4 Ways to Identify McCune-Albright Syndrome

1. Notice Irregular Cafe-Au-Lait Spots

Unlike many other genetic disorders, McCune-Albright syndrome isn't always apparent at birth. If, however, your child is in the approximately 50 percent of patients who present with cafe-au-lait spots (flat, brown birthmarks) these may be used by his doctor as identifying marks of the syndrome. While children who don't have McCune-Albright syndrome can have somewhat similar birthmarks, the cafe-au-lait spots of MAS patients are easily distinguished. They typically have jagged borders and won't show up beyond the midline of your child's body, whereas in other children the birthmarks are evenly distributed on their bodies and have smoother edges.

2. Pay Attention to Bone Pain

Cafe-au-lait spots are merely one of the classic triad of abnormalities seen in children with McCune-Albright syndrome. Since the irregular birthmarks aren't seen in all patients, your child may not be diagnosed until early childhood when other symptoms begin to emerge. Polyostotic fibrous dysplasia, a condition in which normal bone tissue is replaced by soft, fibrous masses of cells, is another identifying symptom of McCune-Albright syndrome.

It can cause fractures in weight-bearing limbs and asymmetrical growth of facial and jaw bones, but often lies undetected until children begin to show symptoms. If your child begins to limp, her head circumference doesn't look right on growth charts at her regular checkups or she complains of unexplained and severe pain in her head, your doctor may order bone scans. These tests can confirm the presence of fibrous lesions and the hairline fractures they may have caused.

3. Precocious Puberty Is a Classic Sign

Standing alone, either cafe-au-lait spots or polyostotic fibrous dysplasia can be symptoms of other disorders. Combined, they point toward McCune-Albright syndrome. When joined by this third, most classic symptom of the triad, identification of the disorder is undeniable.

Precocious puberty is an endocrine problem in which the glands that produce and release puberty-inducing hormones activate early. The condition is more often seen in girls with MAS than in boys with the syndrome. You might think this is just because when a girl develops breasts, pubic hair and menstrual bleeding before the age of 8, it's much more noticeable than enlarged testes and other symptoms of puberty in boys, but that's not the case. It's actually because the mechanism causing precocious puberty in girls with MAS is different then in boys.

4. Test Girls' Blood Hormone Levels

Girls with McCune-Albright syndrome who exhibit precocious puberty typically have low levels of the gonadotropin hormones LH and FSH in their blood. This can be baffling to doctors, as it's usually abnormally high levels of these hormones that cause early puberty. In McCune-Albright, however, the cause is high levels of estrogen released into the bloodstream by ovarian cysts. Your daughter's doctor may order more blood tests to measure her estrogen levels and an ultrasound (or a series of ultrasounds) to visualize her ovaries.