[Primary failure of eruption (PFE). Clinical and molecular genetics analysis]. / Défaut primaire d'éruption (DPE). Analyse génétique clinique et moléculaire∗

BACKGROUND: The term "primary failure of eruption" (PFE) refers to the complete or partial failure of a primary non-ankylosed tooth to erupt due to a disturbance of the eruption mechanism. Up to now, the molecular basis for this failure was unknown. PATIENTS AND METHODS: Four families were studied in whom at least two members were affected by non-syndromic PFE as part of a clinical and molecular genetics study. Radiological diagnostics (OPTs) were carried out in all patients and their unaffected relatives (control group). The genetic analysis included a genomewide linkage analysis followed by direct DNA sequencing of positional candidate genes. RESULTS: Starting from the index patients, we were able to reconstruct pedigrees over two and/or three generations in the families that indicated an autosomal-dominant mode of inheritance of non-syndromic PFE. Fifteen patients were diagnosed with PFE. Gender distribution was nearly equal (7 female, 8 male). Molecular genetic analysis of the PTHR1 gene revealed three distinct heterozygous mutations (c.1050-3C>G; c.543 + 1G>A; c.463G>T). Unaffected persons exhibited no mutations. CONCLUSION: Knowledge of the genetic causes of non-syndromic PFE can now be used for the differential diagnosis of eruption failure. It permits affected family members to be identified early and may lead to new treatment possibilities in the long term. The genetically-verified diagnosis of "primary failure of eruption" can protect patients and orthodontists from years of futile treatment, because orthodontic treatment alone does not lead to success. Moreover, it has a negative influence on unaffected teeth and areas of the jaw.

Anti-Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) differentially regulate apoptosis in normal and neoplastic human basophils.

Basophilia is associated with allergic and parasitic diseases and advanced chronic myeloid leukemia. In the present study, we characterized the expression and function of the death receptors Fas/CD95 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors in basophils from healthy donors compared to neoplastic basophils. Peripheral blood basophils obtained from healthy donors (HD-PBB) and from patients with chronic myeloid leukemia (CML-PBB) were found to express high levels of Fas/CD95 and low levels of TRAIL-R2, whereas the basophil-like chronic myeloid leukemia cell line KU-812 expressed significant levels of TRAIL-R1 and TRAIL-R2. HD-PBB underwent apoptosis in response to anti-Fas/CD95, but showed resistance to TRAIL, unless they were co-treated with actinomycin D. Interestingly, CML-PBB and KU-812 cells exhibited the opposite response pattern with resistance to anti-Fas/CD95, but significant susceptibility to TRAIL-induced apoptosis. Our data show that anti-Fas/CD95 and TRAIL differentially regulate apoptosis of normal and neoplastic human basophils, which may direct the development of novel therapeutic strategies.

Gyrate atrophy: clinical and genetic findings in a female without arginine-restricted diet during her first 39 years of life and report of a new OAT gene mutation.

We report the clinical and genetic data obtained at a 17-year follow-up examination of a patient with gyrate atrophy, without an arginine-restricted diet. Patient examinations included visual acuity (VA), perimetry, biomicroscopy, funduscopy, fundus photography, fundus autofluorescence (FAF), spectral-domain optical coherence tomography (OCT), and standard full-field electroretinography (ERG). Blood samples were taken for measurement of serum ornithine level and molecular genetic analysis of the OAT gene. The female was 22 years of age when gyrate atrophy was diagnosed based on peripheral chorioretinal atrophy and an increased ornithine level. Reexamination after 17 years revealed a reduced VA (0.25 OU), dense cataract, extensive peripheral chorioretinal atrophy, a further increased ornithine level, but only slow progression of visual field constriction, and still detectable ERG amplitudes. FAF was absent in the atrophic periphery and almost homogeneous at the posterior pole except parafoveally. OCT showed interruption of the foveal inner/outer segment junction and parafoveal microcystoid spaces. After cataract surgery, VA increased to the same values as those found at the age of 22 years (0.5 OD, 0.6 OS). Molecular analysis revealed a new deletion c.532_536delTGGGG (p.Trp178X) and a known mutation c.897C>G (p.Tyr299X) in the OAT gene. Although the patient had refused to diet during her first 39 years of life, the gyrate atrophy showed a very slow progression. FAF allows evaluating the integrity of the retinal pigment epithelium and may help to delimit gyrate atrophy from choroideremia. Interruption of foveal inner/outer segment junction and cystoid macula edema appears in gyrate atrophy.

A subgroup of age-related macular degeneration is associated with mono-allelic sequence variants in the ABCA4 gene.

Purpose. Age-related macular degeneration (AMD) is a heterogeneous condition of high prevalence and complex etiology involving genetic as well as environmental factors. By fundus autofluorescence (FAF) imaging, AMD can be classified into several distinct phenotypes, with one subgroup characterized by fine granular pattern with peripheral punctate spots (GPS[+]). Some features of GPS[+] overlap with Stargardt disease (STGD1), a recessive macular dystrophy caused by biallelic sequence variants in the ATP-binding cassette transporter 4 (ABCA4) gene. The aim of this study was to investigate the role of ABCA4 in GPS[+]. Methods. The ABCA4 gene was sequenced in 25 patients with the GPS[+] phenotype and 29 with geographic atrophy (GA)-AMD but no signs of GPS (GPS[-]). In addition, frequencies of risk-increasing alleles at three known AMD susceptibility loci, including complement factor H (CFH), age-related maculopathy susceptibility 2 (ARMS2), and complement component 3 (C3), were evaluated. Results. We demonstrate that GPS[+] is associated significantly with monoallelic ABCA4 sequence variants. Moreover, frequencies of AMD risk-increasing alleles at CFH, ARMS2, and C3 are similar in GPS[+] and STGD1 patients, with risk allele frequencies in both subcategories comparable to population-based control individuals estimated from 3,510 individuals from the NHLBI Exome Sequencing Project. Conclusions. Our data suggest that the GPS[+] phenotype is accounted for by monoallelic variants in ABCA4 and unlikely by the well-established AMD risk-increasing alleles at CFH, ARMS2, and C3. These findings provide support for a complex role of ABCA4 in the etiology of a minor proportion of patients with AMD.

Primary failure of eruption (PFE)--clinical and molecular genetics analysis.

BACKGROUND: The term "primary failure of eruption" (PFE) refers to the complete or partial failure of a primary non-ankylosed tooth to erupt due to a disturbance of the eruption mechanism. Up to now, the molecular basis for this failure was unknown. PATIENTS AND METHODS: Four families were studied in whom at least two members were affected by non-syndromic PFE as part of a clinical and molecular genetics study. Radiological diagnostics (OPTs) were carried out in all patients and their unaffected relatives (control group). The genetic analysis included a genomewide linkage analysis followed by direct DNA sequencing of positional candidate genes. RESULTS: Starting from the index patients, we were able to reconstruct pedigrees over two and/or three generations in the families that indicated an autosomal-dominant mode of inheritance of non-syndromic PFE. Fifteen patients were diagnosed with PFE. Gender distribution was nearly equal (7 female, 8 male). Molecular genetic analysis of the PTHR1 gene revealed three distinct heterozygous mutations (c.1050-3C>G; c.543+1G>A; c.463G>T). Unaffected persons exhibited no mutations. CONCLUSIONS: Knowledge of the genetic causes of non-syndromic PFE can now be used for the differential diagnosis of eruption failure. It permits affected family members to be identified early and may lead to new treatment possibilities in the long term. The genetically-verified diagnosis of "primary failure of eruption" can protect patients and orthodontists from years of futile treatment, because orthodontic treatment alone does not lead to success. Moreover, it has a negative influence on unaffected teeth and areas of the jaw.

Progression of retinal pigment epithelial alterations during long-term follow-up in female carriers of choroideremia and report of a novel CHM mutation.

OBJECTIVES: To report clinical and functional findings in 2 female carriers of choroideremia who were followed up for 11 and 17 years and who showed progression of fundus alterations; and to report a novel CHM mutation. METHODS: We performed follow-ups in 2 female carriers of choroideremia, including repeated clinical and electrophysiologic examinations and fundus autofluorescence. Molecular analysis of the CHM gene was done by direct sequencing of the coding exons. RESULTS: Follow-up of female carrier 327 took place during 17 years. A second female carrier (subject 869) with a novel gene mutation in CHM was followed up for 11 years. The 2 carriers showed marked pigmentary alterations in the periphery of the retina. At the initial visit, carrier 869 had multiple small, yellowish flecks in the macula. Both carriers developed subnormal 30-Hz flicker responses on full-field electroretinography during follow-up, whereas electrooculography responses were normal. In both carriers, progression of fundus alterations was noted. Fundus autofluorescence images showed multiple small flecks with reduced autofluorescence. CONCLUSIONS: Over time, fundus alterations in female carriers of choroideremia are visible, and mild cone dysfunction might develop. Multiple yellowish flecks can exist in the macula. The typical mottled irregularity in fundus autofluorescence is a valuable diagnostic criterion that facilitates specific genetic testing. Clinical Relevance Fundus alterations in female carriers of choroideremia can progress over time and a mild generalized cone dysfunction can develop. Characteristic irregularities are seen in fundus autofluorescence imaging, which is helpful in identifying female carriers of choroideremia.

Phenotypic variability and long-term follow-up of patients with known and novel PRPH2/RDS gene mutations.

PURPOSE: To describe the phenotypic variability in 22 patients with PRPH2 gene mutations and to report six novel mutations. DESIGN: Retrospective study. METHODS: Clinical examinations included color vision testing, perimetry, fundus autofluorescence (FAF), fluorescein angiography, optical coherence tomography (OCT), and full-field and multifocal electroretinography (International Society for Clinical Electrophysiology of Vision standards). Blood samples were taken for deoxyribonucleic acid (DNA) extraction and mutation screening was performed by direct sequencing of polymerase chain reaction amplicons. RESULTS: Eleven unrelated patients and four unrelated families each with two affected members as well as one family with three affected members were examined. Diagnoses included central areolar choroidal dystrophy (CACD; n = 9), autosomal dominant retinitis pigmentosa (adRP; n = 7), adult vitelliform macular dystrophy (n = 3), and cone-rod dystrophy (CRD; n = 3). FAF was abnormal in all patients and showed various retinal pigment epithelial alterations, in CACD with a speckled FAF pattern. OCT revealed reduced retinal thickness, mostly in CACD, subretinal lesions, macula edema, or was normal. Follow-up (n = 12; range, 1.3 to 26 years) showed a slow progression of the retinal dystrophies. DNA testing revealed previously reported PRPH2 mutations in two families and eight individuals of whom two carried the same mutation but had different phenotypes. Novel PRPH2 mutations were detected in two families with adRP, in identical twins with CACD, and in each of an individual with CACD, CRD, and adRP. CONCLUSIONS: This series describes the broad spectrum of phenotypes associated with PRPH2 mutations. FAF and OCT are helpful tools for diagnosis and evaluation of disease progression. We report novel PRPH2 mutations in patients with CACD, CRD, and adRP.

PTHR1 loss-of-function mutations in familial, nonsyndromic primary failure of tooth eruption.

Tooth eruption is a complex developmental process requiring coordinated navigation through alveolar bone and oral epithelium. Primary failure of tooth eruption (PFE) is associated with several syndromes primarily affecting skeletal development, but it is also known as a nonsyndromic autosomal-dominant condition. Teeth in the posterior quadrants of the upper and lower jaw are preferentially affected and usually result in an open bite extending from anterior to posterior. In this study, we show that familial, nonsyndromic PFE is caused by heterozygous mutations in the gene encoding the G protein-coupled receptor for parathyroid hormone and parathyroid hormone-like hormone (PTHR1). Three distinct mutations, namely c.1050-3C > G, c.543+1G > A, and c.463G > T, were identified in 15 affected individuals from four multiplex pedigrees. All mutations truncate the mature protein and therefore should lead to a functionless receptor, strongly suggesting that haplo-insufficiency of PTHR1 is the underlying cause of nonsyndromic PFE. Although complete inactivation of PTHR1 is known to underlie the autosomal-recessive Blomstrand osteochondrodysplasia (BOCD), a lethal form of short-limbed dwarfism, our data now imply that dominantly acting PTHR1 mutations that lead to haplo-insufficiency of the receptor result in a nonsyndromic phenotype affecting tooth development with high penetrance and variable expressivity.