Down Syndrome / Trisomy 21: Clinical Findings and Prenatal Considerations

Learning Objectives and CME/Disclosure Information

This activity is intended for healthcare providers delivering care to women and their families.

After completing this activity, the participant should be better able to:

1. List common physical findings seen in Down syndrome
2. Counsel parents on what to expect regarding social interactions related to Down syndrome

Estimated time to complete activity: 0.25 hours

Faculty:

Susan J. Gross, MD, FRCSC, FACOG, FACMG
President and CEO, The ObG Project

Disclosure of Conflicts of Interest

Postgraduate Institute for Medicine (PIM) requires instructors, planners, managers and other individuals who are in a position to control the content of this activity to disclose any real or apparent conflict of interest (COI) they may have as related to the content of this activity. All identified COI are thoroughly vetted and resolved according to PIM policy. PIM is committed to providing its learners with high quality CME activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of a commercial interest.

Faculty: Susan J. Gross, MD, receives consulting fees from Genoox, Inc., and has financial interest in The ObG Project, Inc.

Planners and Managers: The PIM planners and managers, Trace Hutchison, PharmD, Samantha Mattiucci, PharmD, CHCP, Judi Smelker-Mitchek, MBA, MSN, RN, and Jan Schultz, MSN, RN, CHCP have nothing to disclose.

Method of Participation and Request for Credit

Fees for participating and receiving CME credit for this activity are as posted on The ObG Project website. During the period from Dec 31 2017 through Dec 31 2020, participants must read the learning objectives and faculty disclosures and study the educational activity.

If you wish to receive acknowledgment for completing this activity, please complete the post-test and evaluation. Upon registering and successfully completing the post-test with a score of 100% and the activity evaluation, your certificate will be made available immediately.

For Pharmacists: Upon successfully completing the post-test with a score of 100% and the activity evaluation form, transcript information will be sent to the NABP CPE Monitor Service within 4 weeks.

Joint Accreditation Statement

In support of improving patient care, this activity has been planned and implemented by the Postgraduate Institute for Medicine and The ObG Project. Postgraduate Institute for Medicine is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

Physician Continuing Medical Education

Postgraduate Institute for Medicine designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Continuing Nursing Education

The maximum number of hours awarded for this Continuing Nursing Education activity is 0.2 contact hours.

Read Disclaimer & Fine Print

WHAT IS IT?

Down syndrome is the most common chromosomal cause of intellectual disability
May affect almost every organ system but the following findings are particularly common and may be identified on prenatal sonogram:
- Increased nuchal translucency (first trimester) and/or nuchal fold (second trimester) or cystic hygroma
- Congenital heart disease (50%), particularly AV canal defects
- Duodenal atresia (double bubble sign) usually identified in 3rd trimester
- Prenatal ultrasound markers include: short femurs, echogenic intracardiac foci, dilated renal pelviectasis, mild ventriculomegaly
Other findings may not be apparent until postnatal life:
- Dysmorphic features: epicanthal folds, single palmar crease, low set ears
- Decreased muscle tone
- Intellectual disability: usually in the mild (IQ ~70) to moderate range (IQ ~50)
  - Most individuals with Down syndrome can participate in numerous group and individuals activities, but may need some level of supervision throughout their lives
  - Individualized education programs can help children with Down syndrome reach their potential
  - Special education services at school can range from inclusion in the typical classroom with extra help to small group instruction
- Hearing loss (up to 75%)
- Sleep apnea (50-75%)
- Eye disease, such as cataracts (50-70%)
- Endocrine disease: thyroid, diabetes
- Hirschsprung disease
- Leukemia is slightly increased in this population, typically requiring lower doses of chemotherapy treatments
- Plaques are frequently seen in older adults with Down syndrome (50+ years) but their presence does not mean that Alzheimer’s disease will necessarily develop – other treatable causes of decline are investigated first

CAUSE:

Down syndrome (DS) is a condition caused by the presence of an extra chromosome (#21) at the time of conception. In 90% of cases, it is the result of nondisjunction during meiosis (Trisomy 21), which is usually a sporadic occurrence. In 4-5% of DS affected individuals a chromosomal imbalance is the cause, inherited from a parent who has a balanced karyotype (i.e. Robertsonian translocation). A small proportion of affected individuals, < 1%, are diagnosed with mosaic DS.

KEY POINTS:

ACOG requires all women be offered prenatal screening (biochemical/cfDNA) or invasive testing (amniocentesis;CVS) to detect an increased risk for DS, or to diagnosis it, respectively
Children with Down syndrome are more similar to other children than they are different
Overall, this condition is present in approximately 1 in 800 live births. Risk increases with maternal age
- At maternal age 25, the risk is 1/1250
- At maternal age 35, the risk is 1/365
- At maternal age 40, the risk is 1/110
- At maternal age 45, the risk is 1/32
If there is a family history or previous DS pregnancy, refer for genetic counseling
Data is limited on obstetrical management of an ongoing pregnancy with trisomy 21
- Increased risk of fetal loss (5.9%), growth restriction (17.5%) and anomalies (75.0%)
- Non-reassuring fetal surveillance (35.9%) appears to be associated with placental insufficiency and not necessarily related to structural anomalies
- Data suggests a role for antepartum surveillance