model.

The traditional genetic counseling model encompasses an individualized counseling session that includes the presentation of information about genes, chromosomes, personalized risk assessment, and genetic testing and screening options. Counselors are challenged to balance the provision of enough basic genetic information to ensure clients' understanding of the genetic condition in question with a personalized discussion of what this information means to them. This study explored the perceptions Latinas have about prenatal genetic counseling sessions and aimed to determine if they had preferences about the delivery of care. Data were collected through focus groups and one-on-one, semi-structured interviews of 25 Spanish speaking Latinas who received genetic counseling during their current pregnancy. We implemented grounded theory to evaluate participant responses, and were able to identify common emergent themes. Several themes were identified including an overall satisfaction with their prenatal genetic counseling appointment, desire for a healthy baby, peace of mind following their appointment, lack of desire for invasive testing, and faith in God. Several participants stated a preference for group genetic counseling over the traditional individual genetic counseling model. Our data indicate that Latinas value the information presented at prenatal genetic counseling appointments despite disinterest in pursuing genetic testing or screening and suggest that group prenatal genetic counseling may be an effective alternative to the traditional genetic counseling model in the Latina population.

Exploring the role of religiosity and spirituality in amniocentesis decision-making among Latinas.

Given the complex array of emotional and medical issues that may arise when making a decision about amniocentesis, women may find that their spiritual and/or religious beliefs can comfort and assist their decision-making process. Prior research has suggested that Latinas' spiritual and/or religious beliefs directly influence their amniocentesis decision. A more intimate look into whether Latinas utilize their beliefs during amniocentesis decision-making may provide an opportunity to better understand their experience. The overall goal of this study was to describe the role structured religion and spirituality plays in Latinas' daily lives and to evaluate how religiosity and spirituality influences health care decisions, specifically in prenatal diagnosis. Semi-structured interviews were conducted with eleven women who were invited to describe their religious beliefs and thoughts while considering the option of amniocentesis. All participants acknowledged the influence of religious and/or spiritual beliefs in their everyday lives. Although the women sought comfort and found validation in their beliefs and in their faith in God's will during their amniocentesis decision-making process, results suggest the risk of procedure-related complications played more of a concrete role than their beliefs.

Survival of Texas infants born with trisomies 21, 18, and 13.

Trisomies 21, 18, and 13 are the three most common trisomies among infants who survive to 20 weeks gestation or more. Overall information about birth prevalence, natural history, and mortality for all three trisomies is well defined, but information about ethnic-specific rates is limited. Only a few studies have examined mortality rates of trisomies 18 and 13 because so few cases are liveborn and most have very short life spans. This study assessed ethnic-specific population-based survival probabilities among infants for each trisomy. All cases of trisomies 21, 18, and 13 born in Texas between 1999 and 2003 were obtained from the Texas Birth Defects Registry and included 2,260 cases of trisomy 21, 398 cases of trisomy 18, and 213 cases of trisomy 13. Date and cause of death were obtained from the Texas vital statistics records and the National Death Index. Overall, birth prevalence rates (per 10,000 adjusted live births) for the three trisomies were 11.74 (95% CI: 11.25-12.25), 1.34 (95% CI: 1.18-1.52), 0.92 (95% CI: 0.79-1.07), respectively, and are consistent with previously reported rates. There were no differences in survival rates by ethnicity and the median survival for each trisomy was consistent with previous reports. The results of this study provide comprehensive population-based information for survival of infants with trisomies 21, 18, and 13.

Fetal trisomy 21 and the risk of preeclampsia.

OBJECTIVE: Microchimerism has been investigated as a possible contributor to the pathophysiology of preeclampsia. Although trisomy 21 is associated with pronounced microchimerism, it has not been connected with an increased risk of preeclampsia. Our objective was to readdress the relationship between preeclampsia and trisomy 21 in a large population. METHODS: Using the Texas Birth Defects Registry for 1999-2003, a cohort of 2995 pregnancies with a trisomy 21 fetus was identified and compared with a control cohort of 1959 pregnancies with fetal isolated oral clefts. Chi-square test was used to estimate the significance of observed difference in the proportion of preeclampsia between groups. The interactive and confounding effects of covariates were examined by stratified analysis and the Mantel-Haenszel method. RESULTS: We observed 84 cases of preeclampsia in the trisomy 21 cohort (3.7%) and 111 cases in the oral cleft cohort (5.7%). The crude OR for having preeclampsia in relation to trisomy 21 was 0.63 (95% CI 0.47-0.85). The OR estimates remained the same after adjustment for confounders. CONCLUSION: Pregnancies carrying a trisomy 21 fetus do not have an increased risk of preeclampsia. Besides epidemiologic significance, our data also have relevance for genetic counseling.