XX, XY, XXY: Klinefelter Syndrome

In the past six months I have been approached by several people who have Klinefelter Syndrome, a genetic condition that often goes undiagnosed. Klinefelter Syndrome is an aneuploid genetic condition, in which a biological male has an extra X-chromosome, not XY but XXY. Having an additional X-chromosome does not provide any superpowers or advantages in life. In fact it creates some bumps on that path. Aneuploidy simply means the presence of an abnormal number of chromosomes in a cell: instead of 46, they can have 45 or 47. This endocrine disorder was first discovered in 1942.

Worldwide the estimate is one of 500 males born will have some variation of Klinefelter Syndrome, and a recent study estimates that half of those are unaware they have it. About 80% of Klinefelter cases possess the 47XXY karyotype. The remaining 20% either have the higher aneuploidy karyotype 48XXYY, a more severe form, or one of the mosaicism karyotypes 46XY or 47XXY, the milder forms of the genetic disorder. A karyotype is the complete set of chromosomes for a particular species or organism, you know, like us primates. It also refers to the imaging of a person’s chromosomes.

Klinefelter Syndrome can be diagnosed through karyotyping, a blood test designed to look for chromosomal abnormalities. Hormone testing for low testosterone can be done, and a prenatal amniotic fluid chorionic villus in the placenta can also be checked for chromosomal abnormalities.

There are different degrees of Klinefelter syndrome. For example, some males have the  extra chromosome in only some of their cells, resulting in a milder syndrome, and this is referred to as mosaic Klinefelter syndrome. Males with more than one additional chromosome (XXXY) tend to have more severe symptoms that those with the mosaic version. These variants are rarer, occurring in about one in 50,000 births.

Symptoms can help parents and caregivers spot Klinefelter syndrome in young males. Babies can show delay in motor-skill development, reduced muscle development and strength, smaller testicles, low testosterone or weak bones. As these males age, they may have delayed puberty, smaller testicles, broader hips, a tall, thin stature, reduced sex drive, increased belly fat, or even some defects in cognition.

A mild case, as evidenced by hormonal testing, may not require treatment. If it is more than mild, it’s important to seek hormonal therapy at the onset of puberty. Males with low testosterone are at increased risk of developing osteoporosis, breast cancer (yes, men get this more often than you think), diabetes, autoimmune conditions like lupus, heart disease, blood-vessel complications, anxiety or depression, infertility, or poor sexual function.

It’s estimated that 10% of the boys with this disorder also have a diagnosis placing them on the autism spectrum. Boys with Klinefelter are taller than 60% of their counterparts by age eight. Males with this disorder tend to be taller, have narrower shoulders, longer legs, wider hips, and a larger arm span than men with 46 chromosomes. This syndrome does not appear to affect life expectancy. It’s further estimated that half the males living with this are undiagnosed. If you are a parent of a male or a male who has experienced any of these symptoms, you may want to get your testosterone checked, and if need be a karyotype test to determine whether this is what is affecting you or your child.

These symptoms and effects can be mitigated using testosterone replacement therapy, particularly at the onset of puberty, which will promote muscle development, increase the strength of body and bones, and promote body-hair growth. Early diagnosis is the key to mitigating these problems. One way to optimize potential is to test for the syndrome and treat it, allowing men the medical, educational support necessary for them to have a fulfilling life and their own families.

This is Hedda Fay reminding everyone to be kind to one another, you do not know what syndrome a person may have that affects their appearance or journey in life. Be grateful their burden is not your own, and be supportive however you can. We are all neighbors here, we share public toilets and leisure areas, let’s be a community for each other. If you have an idea for an article, email me! I appreciate all reader feedback and commentary.