Erythrokeratodermia with ataxia (EKDA) is a hereditary disorder of the skin and nervous system (neurocutaneous syndrome) characterized by groups of hard, red plaques that develop during infancy and childhood. When these skin lesions heal, the disorder seems to become dormant for several years, after which the neurological symptoms and signs emerge in the form of a typically awkward gait (ataxia) when the affected individual is around 40 years of age or older.
Many researchers active in the study of the family of diseases known as the ichthyoses consider EKDA to be a variant of an ichthyotic disorder, erythrokeratodermia variabilis (EKDV). However, there is no general consensus on this at this time.
Erythrokeratodermia with ataxia starts during early infancy. This disorder is characterized by groups of red, hardened scaly skin plaques (ichthyosis) that remain throughout childhood, but disappear during young adulthood. These plaques tend to develop most often on the skin of the extremities. They usually disappear during the summer. A progressive neurologic syndrome develops during adulthood, consisting of impaired muscle coordination (ataxia), imperfect articulation of speech (dysarthria), involuntary rhythmic oscillation of the eyes (nystagmus), and decreased tendon reflexes.
Erythrokeratodermia with ataxia is thought to be inherited as an autosomal dominant genetic trait.
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 11p13” refers to band 13 on the short arm of chromosome 11. 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 that 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.
All individuals carry a few abnormal genes. Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.
Erythrokeratodermia with ataxia is an extremely rare disorder that is thought to affect males and females in equal numbers.
The diagnosis of erythrokeratodermia with ataxia may be suspected soon after birth by the appearance of characteristic skin lesions. Neurological abnormalities associated with this disorder may not occur until adulthood.
Treatment is aimed at reducing thickening and cracking of the skin. It may include 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 this disorder.
The treatment of erythrokeratodermia with ataxia is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists, including dermatologists, neurologists and other healthcare professionals, to systematically and comprehensively plan an affected child's treatment. Genetic counseling may be helpful for affected individuals and their families.
If the symptoms of ataxia appear in adulthood, the services of orthopedic surgeons, rehabilitation specialists, and others may be required.
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Richard G, Brown N, Rouan F, et al. Genetic heterogeneity in erythrokeratodermia variabilis: Novel mutations in the connexin gene GJB4 (Cx30.3) and genotype-phenotype correlations. J Invest Dermatol. 2003;120:601-09.
Richard G, Brown N, Smith LE, et al. The spectrum of mutations in erythrokeratodermia[s] – novel and de novomutations in GJB3. Hum Genet. 2000;106:321-29.
FROM THE INTERNET
McKusick VA, ed. Online Mendelian Inheritance In Man (OMIM). The Johns Hopkins University. Erythrokeratodermia with Ataxia. Entry Number; 133190: Last Edit Date; 3/18/2004.
Erythrokeratodermia Variabilis. FIRST: Foundation for Ichthyosis & Related Skin Types. 2004.
The National Registry for Ichthyosis and Related Disorders. University of Washington. nd.
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