DEAR DR. DONOHUE: Our granddaughter is 8 years old and small for her age. She has been tested for a number of things, but all tests have come back without indicating what could be wrong. She is now seeing a geneticist, who believes she has Turner’s syndrome. What is this all about? She’s active and intelligent. – Worried

ANSWER: Humans have 23 pairs of chromosomes. Chromosomes are chains of genes. Genes, in turn, are the blueprints for how we are made. One pair of chromosomes determines a person’s sex. Girls have an XX pair, and boys an XY pair.

In Turner’s syndrome, a baby girl is born with only one X chromosome or with only a partial copy of the second X chromosome. One result of this chromosome lack is short stature. A Turner’s child, without any treatment, can expect a full adult height of about 4 feet, 8 inches.

Turner’s brings with it many other possible consequences. Most Turner’s girls fail to menstruate and are infertile. The heart and kidneys must be carefully checked, since abnormalities of these organs are common. However, the changes of Turner’s also can be so slight that they are either never recognized or not recognized until later in life.

The missing chromosome cannot be restored. But growth hormone sparks an increased height for these girls, and female hormones foster the development of sexual characteristics like breast growth. The Turner Syndrome Society is a source of information and support for affected girls and their families. Its Web site is www.turnersyndrome.org and its toll-free number is 800-365-9944.

DEAR DR. DONOHUE: My best friend’s 17-year-old son was just diagnosed with Wilson’s disease. He hasn’t been himself for quite some time. At first they thought he had psychological problems, and then they said he had hepatitis. Then the boy started stumbling, and that’s when the diagnosis was finally made. Our circle of friends has never heard of this. Is it treatable? – L.J.

ANSWER: Wilson’s disease is a genetic disease in which too much copper is stored in the body. The overload of copper brings on a large number of unrelated signs and symptoms.

The boy did have hepatitis, but not the usual viral hepatitis. He had liver inflammation because of copper infiltrating the organ. Psychological problems are another aspect of the illness. Copper can make its way into the brain and cause a number of serious consequences. The boy’s stumbling was probably on that basis.

Medicines can bind copper and eventually remove it from the body. It can take some time before improvement is seen.

When liver damage is severe and irreparable, liver transplantation is the treatment.

DEAR DR. DONOHUE: On his first birthday, my son had a high temperature but was eating and active. Two days later, he broke out in a rash, and I rushed him to our doctor. The doctor said it was a herpes-6 infection and there is no medicine for it.

The baby was fine in about a week. His grandmother, my mother-in-law, isn’t. She thinks this was a sexually transmitted disease and that we should report it to the police. Is it? Neither my husband nor I have had such an illness, and I stay with this baby every day. No one else cares for him. – R.T.

ANSWER: It’s the “herpes” word that has your mother-in-law up in arms. This illness is better known as roseola. Roseola is a common childhood illness caused by the herpes-6 virus. That virus is a distant – very distant – relative of the genital herpes virus, but it is not transmitted sexually and does not cause an illness the least bit similar to genital herpes. Children younger than 2 years old constitute 90 percent of those infected.

The illness starts with a rise in temperature to 101 F (38.3 C) or higher. Even with a fever, most infected babies carry on normally, eating and moving about as usual. The fever stays for about three days and breaks suddenly. Then the baby develops a pink rash that looks like measles. It starts on the trunk and spreads to the neck, face, arms and legs. The rash stays two to three days. And that’s it for this illness.

The infection is almost never dangerous, so no antiviral medicines are prescribed.For everyone’s peace of mind, it would be better to call this illness “roseola” and not “herpes-6 virus infection.” No misinterpretation occurs with “roseola.” You don’t need to report this to authorities.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com