X-linked and autosomal recessive Hypohidrotic Ectodermal Dysplasia: genotypic-dental phenotypic findings.

Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of ectodermal structures and its molecular etiology corresponds to mutations of EDA-EDAR genes. The aim of this study was first to investigate the genotype and dental phenotype associated with HED and second, to explore possible correlations between dental features and molecular defects. A total of 27 patients from 24 unrelated families exhibiting clinical signs of HED (22 XLHED males, 5 autosomal recessive forms) were retrospectively included. In the sample, 25 different mutations on EDA and EDAR genes were detected; 10 were not previously described. EDA and EDAR mutations corresponded respectively to 80.0% and 20.0% of the mutations. The dental phenotype analysis revealed a mean number of primary and permanent missing teeth ranging respectively from 14.5 (4-20) to 22.5 (10-28); the majority of the patients exhibited dysmorphic teeth. Overall, no differential expression in the degree of oligodontia according to either the mutated gene, the mutated functional sub-domains, or the mutation type, could be observed. Nevertheless, the furin group exhibited severe phenotypes unobserved in the TNF group. Significant differences in the number of some primary missing teeth (incisor and canine) related to EDA-EDAR genes defects were detected for the first time between XLHED and autosomal recessive HED, suggesting differential local effects of EDA-EDAR genes during odontogenesis. The present genotypic-phenotypic findings may add to the knowledge of the consequences of the molecular dysfunction of EDA-NF-kB in odontogenesis, and could be helpful in genetic counseling to distinguish autosomal forms from other HED syndromes.

Clinical, molecular, and genotype-phenotype correlation studies from 25 cases of oral-facial-digital syndrome type 1: a French and Belgian collaborative study.

Oral-facial-digital syndrome type 1 (OFD1) is characterised by an X linked dominant mode of inheritance with lethality in males. Clinical features include facial dysmorphism with oral, tooth, and distal abnormalities, polycystic kidney disease, and central nervous system malformations. Large interfamilial and intrafamilial clinical variability has been widely reported, and 18 distinct mutations have been previously reported within OFD1. A French and Belgian collaborative study collected 25 cases from 16 families. OFD1 was analysed using direct sequencing and phenotype-genotype correlation was performed using chi2 test. X inactivation studies were performed on blood lymphocytes. In 11 families, 11 novel mutations, including nine frameshift, one nonsense, and one missense mutation were identified, which spanned nine different exons. A combination of our results with previously reported cases showed that the majority of mutations (65.5%) was located in exons 3, 8, 9, 13, and 16. There was phenotype-genotype correlation between (a) polycystic kidney disease and splice mutations; (b) mental retardation and mutations located in exons 3, 8, 9, 13, and 16; and (c) tooth abnormalities and mutations located in coiled coil domains. Comparing the phenotype of the families with a pathogenic mutation to families with absence of OFD1 mutation, polycystic kidneys and short stature were significantly more frequent in the group with no OFD1 mutation, whereas lingual hamartomas were significantly more frequent in the group with OFD1 mutation. Finally, an X inactivation study showed non-random X inactivation in a third of the samples. Differential X inactivation between mothers and daughters in two families with high intrafamilial variability was of particular interest. Slight phenotype-genotype correlations were established, and X inactivation study showed that skewed X inactivation could be partially involved in the pathogenesis of intrafamilial clinical variability.

Oligodontia, microcephaly and facial dysmorphia syndrome.

Congenital absence of third molars is common. However absence of the other permanent teeth is relatively rare. Absence of teeth may be isolated or associated to other features. We had the opportunity to examine a girl with oligodontia associated to microcephaly, to facial dysmorphia and to short stature.

Arthrogryposis, ectodermal dysplasia and other anomalies in two sisters.

Ectodermal dysplasia with arthrogryposis is an uncommon condition. We describe two daughters of a distant consanguineous couple with oligodentia, enamel abnormalities, camptodactyly, longitudinally broken nails, growth retardation, joint contractures with amyotrophy, hypohidrotic skin with tendency to excessive bruising and scarring after injuries and scratching, kypho-scoliosis, mild facial dysmorphia and microcephaly. The condition is probably due to an autosomal recessive gene, the parents being gypsies of the same ancestral origin.

Wiedemann-Rautenstrauch syndrome. A case report and review of the literature.

In 1977 Rautenstrauch and Snigula reported on two sisters with a previously undescribed, progeria-like syndrome. Two years later Wiedemann described two unrelated males with the same condition. Since than only a few published cases appeared in the literature. We had the opportunity to study a boy affected by this extremely rare condition. This boy was born after intrauterine growth retardation. At birth two natal teeth were present. OFC was normal despite apparent macrocephaly. During infancy a progeroid appearance was noted with sparse hair, prominent scalp veins, greatly widened anterior fontanelles, malar hypoplasia, and generalized lipoatrophy. The face was triangular with a small maxilla and a protuding chin, the eyes were low-set, the eyebrows and eyelashes were scanty. At the age of 3.5 years there was striking general deficiency of subcutaneous fatty tissue apart from accumulation of adipose tissue on the buttocks and flanks, growth was retarded, mental development was at the low borderline of normal. Cholesterolemia was at the upper range of normal, there was an increase of triglycerides: 3.31 mmol/L (Normal < 1 mmol/L). Other progeroid syndromes such as Hutchinson-Guilford, Berardinelli-Seip, De Barsy, leprechaunism, Cockayne and Hallerman-Streiff could be excluded as well as the CDG syndrome. This condition is most probably inherited as an autosomal recessive trait.

Binder syndrome in a mother and her son.

Binder syndrome or maxillonasal dysplasia is characterized by maxillary hypoplasia and a flat, vertical nose. Inheritance is uncertain. We report on a mother and her son with Binder syndrome. The proband was the last child of a kinship of seven children. Three sisters, three brothers and the parents were normal. The proband had a maxillary hypoplasia and a flat, vertical nose. The columella was short, the nostrils had a triangular shape and the upper lip was convex with an acute nasolabial angle. There were no dental abnormalities apart from those secondary to malocclusion. Height and intelligence were normal. After an uncomplicated pregnancy, the proband delivered a boy who had low nasal bridge, hypertelorism, maxillary hypoplasia and a small nose with a broad columella. Although the majority of cases of maxillonasal dysplasia are sporadic, familial occurrence has been reported by a number of authors. In six pedigrees the recurrence was in second or third degree relatives. Recurrence in sibs with unaffected parents has been observed seven times and an affected parent and child has been rarely reported. The Binder phenotype may be heterogeneous. The pattern of abnormalities seen in this condition does not represent a causally defined entity.

Mental retardation, ataxia, seizures, dysmorphia, and hydrocephaly in two sibs. Angelman syndrome or new syndrome.

We report two sibs with Angelman syndrome or an apparently new syndrome. In addition to severe mental retardation and seizures, clinical examination showed an ataxic and stiff legged gait, truncal hypotonia with hypertonia of the limbs, dysmorphic facial features (brachycephaly, large mouth, pointed chin and a prominent jaws) and scoliosis. Brain CT scan and MRI revealed ventricular enlargement and squared frontal horns. Pregnancy and delivery were uneventful. Karyotypes were normal. No deletion of chromosome 15q11-13 region was shown by molecular genetic techniques. The parents who are normal are second cousins. The condition is therefore probably inherited as an autosomal recessive one.

Dento-craniofacial phenotypes and underlying molecular mechanisms in hypohidrotic ectodermal dysplasia (HED): a review.

The hypohidrotic ectodermal dysplasias (HED) belong to a large and heterogeneous nosological group of polymalfomative syndromes characterized by dystrophy or agenesis of ectodermal derivatives. Molecular etiologies of HED consist of mutations of the genes involved in the Ectodysplasin (EDA)-NF-kappaB pathway. Besides the classic ectodermal signs, craniofacial and bone manifestations are associated with the phenotypic spectrum of HED. The dental phenotype of HED consists of various degrees of oligodontia with other dental abnormalities, and these are important in the early diagnosis and identification of persons with HED. Phenotypic dental markers of heterozygous females for EDA gene mutation-moderate oligodontia, conical incisors, and delayed dental eruption-are important for individuals giving reliable genetic counseling. Some dental ageneses observed in HED are also encountered in non-syndromic oligodontia. These clinical similarities may reflect possible interactions between homeobox genes implicated in early steps of odontogenesis and the Ectodysplasin (EDA)-NF-kappaB pathway. Craniofacial dysmorphologies and bone structural anomalies are also associated with the phenotypic spectrum of persons with HED patients. The corresponding molecular mechanisms involve altered interactions between the EDA-NF-kappaB pathway and signaling molecules essential in skeletogenic neural crest cell differentiation, migration, and osteoclastic differentiation. Regarding oral treatment of persons with HED, implant-supported prostheses are used with a relatively high implant survival rate. Recently, groundbreaking experimental approaches with recombinant EDA or transgenesis of EDA-A1 were developed from the perspective of systemic treatment and appear very promising. All these clinical observations and molecular data allow for the specification of the craniofacial phenotypic spectrum in HED and provide a better understanding of the mechanisms involved in the pathogenesis of this syndrome.

Two cousins with partial trisomy 12q and monosomy 12p recombinants of a familial pericentric inversion of the chromosome 12.

Partial trisomy 12q and monosomy 12p lead to multiple malformation syndromes. Instead of trisomy 12q that has been reported as a clinically identifiable syndrome, monosomy 12p is characterized by a wide phenotypic spectrum. We report two cousins suffering from severe mental retardation, seizures, and dysmorphic features related to a trisomy 12q24.3-->qter and a monosomy 12p13-->pter resulting from a familial pericentric inversion of chromosome 12. In an attempt to improve the clinical delineation of these two syndromes, we compared our two patients with previous reports of these aneusomies. This review emphasizes the high frequency of familial translocations, including a breakpoint at 12q24 involved in trisomy 12q whereas monosomy 12p occurs most frequently de novo. Despite the poor specificity of the signs, this comparison allowed us to determine the clinical features present in more than 20% of patients with trisomy 12q or monosomy 12p. We particularly emphasize some consistent leading features of monosomy 12p, including microcephaly, dental, cardio-vascular, extremity, and sensorial abnormalities, initially not reported as recurrent in this syndrome.