Instituto Valenciano de Microbiología

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
CIF B-96337217


Naegeli-Franceschetti-Jadassohn syndrome ... dermatopathia reticular pigmentosa (Naegeli-Franceschetti-Jadassohn syndrome, Dermatopathia pigmentosa reticularis) - Gen KRT14.

The Naegeli-Franceschetti-Jadassohn syndrome pigmentosa reticularis / pigmentosa Dermatopathia reticularis (NFJS / DPR) is a rare type of ectodermal dysplasia, a group of processes characterized by abnormal development of ectodermal tissues including skin glands, hair, nails , teeth, and sweat. NFJS and DPR were originally described as separate alterations; however, because they have similar characteristics and are due to mutations in the same gene, often they considered the same disease.

The most common signs of NFJS / DPR include reticulated hyperpigmentation, which appears in infancy or early childhood and can disappear with age or persist throughout life; palmoplantar keratoderma; blisters on the palms of hands and soles of the feet; misshapen, brittle and thin nails or thicker than usual and dermatoglyphs loss. Additional features of NFJS / DPR may include hipohidrosis or hyperhidrosis and dental anomalies. In addition, some affected individuals manifest non-scarring alopecia on the scalp, eyebrows and underarms.

This process is due to mutations in the gene KRT14, located on the long arm of chromosome 17 (17q21.2). This gene encodes the protein keratin 14. The keratins are a group of hard, fibrous proteins that form the structural framework of certain cells, especially cells which form the skin, hair and nails. Keratin 14 occurs specifically in keratinocytes of the epidermis. Keratin 14 is attached to a similar protein, keratin 5, encoded from KRT5 gene, to form keratin intermediate filaments. These filaments are assembled into strong networks that help set the keratinocytes together and anchor the epidermis of the underlying layers of the skin. The network of keratin intermediate filaments provide strength and elasticity to the skin and protects it from being damaged by friction and other everyday physical stresses. In addition, it is likely that keratin 14 can also play a role in the formation of sweat glands and the development of the rete ridges of the hands and feet.

They have identified several mutations in the gene responsible KRT14 Naegeli-Franceschetti-of Jadassohn / reticular dermatopathia pigmentosa (NFJS / DPR) syndrome. These genetic changes reduce the amount of functional keratin 14 in keratinocytes. Deficiency of this protein makes these cells more prone to apoptosis. The resulting loss of keratinocytes alters the normal development and tissue structure of the ectoderm, which probably underlies most of the problems of the skin and nails characteristic NFJS / DPR. However, it is unclear how a deficiency of keratin 14 is related to the reticulated hyperpigmentation which is also a characteristic of this disease.

This disease is inherited as an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient for the disease to be expressed. In most cases, an affected person has a parent with the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with Naegeli-Franceschetti-of Jadassohn / reticular dermatopathia pigmentosa (NFJS / DPR) syndrome by complete PCR amplification of the exons of the gene KRT14, 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).