Ankyloblepharon-ectodermal Defects-cleft Lip-palate Syndrome Due to a Novel Missense Mutation in the SAM Domain of the TP63 Gene.

Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare genetic disease with an autosomal dominant transmission, characterized by several congenital anomalies. Clinical features include ectodermal defects affecting the skin, hair, teeth, nails and sweat glands, associated with typical eyelid fusion in addition to a cleft lip and/or palate. The diagnosis is based on clinical criteria and molecular genetic testing of TP63 gene, the gene related to AEC syndrome. In this context, most reported mutations induce an amino acid change in the sterile alpha motif (SAM) domain, and are predicted to disrupt protein-protein interactions. We here describe the case of a 2-year-old Moroccan girl diagnosed with AEC syndrome on the basis of clinical features. The molecular studies and bioinformatics tools revealed a novel heterozygous missense mutation c.1798G>C (p.Gly600Arg) in exon 14 of the TP63 gene, that was not found in her parents. The molecular analysis and the early diagnosis of this syndrome are important to offer appropriate genetic counseling and management to patients and their families.

Autosomal dominant anhidrotic ectodermal dysplasias at the EDARADD locus.

Anhidrotic ectodermal dysplasia (EDA) is a disorder of ectodermal differentiation characterized by sparse hair, abnormal or missing teeth, and inability to sweat. X-linked EDA is the most common form, caused by mutations in the EDA gene, which encodes ectodysplasin, a member of the tumor necrosis factor (TNF) family. Autosomal dominant and recessive forms of EDA have been also described and are accounted for by two genes. Mutations in EDAR, encoding a TNF receptor (EDAR) cause both dominant and recessive forms. In addition, mutations in a recently identified gene, EDARADD, encoding EDAR-associated death domain (EDARADD) have been shown to cause autosomal recessive EDA. Here, we report a large Moroccan family with an autosomal dominant EDA. We mapped the disease gene to chromosome 1q42.2-q43, and identified a novel missense mutation in the EDARADD gene (c.335T>G, p.Leu112Arg). Thus, the EDARADD gene accounts for both recessive and dominant EDA. EDAR is activated by its ligand, ectodysplasin, and uses EDARADD to build an intracellular complex and activate nuclear factor kappa B (NF-kB). We compared the functional consequences of the dominant (p.Leu112Arg) and recessive mutation (p.Glu142Lys), which both occurred in the death domain (DD) of EDARADD. We demonstrated that the p.Leu112Arg mutation completely abrogated NF-kB activation, whereas the p.Glu142Lys retained the ability to significantly activate the NF-kB pathway. The p.Leu112Arg mutation is probably a dominant negative form as its cotransfection impaired the wild-type EDARADD's ability to activate NF-kB. Our results confirm that NF-kB activation is impaired in EDA and support the role of EDARADD DD as a downstream effector of EDAR signaling.

Inhabitual autosomal recessive form of dentin dysplasia type I in a large consanguineous Moroccan family.

Dentin dysplasia is a rare autosomal dominant genetic disease characterized by defect of dentin development and the causal gene is DSPP (Dentin Sialophosphoprotein gene). We report in the present study a large Moroccan family in which dentin dysplasia is clearly transmitted as an autosomal recessive trait. Four males and females family members born from healthy consanguineous parents are carriers of the typical features of the dentin dysplasia type I. Polymorphic markers that span the DSPP gene, allowed us to show that this locus is not linked to dentin dysplasia in our family. We also excluded in our family the SMOC2 gene (Sparc Related Modular Calcium Binding Protein 2) which was recently identified as a causal gene in dentin dysplasia type I with microdontia and misshapen teeth. This family represents, a new description of autosomal recessive pattern of inheritance of dentin dysplasia type I. Moreover, this form of dentin dysplasia is not allelic to the autosomal dominant dentin dysplasia and the genetic cause is to be discovered.

[Incontinentia pigmenti: a case study]. / Incontinentia pigmenti: à propos d'un cas.

Incontinentia pigmenti is a rare hereditary, dominant, X-linked disorder. It involves the skin, the teeth, the eyes and the central nervous system. The case we report is an infant girl aged 2 months. She had typical skin lesions associated with severe impairment of her left eye. We comment on the clinical, histological, genetic, and therapeutic characteristics of this rare disease. Ophthalmologic examination should be made early in order to diagnose ocular involvement at an early stage of the disease to provide for greater treatment possibilities.