Ambras syndrome

Synonyms

Hypertrichosis universalis congenita Ambras type
Congenital generalized hypertrichosis, Ambras type
HTC 1

Overview

Ambras syndrome is a very rare type of hypertrichosis lanuginosa congenita, a congenital skin disease characterized by excessive hair growth on the entire body, with the exception of the palms, soles, and mucous membranes. Individuals with Ambras syndrome have excessive growth of vellus (soft, fine and short) hair, especially on the face, ears, and shoulders. Facial and dental abnormalities may also be present. Ambras syndrome has been mapped to the short (q) arm of chromosome 8. It appears to follow an autosomal dominantpattern of inheritance.

Symptoms

The primary characteristic of all forms of hypertrichosis is excessive hair. Hair in hypertrichosis is usually longer than expected and may consist of any hair type (lanugo, vellus, or terminal).  Patterned forms of hypertrichosis cause hair growth in patterns. Generalized forms of hypertrichosis result in hair growth over the entire body. Circumscribed and localized forms lead to hair growth restricted to a certain area.

  • Excessive hair growth
  • Dysmorphic features

Causes

Genetic:

 

Hypertrichosis lanuginosa
Congenital hypertrichosis lanuginosa may be caused by an inverse mutation on the 8q chromosome; however, it could also be possibly the result of a spontaneous genetic mutation rather than inheritance. This form is a dominant autosomal (not located on the sex chromosomes) cutaneous disorder, that affects the skin.
Generalized hypertrichosis
Congenital generalized hypertrichosis has a dominant pattern of inheritance and has been linked to chromosome xq24-q27.1. An affected female (carrying the hypertrichosis gene) has a 50% chance of passing it to her offspring. An affected male will pass this form of hypertrichosis to his daughters, but never the sons.

Generalized hypertrichosis terminalis
Congenital generalized hypertrichosis terminalis is thought to be caused by genetic changes on chromosome 17 resulting in the addition or removal of millions of nucleotides. The gene MAP2K6 may be a factor contributing to this condition. This condition may also be due to the change in the chromosome affecting the transcription of genes.

Medical conditions:
Acquired hypertrichosis lanuginosa is commonly present with cancer. This condition is also linked to metabolic disorders, such as anorexia, hormone imbalances, such as hyperthyroidism, or as a side effect of certain drugs.

Acquired generalized hypertrichosis may be caused by cancer. The resulting hair growth is known as malignant down. The mechanism behind cancer induced hypertrichosis is unknown. Oral and topical minoxidil treatments are also known to cause acquired generalized hypertrichosis.

Diagnosis

Hypertrichosis is diagnosed clinically via the occurrence of hair in excess of what is expected for age, sex, and ethnicity in areas that are not androgen-sensitive. The excess can be in the form of excessive length or density and may consist of any hair type (lanugo, vellus, or terminal).

Treatment

There is no cure for any congenital forms of hypertrichosis. The treatment for acquired hypertrichosis is based on attempting to address the underlying cause. Acquired forms of hypertrichosis have a variety of sources, and are usually treated by removing the factor causing hypertrichosis, e.g. a medication with undesired side-effects. All hypertrichosis, congenital or acquired, can be reduced through hair removal. Hair removal treatments are categorized into two principal subdivisions: temporary removal and permanent removal. Treatment may have adverse effects by causing scarring, dermatitis, or hypersensitivity.

Temporary hair removal may last from several hours to several weeks, depending on the method used. These procedures are purely cosmetic. Depilation methods, such as trimming, shaving, and depilatories, remove hair to the level of the skin and produce results that last several hours to several days. Epilation methods, such as plucking, electrology, waxing, sugaring, threading remove the entire hair from the root, the results lasting several days to several weeks.

Permanent hair removal uses chemicals, energy of various types, or a combination to target the cells that cause hair growth. Laser hair removal is an effective method of hair removal on hairs that have color. Laser cannot treat white hair. The laser targets the melanin color in the lower 1/3 of the hair follicle, which is the target zone. Electrolysis (electrology) uses electrical current, and/or localized heating. 

Medication to reduce production of hair is currently under testing. One medicinal option suppresses testosterone by increasing the sex hormone-binding globulin.[28] Another controls the overproduction of hair through the regulation of a luteinizing hormone.

Resources

  • NIH