Siulan Vendramini-Pittoli

Oculoauriculovertebral spectrum: report of nine familial cases with evidence of autosomal dominant inheritance and review of the literature.

Oculoauriculovertebral spectrum (OAVS; OMIM 164210) is a complex condition characterized by defects of aural, oral, mandibular and vertebral development. The aetiology of this condition is likely to be heterogeneous; most cases are sporadic, however, familial cases suggesting autosomal recessive and autosomal dominant inheritance have been reported. In this study, we describe the clinical aspects of nine familial cases with evidence of autosomal dominant inheritance and compare them with reports in the literature. Interfamilial and intrafamilial clinical variabilities were observed in this study (reinforcing the necessity of careful examination of familial members). We suggest that oculoauriculovertebral spectrum with autosomal dominant inheritance is characterized mainly by bilateral auricular involvement and rarely presents extracranial anomalies.

Mutations in Endothelin 1 Cause Recessive Auriculocondylar Syndrome and Dominant Isolated Question-Mark Ears

Auriculocondylar syndrome (ACS) is a rare craniofacial disorder with mandibular hypoplasia and question-mark ears (QMEs) as major features. QMEs, consisting of a specific defect at the lobe-helix junction, can also occur as an isolated anomaly. Studies in animal models have indicated the essential role of endothelin 1 (EDN1) signaling through the endothelin receptor type A (EDNRA) in patterning the mandibular portion of the first pharyngeal arch. Mutations in the genes coding for phospholipase C, beta 4 (PLCB4) and guanine nucleotide binding protein (G protein), alpha inhibiting activity polypeptide 3 (GNAI3), predicted to function as signal transducers downstream of EDNRA, have recently been reported in ACS. By whole-exome sequencing (WES), we identified a homozygous substitution in a furin cleavage site of the EDN1 proprotein in ACS-affected siblings born to consanguineous parents. WES of two cases with vertical transmission of isolated QMEs revealed a stop mutation in EDN1 in one family and a missense substitution of a highly conserved residue in the mature EDN1 peptide in the other. Targeted sequencing of EDN1 in an ACS individual with related parents identified a fourth, homozygous mutation falling close to the site of cleavage by endothelin-converting enzyme. The different modes of inheritance suggest that the degree of residual EDN1 activity differs depending on the mutation. These findings provide further support for the hypothesis that ACS and QMEs are uniquely caused by disruption of the EDN1-EDNRA signaling pathway.

Analysis of MLL2 gene in the first Brazilian family with Kabuki syndrome

Most patients with Kabuki syndrome (KS) are the only person in their family with the condition. However, familial cases of KS have been described showing evidence that this syndrome can be inherited as a dominant trait with variable expressivity. We report on two related individuals with facial findings characteristic of KS. The proposita had arched eyebrows, long and upward slanting palpebral fissures, cleft lip and palate, retromicrognathia, brachydactyly of hands and feet, stubby fingers, nail hypoplasia, and prominent finger pads. Her mother had eyebrows with dispersed lateral half, long and upward slanting palpebral fissures, retrognathia, abnormal and posteriorly rotated ears, prominent finger pads, brachydactyly of feet, learning difficulties, and psychomotor development delay. DNA sequencing revealed a novel missense mutation in the MLL2 gene in both the proposita and her mother. The mutation (p.R5432Q) was found in the exon 51, within the SET domain of the gene, which confers methyltransferase activity on the protein. Therefore, the epigenetic and transcriptional regulatory properties of this protein may be altered and this suggests that the mutation is the cause of phenotype observed in both the patient and her mother. The clinical signs and the molecular evidence in this family further support the notion that KS is an autosomal dominant condition with variable expressivity. To our knowledge this is the first report of a Brazilian family with recurrence of this syndrome.

Mandibulofacial Syndrome With Growth and Mental Retardation, Microcephaly, Ear Anomalies With Skin Tags, and Cleft Palate in a Mother and Her Son: Autosomal Dominant or X-Linked Syndrome?

We report on a Brazilian mother and her son affected with mandibulofacial dysostosis, growth and mental retardation, microcephaly, first branchial arch anomalies, and cleft palate. To date only three males and one female, all sporadic cases, with a similar condition have been reported. This article describes the first familial case with this rare condition indicating autosomal dominant or X‐linked inheritance.

Auriculo-condylar syndrome. Confronting a diagnostic challenge.

Auriculo‐condylar syndrome (ACS) is characterized by typical ears malformation (so‐called “question mark” ears), prominent cheeks, microstomia, and abnormality of the temporomandibular joint and condyle of the mandible. In this report we describe a new simplex case and a previously unreported family with affected individuals in three generations documenting clinical variability. Linkage study for markers located in candidate region for ACS1 (1p21.1–q23.3) was excluded in our familial case, reinforcing the hypothesis of genetic heterogeneity for this condition. A review of the literature focusing diagnostic criteria and features of ACS was performed.

Novel variants in GNAI3 associated with auriculocondylar syndrome strengthen a common dominant negative effect.

Auriculocondylar syndrome is a rare craniofacial disorder comprising core features of micrognathia, condyle dysplasia and question mark ear. Causative variants have been identified in PLCB4, GNAI3 and EDN1, which are predicted to function within the EDN1–EDNRA pathway during early pharyngeal arch patterning. To date, two GNAI3 variants in three families have been reported. Here we report three novel GNAI3 variants, one segregating with affected members in a family previously linked to 1p21.1-q23.3 and two de novo variants in simplex cases. Two variants occur in known functional motifs, the G1 and G4 boxes, and the third variant is one amino acid outside of the G1 box. Structural modeling shows that all five altered GNAI3 residues identified to date cluster in a region involved in GDP/GTP binding. We hypothesize that all GNAI3 variants lead to dominant negative effects.

Interstitial 1q21.1 Microdeletion Is Associated with Severe Skeletal Anomalies, Dysmorphic Face and Moderate Intellectual Disability

We report on a Brazilian patient with a 1.7-Mb interstitial microdeletion in chromosome 1q21.1. The phenotypic characteristics include microcephaly, a peculiar facial gestalt, cleft lip/palate, and multiple skeletal anomalies represented by malformed phalanges, scoliosis, abnormal modeling of vertebral bodies, hip dislocation, abnormal acetabula, feet anomalies, and delayed neuropsychological development. Deletions reported in this region are clinically heterogeneous, ranging from subtle phenotypic manifestations to severe congenital heart defects and/or neurodevelopmental findings. A few genes within the deleted region are associated with congenital anomalies, mainly the RBM8A, DUF1220, and HYDIN2 paralogs. Our patient presents with a spectrum of unusual malformations of 1q21.1 deletion syndrome not reported up to date.

Variants in members of the cadherin-catenin complex, CDH1 and CTNND1, cause blepharocheilodontic syndrome

Blepharocheilodontic syndrome (BCDS) consists of lagophthalmia, ectropion of the lower eyelids, distichiasis, euryblepharon, cleft lip/palate and dental anomalies and has autosomal dominant inheritance with variable expression. We identified heterozygous variants in two genes of the cadherin–catenin complex, CDH1, encoding E-cadherin, and CTNND1, encoding p120 catenin delta1 in 15 of 17 BCDS index patients, as was recently described in a different publication. CDH1 plays an essential role in epithelial cell adherence; CTNND1 binds to CDH1 and controls the stability of the complex. Functional experiments in zebrafish and human cells showed that the CDH1 variants impair the cell adhesion function of the cadherin–catenin complex in a dominant-negative manner. Variants in CDH1 have been linked to familial hereditary diffuse gastric cancer and invasive lobular breast cancer; however, no cases of gastric or breast cancer have been reported in our BCDS cases. Functional experiments reported here indicated the BCDS variants comprise a distinct class of CDH1 variants. Altogether, we identified the genetic cause of BCDS enabling DNA diagnostics and counseling, in addition we describe a novel class of dominant negative CDH1 variants.

Multisystem Involvement in a Patient with a PTCH1 Mutation: Clinical and Imaging Findings

In this article, we report on a Brazilian female patient born to consanguineous parents and presenting with alobar holoprosencephaly, severe eye involvement, and unusual skin hyperpigmented lesions. She was found to have a mutation (c.2240T > C; p.Val751Gly) in exon 15 of the PTCH1 gene. Mutations in this gene are associated with the nevoid basal cell carcinoma syndrome (NBCCS, OMIM 109400) and, in other instances, with holoprosencephaly (holoprosencephaly-7, OMIM 610828). Severe eye involvement ranging from orbital coloboma to microphthalmia has been seldom reported in patients with NBCCS with PTCH1 mutations. To our knowledge, this is the first report of an individual with central nervous system, skin, and eye manifestations due to a PTCH1 mutation. Mechanisms involved in these multisystem manifestations are discussed.

Mandibulofacial dysostosis Bauru type: Refining the phenotype

Mandibulofacial dysostosis (MFD) Bauru type (OMIM 604830) is a rare genetic condition characterized mainly by malar hypoplasia, orofacial cleft, and micrognathia. Here, we describe the clinical and radiographic sings of 13 individuals (12 female and 1 male) from eight unrelated kindreds with MFD Bauru type, including four previously reported cases, treated at the Hospital for Rehabilitation of Craniofacial Anomalies. The clinical phenotype was characterized by severe underdevelopment of mandible, midface hypoplasia, orofacial cleft, bitemporal narrowing, mild upper eyelid down slanting, high nasal bridge, thick and everted lower lip, minor ears abnormalities, and hearing loss. Radiographic aspects included downslanting of zygomatic arch, maxillary hypoplasia, microretrognathia, hypoplastic mandibular condyles, and ectopic external auditory canal. Recurrence was observed in two of eight families and the affected distribution pattern was compatible with autosomal dominant inheritance in one and autosomal recessive in another, indicating possible genetic heterogeneity for this condition. Clinical and radiographic findings in this report contribute to the delineation of this rare MFD.