Course : MOC Part IV: Turner Syndrome and Klinefelter Syndrome

Turner syndrome

Turner syndrome is a common disorder due to aneuploidy of the sex chromosomes. This MOC provides practice performance assessments for a total of 5 patients with TS.

Turner syndrome (TS) is used to describe phenotypic females who have characteristic physical features and complete or partial absence of the second sex chromosome, with or without cell line mosaicism.  It occurs in 1 in 2500 to 1 in 4000 live-born females.  Within the definition of Turner syndrome, the following are specifically excluded:

  • Those with a 45,X cell line but without clinical features of TS
  • Phenotypic males, regardless of karyotype
  • Small terminal deletions of Xp that do not include Xp22.3, which may lead only to short stature
  • Deletions of Xq distal to Xq24  for which the diagnosis of premature ovarian failure is more appropriate

The clinical features of Turner syndrome vary widely among affected females and typically include growth failure, pubertal delay, lymphedema of the hands and/or feet, structural heart defects (most commonly coarctation of the aorta and/or bicuspid aortic valve), and learning disabilities.

Klinefelter Syndrome

Klinefelter syndrome (47,XXY) is one of the most common sex chromosome abnormalities, affected approximately 1 in 660 newborn males.  Approximately 20% of males with Klinefelter syndrome have a higher grade aneuploidy (such as 48,XXXY) or mosaicism (47,XXY/46,XY).  The phenotype of individuals with Klinefelter syndrome is also variable, with the most consistent features being hypergonadotropic hypogonadism, primary testicular failure with reduced testicular volume, tall stature, central adipose distribution, and psychosocial, behavioral, developmental and learning difficulties.

Please review up to 5 charts for patients with Klinefelter syndrome seen by you in the past five years and check the following items if completed and documented in the medical record.   Items do not have to be completed within a single visit. Some items may not be applicable for the patient whose chart you are reviewing. Please select “NA” for “not applicable” to prevent an incorrect deduction in score (unless the item should have been completed as part of the evaluation).  Additionally, the Assessment section of the chart has been divided into sections based on the patient’s age at last evaluation.  You need only fill in the Assessment section that pertains to the age of your patient at last evaluation; please use “NA” for the other ages in the Assessment section.


ACMG Members and ACMG Trainees ($25)
Non-members ($75)

  Purchase with Educational Credit