Craniofrontonasal dysplasia X - linked (Craniofrontonasal syndrome, X-linked) - Gen EFNB1.
The craniofrontonasal dysplasia linked to X is a rare disorder characterized by craniofacial abnormalities present area, grooved nails, mental deficiency and various abnormalities of soft tissues and skeletal.
Generally, this disease presents an improper characteristic of an X - linked disorder and affects more women than men. Most men are affected mild form (only hipertelorismo). Meanwhile, women have Frontonasal dysplasia, coronal craniosynostosis with brachycephaly and bossing the center of the forehead. Other signs and symptoms may include skeletal malformations as slumped shoulders with dysplastic clavicles, fat toes thickened, short thumbs, brachydactyly, clinodactilia, gaps between the first and second toes of the feet, long fingers and toes, syndactyly, polydactyly , camptodactilia, scoliosis and hyperextensible joints. In addition, individuals with craniofrontonasal dysplasia linked to X may have facial abnormalities including microcephaly, facial asymmetry, palpebral fissures, dry hair and extremely curly, back line of low hair, wide neck, high arched palate, cleft lip and palate, malocclusion, abnormal auditory ossicles and sensorineural deafness. Some individuals diaphragm hernia, pectus excavatum, shawl scrotum, hypospadias and hypogenesis callosum.
This disease is due to mutations in the gene EFNB1, located on the long arm of the X chromosome (Xq12). This gene encodes ephrin B1, a membrane protein of type I and a ligand of receptor tyrosine kinases related-Ef. This protein may play a role in cell adhesion and function in the development or maintenance of the nervous system.
They have identified at least 33 mutations in the gene EFNB1 in people with X - linked craniofrontonasal dysplasia Approximately 20% of all cases of the disease do not have an identified mutation in the gene EFNB1. It is believed that these cases may be due to misdiagnosis, large deletions or rearrangements undetected, or mutations outside the coding region EFNB1, mosaicism, or additional CFNS loci. It is believed that in some women whose reason for the disease is due to heterozygous mutations in the gene exists EFNB1 cell interference that causes the disease is more severe than in men.
This disease is transmitted inheritance pattern linked to X. The X - linked inheritance means that in males, an altered copy of the gene in each cell is sufficient to cause disease. In women, a mutation must be present in both copies of the gene result in the alteration. In general, males are affected by X - linked far more often than women alterations. However, X - linked craniofrontonasal dysplasia presents an improper characteristic of an X - linked disorder, is that mostly affects women than men. The probability that an affected woman passing the disease to her child is 50%. An affected male will transmit the disease to their daughters but none of their children.
Tests in IVAMI: in IVAMI perform detection of mutations associated with X - linked craniofrontonasal dysplasia, by complete PCR amplification of exons EFNB1 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).