Information on the following diseases can be found in the Related Disorders section of this report:

• Conradi-Hunermann Syndrome
• Ichthyoses

CHILD syndrome is usually present at birth. It may first become apparent at some point during the first month of life.

The skin is usually dry, itchy, red and scaly (ichthyosiform erythroderma) on one side of the body, although minor skin involvement in the shape of lines or segments may occur on the opposite side of the body. Bands of normal skin may be found on the affected side as well. Patients with CHILD syndrome may be bald on one side of the head and have clawlike nails.

Limb defects usually occur on the same side of the body as the major skin symptoms. These defects may range from underdevelopment of fingers and toes to complete absence of a limb. Some of the types of skeletal defects that might occur include abnormal ribs, anomalies of the shoulder blades (scapula), webbing of the skin between joints, and absence of muscles of the breast (pectoral).

Heart defects sometimes associated with this syndrome include defects in the walls between auricles and/or ventricles, as well as complex heart disease in which less than adequate amounts of oxygen get to the organ (cyanosis).

Abnormalities of the central nervous system, blood vessels, kidneys, thyroid, lungs and adrenal glands, and of the reproductive and urinary system, may also occur. Most of these abnormalities result from underdevelopment of the affected side of the body.

CHILD syndrome is a hereditary disorder transmitted as an X-linked dominant trait. The faulty gene is on the long arm of the X chromosome (Xq28). The protein/enzyme product coded by the gene has been identified as NSDHL and governs an essential step in the biosynthesis of cholesterol.

Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated "p" and a long arm designated "q". Chromosomes are further sub-divided into many bands that are numbered. For example, "chromosome Xq28" refers to band 28 on the long arm of the X-chromosome. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

Genetic diseases are determined by the combination of genes for a particular trait which are on the chromosomes received from the father and the mother.

Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

X-linked dominant disorders are caused by an abnormal gene on the X chromosome, but in these rare conditions, females with an abnormal gene are affected with the disease. Males with an abnormal gene are more severely affected than females, and many of these males do not survive.

Only about 30 cases have been reported in the United States and of these 29 involved infant girls and only 1 involved a boy. Of these 30 cases, only 6 cases involved organs or systems on the left side of the body.

Symptoms of the following disorders may resemble those of CHILD Syndrome. Comparisons may be useful for a differential diagnosis:

Conradi-Hunermann Syndrome is a form of Chondrodysplasia Punctata. It is a rare inherited disorder affecting infants and young children. This disorder is characterized by mild to moderate growth deficiencies including a shortened neck and slowed growth of arms or legs. Unusual facial characteristics, large skin pores and sparse hair that tends to be coarse may also occur. (For more information, choose "Conradi-Hunermann Syndrome" as your search term in the Rare Disease Database.)

"Ichthyoses" or "Disorders of Cornification" are general terms describing a group of scaly skin disorders. They are characterized by an abnormal accumulation of large amounts of dead skin cells (squames) in the top layer of the skin. The conversion of an abnormally large number of epidermal cells into squamous cells is thought to be caused by a defect in the metabolism of skin cells known as "corneocytes" or of the fat-rich matrix around these cells. The cells can be thought of as bricks, while the matrix would be the mortar holding these cells together. (See "Ichthyosis" in the Rare Disease Database.)

Other forms of Ichthyosis include Sjogren-Larsson Syndrome, Netherton Syndrome, Ichthyosis Hystrix, Lamellar Ichthyosis, Refsum Syndrome, Darier Disease, Chanarin-Dorfman Syndrome, and Epidermolytic Hyperkeratosis. (Choose the appropriate name as your search term for more information on that disorder in the Rare Disease Database.

Diagnosis
A thorough physical exam may be sufficient for the diagnosis.

Treatment
Skin (dermatologic) symptoms of CHILD syndrome are treated by applying skin softening (emollient) ointments, preferably plain petroleum jelly. This can be especially effective after bathing while the skin is still moist. Salicylic acid gel is another particularly effective ointment. The skin should be covered at night with an airtight, waterproof dressing when this ointment is used. Lactate lotion can also be an effective treatment for the skin symptoms of this disorder.

Drugs derived from Vitamin A (retinoids) such as tretinoin, motretinide, and etretinate can be effective against dermatologic symptoms of CHILD syndrome, but can cause toxic effects on the bones in some cases. A synthetic derivative of Vitamin A, isotretinoin (accutane), when taken by pregnant women, can cause severe birth defects to the fetus. These Vitamin A compounds have not yet been approved by the Food and Drug Administration (FDA) for treatment of Ichthyosis.

Other treatment is symptomatic and supportive. Genetic counseling may be helpful to families of patients with CHILD syndrome.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

TEXTBOOKS
Sybert VP. Ichthyosis. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:120-21.

Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:831-32.

Champion RH, Burton JL, Ebling FJG, eds. Textbook of Dermatology. 5th ed. Blackwell Scientific Publications. London, UK; 1992:1329-65.

REVIEW ARTICLE
Happle R, Mittag H, Kuster W. The CHILD nevus: a distinct skin disorder. Drermatology. 1995;191:210-16.

JOURNAL ATICLES
Caldas H, Herman GE. NSDHL, an enzyme involved in cholesterol biosynthesis, traffics through the Golgi and accumulates on ER membranes and on the surface of lipid droplets. Hum Mol Genet. 2003 Sep 23

Hummel M, Cunningham D, Mullett CJ, et al. Left-sided CHILD syndrome caused by a nonsense mutation in the NSDHL gene. Am J Med Genet. 2003;122A:246-51.

Konig A, Happle R, Fink-Puches R, et al. A novel missense mutation of NSDHL in an unusual case of CHILD syndrome showing bilateral, almost symmetric involvem,ent. J Am Acad Dermatol. 2002;46:594-96.

Grange DK, Kratz LE, Braverman NE, et al. Child syndrome caused by deficiency of 3beta-hydroxysteroid-delta8, delta7-isomerase. Am J Med Genet. 2000;90:328-35.

FROM THE INTERNET
Foundation for Ichthyosis & related Skin Types. (FIRST). About Ichthyosis. CHILD Syndrome. nd. 2pp.
www.scalyskin.org/content.cfm?ContentID=94&ColumnID=14

Aymé S. CHILD syndrome. September 2002. 2pp.
www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=139

Fenske NA, Roshdieh B. CHILD Syndrome. emedicine. Last updated: September 15, 2003. 7pp.
www.emedicine.com/derm/topic75.htm