Adermatoglyphia (adermatoglyphia) - Gen SMARCAD1.
The adermatoglyphia is a disorder characterized by the absence of fingerprints on the fingertips and toes and on the palms of hands and soles of the feet. In some families, this alteration occurs without other signs and symptoms related. In others, a lack of dermatoglyphs associated with other features as small white bumps on the face called milia, skin blisters in areas exposed to heat or friction, and a small number of sweat glands in the hands and feet. The adermatoglyphia is also a feature of several rare syndromes classified as ectodermal dysplasias, Naegeli-Franceschetti including Jadassohn syndrome or-Dermatopathia pigmentosa reticularis affecting the skin, hair, sweat glands and teeth.
This process is due to mutations in the gene SMARCAD1, located on the long arm of chromosome 4 (4q22.3). This gene encodes two isoforms of the protein SMARCAD1: an isoform of the full length and a shorter, specific isoform skin. The full length isoform is expressed in multiple tissues, where it regulates the activity of a wide variety of genes involved in maintaining stability of cellular genetic information. The specific isoform of the skin is expressed only in skin cells and although little is known about its function, seems to play a critical role in the formation of dermatoglyphs. Isoform is likely to be one of the factors that determine the pattern of unique fingerprint of each person.
They have identified at least 4 mutations in the gene responsible for adermatoglyphia SMARCAD1. These mutations affect the specific isoform skin SMARCAD1 protein but not full - length isoform. These genetic changes inhibit the coding of any specific isoform of functional skin from a copy of the gene, which reduces the total amount of this protein in skin cells. Although it is unclear how these genetic changes lead to adermatoglyphia, it is likely that deficiency of the specific version of the skin of the SMARCAD1 protein affects signaling pathways necessary for the development and normal function of the skin, including the formation of dermatoglyphs.
This disease is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell SMARCAD1 is sufficient for the disease to be expressed. In many cases, an affected person has a parent with the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with adermatoglyphia, by complete PCR amplification of exons SMARCAD1 gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).