Three Successive Generations: DISCUSSION

1 Oct
2009

Three Successive Generations DISCUSSION

The most common type of ectodermal dysplasia is the anhidrotic/hypohidrotic type, known as Christ-Siemens-Touraine syndrome, in which there is a triad of dentition anomalies, partial or complete absence of the sweat glands, and hypotrichosis. First described by Thurman, the typical facies is characterized by frontal bossing, sparse, hypopig-mented hair, malar/midfacial hypoplasia, thick everted lips, a flattened (saddle) nasal bridge and prominent low-set ears. The skin is often finely wrinkled and hyperpigmented around the eyes, and the teeth are often peg-shaped and partially absent.

The less common Clouston syndrome, or hidrot-ic-type ectodermal dysplasia, is characterized as autosomal dominant and usually involves dystrophic or hypoplastic nails, hypotrichosis and hyperkeratosis of the palms and soles as the most frequent findings. Unlike the anhidrotic forms, sweating is usually normal, and dentition is less often affected, although small teeth and an increased prevalence for dental caries have been noted in some patients. Viagra Super Active

Both the anhidrotic/hypohidrotic types and the hidrotic types of ectodermal dysplasias are usually associated with normal cognitive development and intellectual functioning, normal growth and development. No study has shown any deficit in neuroec-todermal-cell-derived organs, such as the adrenal glands. Fertility has not been shown to be affected, and most of these patients have a normal life expectancy. Life-threatening hyperthermia, especially in children with anhidrotic ectodermal dysplasia not only can cause mild mental deficiency occasionally but is also a major cause of death. Patients with AED should be advised to live in a cool climate and have ready access to water to avoid overheating.

Recent advances in genomic research have allowed for the characterization of many of the complex molecular pathways involved in ectodermal differentiation and identification of many genes involved in the various ectodermal dysplasias, especially the EDA1 gene. A recent study in mice has shown that administration of recombinant EDA1 protein to the pregnant mother can correct the defect in the offspring and induce sweat gland development. AED associated with immunodeficiency is a newly recognized primary immunodeficiency caused by mutations in the NEMO gene, which encodes for a protein that plays an important role in human development, skin homoeostasis and immunity. cialis super active online

The anhidrotic/hypohidrotic form of ectodermal dysplasia has most often been characterized as an X-linked recessive trait (Xql2-ql3). However, rare cases of autosomal recessive and autosomal dominant inheritance have been reported, mapped to the chromosome 2ql l-ql3 region. Our three patients were a mother, daughter and granddaughter who all had the characteristic frontal bossing with midface hypoplasia, hypodontia and an absence of hair and sweat glands. Further studies may elicit whether patients with autosomal dominant AED demonstrate any variability in the pattern of expression or penetrance throughout successive generations.

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