How Can I Detect It?
Print PageBabies and Toddlers
A geneticist can diagnose Klinefelter syndrome before your son is born through a fetal cytogenetic analysis. Your pediatrician may suspect Klinefelter syndrome if your infant son has
- Developmental delay
- Undescended testicles (cryptorchidism)
- Pea-sized testicles
- Hypospadias (urine dribbles out of an opening on the underside of his penis)
However, 75% of boys with Klinefelter syndrome develop normal height and weight until they reach age 4 or 5. In 25% of boys, there is a telltale condition called clinodactyly, where the little finger curves toward the ring finger because the middle bone is wedge-shaped instead of rectangular.
School-age Boys
Your pediatrician may investigate your school-age son for Klinefelter syndrome if he has this characteristic appearance:
- Tall stature
- Knock-knees (genu valgum)
- High arches (pes cavus)
- Protruding lips
- Projecting jaw (prognathism)
- Very widely-spaced eyes (hypertelorism)
- If he is Caucasian or Black, epicanthal skin folds on his upper eyelids at the inner corner, giving him an oriental look
- Poor coordination
- Fused bones in his forearms that make it difficult for him to rotate his arms (radioulnar synostosis)
- Quiet, tractable personality with occasional tantrums and aggression
You may ask your pediatrician to investigate your son for Klinefelter syndrome if he has:
- Attention Deficit Disorder (ADD)
- Learning disability (especially dyslexia, reading difficulty, and data retrieval problems)
- Mental retardation (IQ drops 15 points for each additional X chromosome)
- Poor expressive and receptive language skills
- Poor short term memory
- Osteoporosis (bone thinning)
- Lack of sporting ability
Puberty
Your doctor may suspect Klinefelter syndrome when your boy reaches puberty if he has:
- High-pitched voice
- Sparse beard and body hair
- Gynecomastia (enlarged breasts)
- Feminine fat distribution
- Taurodontism (enlarged molar teeth)
- Breast cancer or germ cell tumors from elevated estradiol
If your doctor suspects your son has the androgen deficiency that accompanies Klinefelter syndrome, he will likely be sent to a lab for these blood tests:
- FSH (follicle stimulating hormone)
- LH (luteinizing hormone)
- Estradiol
- Testosterone
You may ask your doctor to perform genetic screening for Klinefelter syndrome if your son exhibits:
- Inability to deal with stress
- Psychological problems, like anxiety, neurosis, depression, or psychosis