The Genome

CMECNE

Klinefelter Syndrome: A Wide Range of Clinical Findings

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. Define the chromosomal complement of an individual with Klinefelter syndrome
2. Counsel patients as to possible hormonal therapeutic approaches in the treatment of Klinefelter 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 faculty, planners, and others in control of educational content to disclose all their financial relationships with ineligible companies. All identified conflicts of interest (COI) are thoroughly vetted and mitigated according to PIM policy. PIM is committed to providing its learners with high quality accredited continuing education activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of an ineligible company.

The PIM planners and others have nothing to disclose. The OBG Project planners and others have nothing to disclose.

Faculty: Susan J. Gross, MD, receives consulting fees from Cradle Genomics, 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 Jan 25 2023, 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?

Klinefelter syndrome is also known as XXY syndrome
- Present in 1 in 500 to 1 in 1000 newborn males
A sex chromosome abnormality that involves the presence of two or more X chromosomes and one Y chromosome
- Majority are 47,XXY karyotype
- Remaining cases are 48, XXXY or mosaic 46,XY/47,XXY
Prenatally, usually no obvious physical features detectable on ultrasound
In infancy, possible minor findings:
- Hypospadias and small or undescended testes
Clinical features may be subtle and often a diagnosis is not made until adolescence, adulthood, or not at all:
- Tall stature
- Small and atrophic testes
- Gynecomastia (excess breast tissue)
- Evidence of androgen deficiency such as decreased body hair
- Increased risk for breast cancer and autoimmune disorders (e.g. lupus)
Intellectual development:
- Individuals who have a 47,XXY karyotype usually have normal intelligence
- Starting in childhood, educational support may be needed to address learning disabilities, delayed speech and language development
- Individuals who have more than two X chromosomes are likely to have more severe symptoms
Treatment:
- Testosterone replacement is available and is usually started in early puberty
  - Treatment should be under the care of an endocrinologist and ideally with the collaboration of a multidisciplinary team
  - Recent data suggest treatment early in childhood may have a positive impact on neurodevelopment and social behaviors
- Removal of excess breast tissue is an option for cosmetic reasons and to reduce the risk for breast cancer
- Fertility treatment now available using assisted reproductive technology (ART), including testicular sperm extraction with intercytoplasmic sperm injection (TESE-ICSI)
- Academic educational support to assist with language-based learning disabilities (LLD) and motor planning issues

CAUSE:

Klinefelter syndrome is a condition caused by an abnormal karyotype (2 or more X chromosomes and one Y chromosome) that is present at the time of conception. It usually is the result of non-disjunction during meiosis and is either of maternal (55%) or paternal (45%) origin. It is a sporadic condition, not inherited.

KEY POINTS:

ACOG requires all women be offered prenatal screening (biochemical/cfDNA) or invasive testing (amniocentesis; CVS) to detect an increased risk or to diagnose aneuploidy, respectively
Currently, the only way to prenatally diagnose Klinefelter syndrome is through invasive testing (amniocentesis or CVS)
Klinefelter syndrome is now included on some cfDNA screening tests
Invasive testing is necessary to confirm any positive result on screening using cfDNA
If there is a history of Klinefelter syndrome, refer for genetic counseling

Learn More – Primary Sources:

NIH GARD –Klinefelter syndrome

NICHD – Klinefelter syndrome

US NLM – Genetics Home Reference: Klinefelter syndrome

Management of Klinefelter syndrome During Transition

Neurodevelopmental outcome of prenatally diagnosed boys with 47,XXY (Klinefelter syndrome) and the potential influence of early hormonal therapy

Oxandrolone Treatment Results in an Increased Risk of Gonadarche in Prepubertal Boys With Klinefelter Syndrome

Locate a Genetic Counselor or Genetics Services:

Genetic Services Locator-ACMG

Genetic Services Locator-NSGC

Genetic Services Locator-CAGC

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Klinefelter Syndrome: A Wide Range of Clinical Findings