Klinefelter syndrome
Another mechanism for retaining the extra X chromosome is through a nondisjunction event during meiosis II in the female. Nondisjunction will occur when sister chromatids on the sex chromosome, in this case an X and an X, fail to separate. An XX egg is produced which, when fertilized with a Y sperm, yields XXY offspring.
Symptoms Affected males are almost always effectively sterile, although advanced reproductive assistance is sometimes possible. Some degree of language learning impairment may be present, and neuropsychological testing often reveals deficits in executive functions although these deficits can often be successfully ameliorated through early intervention. There may also be delays in motor development. XXY males may sit up, crawl, and walk later than other infants; they may also struggle in school, both academically and with sports.
Signs of Klinefelter syndrome at birth
The condition isn’t usually diagnosed at birth, because the baby boy looks healthy and unaffected. However, certain physical characteristics sometimes associated with Klinefelter syndrome may be apparent, including:
- small penis
- undescended testicles
- hypospadias (the urethra is located on the underside of the penis instead of the tip).
Signs of Klinefelter syndrome at childhood The appearance of signs of Klinefelter syndrome in childhood can vary greatly and range from mild to those that are more obvious. Many of the signs of Klinefelter syndrome also occur in children with other conditions, or children who do not have an underlying diagnosis, which makes detecting Klinefelter syndrome in childhood difficult.
Furthermore, many boys show no signs of Klinefelter syndrome during childhood. However, for those that do, early intervention provides the opportunity to overcome difficulties and for each boy to reach their individual potential. Signs that may be apparent in childhood include:
- delays in starting to talk or walk
- learning difficulties, including trouble listening or concentrating in class
- poor motor development or coordination (sometimes leading to shyness or an avoidance of rough sports)
- tiredness and fatigue
- reduced muscle strength or tone (sometimes leading to other complications such as sleep apnoea or chronic constipation).
Signs of Klinefelter syndrome at puberty
Klinefelter syndrome is often diagnosed at puberty, when the expected physical changes don’t occur. Some of the signs and symptoms of the condition include: small testicles (hypogonadism) – males with Klinefelter syndrome always have small testicles from puberty
- lack of facial, pubic and underarm hair
- poor muscle development
- breast tissue development (gynaecomastia)
- unexplained weight gain, especially on the stomach or trunk
- tiredness and fatigue
- small penis
- disproportionately long arms and legs compared to the length of the body
- taller than average height
- poor concentration
- single crease in the palm (simian crease)
- difficulties with sexual functioning
- speech and learning difficulties – in some cases this can lead to behavioural problems
- sadness, lowered mood or depression.
Boys may become particularly self-conscious in puberty when they notice that their body is not undergoing the same changes as their peers. Testosterone replacement therapy can help the body to undergo these changes.
Most males with Klinefelter syndrome are not diagnosed until they are well into adulthood, when diagnosis can come as a major shock. An earlier diagnosis provides opportunities for the child and his family to access treatments and interventions that can help overcome any difficulties associated with the condition.
Diagnosis Klinefelter syndrome is diagnosed using a number of tests, including:
- physical examination – all males with Klinefelter syndrome have small testicles, which can be detected by genital examination
- chromosome analysis – will confirm the diagnosis
- blood tests – can check for hormone levels
- semen examination – checks fertility
Treatment There is no cure for Klinefelter syndrome. Treatment aims to correct some aspects of the condition and provide emotional support. Options may include:
- hormone therapy – such as testosterone, to help bring on the usual changes of puberty. Hormone therapy will need to be lifelong, however it can have a broad range of benefits, including increased energy levels and physical strength
- reproductive technologies – such as IVF, to help men with Klinefelter syndrome become fathers. New advances in reproductive technologies mean that up to a quarter of men with Klinefelter syndrome are now able to have their own biological children
- educational support – if necessary
- speech therapy – if necessary
- physical or occupational therapy – if necessary
- cosmetic surgery – to remove enlarged breast tissue
- counselling – to help the male come to terms with his condition
- frequent screening tests – to ensure the early diagnosis of any associated complications (such as diabetes or breast cancer).
