Sex Chromosome Aneuploidies (SCA)

Most people have either two X chromosomes or one X and one Y chromosome in their cells. People with a sex chromosome aneuploidy (SCA) have a different number of X and/or Y chromosomes.

The Harmony test looks for SCAs such as:

Monosomy X (a cause of Turner syndrome)
XXY (a cause of Klinefelter syndrome)
XXX
XYY
XXYY

People with SCAs can have birth defects, infertility and learning differences. Some people with an SCA have such subtle features that the condition isn’t identified until after childhood.

Monosomy X (a cause of Turner syndrome)

Monosomy X is a condition in which a female has one X chromosome and no second sex chromosome. It occurs in about 1/2500 births¹ and is not typically inherited. Features are variable and can include endocrine (hormone) issues, heart defects and infertility.¹

For more detailed information about Monosomy X, including pregnancy management, health care guidelines, advocacy and support for families:

XXY (a cause of Klinefelter syndrome)

XXY is a condition in which a male has two X chromosomes and one Y chromosome. It occurs in 1 in 500 to 1 in 1000 births² and is typically not inherited. Features are variable and often subtle, and largely involve the endocrine (hormone) system.²

For more detailed information about XXY, including pregnancy management, health care guidelines, advocacy and support for families:

References

U.S. National Library of Medicine. Genetics Home Reference. Turner Syndrome. https://ghr.nlm.nih.gov/condition/turner-syndrome. Accessed January 28, 2021.
U.S. National Library of Medicine. Genetics Home Reference. Klinefelter Syndrome. https://ghr.nlm.nih.gov/condition/klinefelter-syndrome. Accessed January 28, 2021.