Visual Function and Ophthalmological Findings in CHARGE Syndrome: Revision of Literature, Definition of a New Clinical Spectrum and Genotype Phenotype Correlation.
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SUBMITTER: Onesimo R
PROVIDER: S-EPMC8303791 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:PurposeJoubert syndrome (JS) is caused by mutations in >34 genes that encode proteins involved with primary (nonmotile) cilia and the cilium basal body. This study describes the varying ocular phenotypes in JS patients, with correlation to systemic findings and genotype.DesignPatients were systematically and prospectively examined at the National Institutes of Health (NIH) Clinical Center in the setting of a dedicated natural history clinical trial.ParticipantsNinety-nine patients with JS examined at a single center.MethodsAll patients underwent genotyping for JS, followed by complete age-appropriate ophthalmic examinations at the NIH Clinical Center, including visual acuity (VA), fixation behavior, lid position, motility assessment, slit-lamp biomicroscopy, dilated fundus examination with an indirect ophthalmoscope, and retinoscopy. Color and fundus autofluorescence imaging, Optos wide-field photography (Dunfermline, Scotland, UK), and electroretinography (ERG) were performed when possible.Main outcome measuresThe VA (with longitudinal follow-up where possible), ptosis, extraocular muscle function, retinal and optic nerve status, and retinal function as measured by ERG.ResultsAmong patients with JS with quantifiable VA (68/99), values ranged from 0 logarithm of the minimum angle of resolution (logMAR) (Snellen 20/20) to 1.5 logMAR (Snellen 20/632). Strabismus (71/98), nystagmus (66/99), oculomotor apraxia (60/77), ptosis (30/98), coloboma (28/99), retinal degeneration (20/83), and optic nerve atrophy (8/86) were identified.ConclusionsWe recommend regular monitoring for ophthalmological manifestations of JS beginning soon after birth or diagnosis. We demonstrate delayed visual development and note that the amblyogenic time frame may last significantly longer in JS than is typical. In general, patients with coloboma were less likely to display retinal degeneration, and those with retinal degeneration did not have coloboma. Severe retinal degeneration that is early and aggressive is seen in disease caused by specific genes, such as CEP290- and AHI1-associated JS. Retinal degeneration in INPP5E-, MKS1-, and NPHP1-associated JS was generally milder. Finally, ptosis surgery can be helpful in a subset of patients with JS; decisions as to timing and benefit/risk ratio need to be made on an individual basis according to expert consultation.
| S-EPMC8932443 | biostudies-literature
Project description:CHARGE syndrome is a well-established multiple-malformation syndrome with distinctive consensus diagnostic criteria. Characteristic associated anomalies include ocular coloboma, choanal atresia, cranial nerve defects, distinctive external and inner ear abnormalities, hearing loss, cardiovascular malformations, urogenital anomalies, and growth retardation. Recently, mutations of the chromodomain helicase DNA-binding protein gene CHD7 were reported to be a major cause of CHARGE syndrome. We sequenced the CHD7 gene in 110 individuals who had received the clinical diagnosis of CHARGE syndrome, and we detected mutations in 64 (58%). Mutations were distributed throughout the coding exons and conserved splice sites of CHD7. Of the 64 mutations, 47 (73%) predicted premature truncation of the protein. These included nonsense and frameshift mutations, which most likely lead to haploinsufficiency. Phenotypically, the mutation-positive group was more likely to exhibit cardiovascular malformations (54 of 59 in the mutation-positive group vs. 30 of 42 in the mutation-negative group; P=.014), coloboma of the eye (55 of 62 in the mutation-positive group vs. 30 of 43 in the mutation-negative group; P=.022), and facial asymmetry, often caused by seventh cranial nerve abnormalities (36 of 56 in the mutation-positive group vs. 13 of 39 in the mutation-negative group; P=.004). Mouse embryo whole-mount and section in situ hybridization showed the expression of Chd7 in the outflow tract of the heart, optic vesicle, facio-acoustic preganglion complex, brain, olfactory pit, and mandibular component of the first branchial arch. Microarray gene-expression analysis showed a signature pattern of gene-expression differences that distinguished the individuals with CHARGE syndrome with CHD7 mutation from the controls. We conclude that cardiovascular malformations, coloboma, and facial asymmetry are common findings in CHARGE syndrome caused by CHD7 mutation.
| S-EPMC1380237 | biostudies-literature
Project description:PURPOSE: To report a new sporadic case of membrane frizzled-related protein gene (MFRP)-related syndrome with a 30-month follow-up, and to review the literature for genotype-phenotype correlation in MFRP mutations. METHODS: A complete ophthalmological evaluation was performed at presentation and 30 months later, including best-corrected visual acuity test, slit lamp examination, fundoscopy, kinetic perimetry, electroretinography, fundus imaging (color, red-free, and autofluorescence), and morphologic-biometric analysis of the eye structures with an optical biometer, anterior-segment optical coherence tomography, retinal optical coherence tomography, and a confocal scanning laser for optic nerve head study. Polymerase chain reaction amplification of DNA obtained from peripheral blood lymphocytes and nucleotide sequencing of the complete MFRP gene were performed. The literature on cases of posterior microphthalmos and retinitis pigmentosa associated with MFRP mutations was reviewed. RESULTS: A 33-year-old female patient presented with posterior microphthalmos, retinitis pigmentosa with patches of retinal pigmented epithelium atrophy and scarce pigment mobilization, foveoschisis, and optic nerve drusen. After 30 months, progression of rod-cone retinal degeneration was detected. One obligate carrier showed a normal eye phenotype. A homozygote mutation in the MFRP gene (c.492delC), predicting a truncated protein (P166fsX190), was identified with genetic analysis. To our knowledge, 17 cases of MFRP-related syndrome have been reported in the literature, including the patient described herein. The phenotype of the syndrome, expressivity, and age of onset varied among and within the affected families. However, all patients sharing homozygous mutation c.492delC (alternatively named c.498delC) showed a complete phenotype (including foveoschisis and optic nerve head drusen), and similar fundus characteristics. CONCLUSIONS: A new sporadic case of MFRP-related syndrome is reported. Review of the literature showed variability in the phenotype, but initial elements of genotype-phenotype correlation have been identified in patients sharing the mutation of the present case.
| S-EPMC3482175 | biostudies-literature
Project description:Blepharophimosis syndrome (BPES), an autosomal dominant syndrome in which an eyelid malformation is associated (type I) or not (type II) with premature ovarian failure (POF), has recently been ascribed to mutations in FOXL2, a putative forkhead transcription factor gene. We previously reported 22 FOXL2 mutations and suggested a preliminary genotype-phenotype correlation. Here, we describe 21 new FOXL2 mutations (16 novel ones) through sequencing of open reading frame, 5' untranslated region, putative core promoter, and fluorescence in situ hybridization analysis. Our study shows the existence of two mutational hotspots: 30% of FOXL2 mutations lead to polyalanine (poly-Ala) expansions, and 13% are a novel out-of-frame duplication. In addition, this is the first study to demonstrate intra- and interfamilial phenotypic variability (both BPES types caused by the same mutation). Furthermore, the present study allows a revision of the current genotype-phenotype correlation, since we found exceptions to it. We assume that for predicted proteins with a truncation before the poly-Ala tract, the risk for development of POF is high. For mutations leading to a truncated or extended protein containing an intact forkhead and poly-Ala tract, no predictions are possible, since some of these mutations lead to both types of BPES, even within the same family. Poly-Ala expansions may lead to BPES type II. For missense mutations, no correlations can be made yet. Microdeletions are associated with mental retardation. We conclude that molecular testing may be carefully used as a predictor for POF risk in a limited number of mutations.
| S-EPMC379240 | biostudies-literature
Project description:Cornelia de Lange syndrome (CdLS) is a clinically and genetically heterogeneous developmental disorder. Clinical features include growth retardation, intellectual disability, limb defects, typical facial dysmorphism, and other systemic involvement. The increased understanding of the genetic basis of CdLS has led to diagnostic improvement and expansion of the phenotype. Mutations in five genes (NIPBL, SMC1A, SMC3, RAD21, and HDAC8), all regulators or structural components of cohesin, have been identified. Approximately 60% of CdLS cases are due to NIPBL mutations, 5% caused by mutations in SMC1A, RAD21, and HDAC8 and one proband was found to carry a mutation in SMC3. To date, 311 CdLS-causing mutations are known including missense, nonsense, small deletions and insertions, splice site mutations, and genomic rearrangements. Phenotypic variability is seen both intra- and intergenically. This article reviews the spectrum of CdLS mutations with a particular emphasis on their correlation to the clinical phenotype.
| S-EPMC3880228 | biostudies-literature
Project description:Heterozygous, de novo mutations in the glial fibrillary acidic protein (GFAP) gene have recently been reported in 12 patients affected by neuropathologically proved Alexander disease. We searched for GFAP mutations in a series of patients who had heterogeneous clinical symptoms but were candidates for Alexander disease on the basis of suggestive neuroimaging abnormalities. Missense, heterozygous, de novo GFAP mutations were found in exons 1 or 4 for 14 of the 15 patients analyzed, including patients without macrocephaly. Nine patients carried arginine mutations (four had R79H; four had R239C; and one had R239H) that have been described elsewhere, whereas the other five had one of four novel mutations, of which two affect arginine (2R88C and 1R88S) and two affect nonarginine residues (1L76F and 1N77Y). All mutations were located in the rod domain of GFAP, and there is a correlation between clinical severity and the affected amino acid. These results confirm that GFAP mutations are a reliable molecular marker for the diagnosis of infantile Alexander disease, and they also form a basis for the recommendation of GFAP analysis for prenatal diagnosis to detect potential cases of germinal mosaicism.
| S-EPMC1274357 | biostudies-literature
Project description:GM2-gangliosidosis, AB variant is a very rare form of GM2 gangliosidosis due to a deficiency of GM2 activator protein, associated with autosomal recessive mutations in GM2A. Less than ten patients, confirmed by molecular analysis, have been described in the literature.A 12-month-old Hmong girl presented to the neurometabolic clinic for evaluation of global developmental delay, hypotonia, and cherry red spots. The parents were not known to be consanguineous. Her examination was remarkable for hypotonia with hyperreflexia and excessive startling. The head circumference was normal. An extensive neurometabolic evaluation was negative.Developmental regression began at 14 months of age. Retinal examination at 16 months of age disclosed 4+ cherry red/black spots with "heaped up" ring of whitish infiltrate surrounding both foveae but no evidence of optic atrophy or peripheral retinal abnormalities. Repeat magnetic resonance imaging (MRI) scan at 17 months of age revealed delayed but interval myelination associated with abnormal signal intensity of the bilateral thalami presenting as T2 hyperintensity of the posterior thalami in the region of the pulvinar nuclei and T2 hypointensity in the anterior thalami. Sequencing of the GM2A gene revealed a homozygous c.160 G>T mutation, predicted to result in a premature protein termination p. Glu54*.
| S-EPMC5059184 | biostudies-literature
Project description:Mutations in the receptor expression enhancing protein 1 (REEP1) have recently been reported to cause autosomal dominant hereditary spastic paraplegia (HSP) type SPG31. In a large collaborative effort, we screened a sample of 535 unrelated HSP patients for REEP1 mutations and copy number variations. We identified 13 novel and 2 known REEP1 mutations in 16 familial and sporadic patients by direct sequencing analysis. Twelve out of 16 mutations were small insertions, deletions or splice site mutations. These changes would result in shifts of the open-reading-frame followed by premature termination of translation and haploinsufficiency. Interestingly, we identified two disease associated variations in the 3'-UTR of REEP1 that fell into highly conserved micro RNA binding sites. Copy number variation analysis in a subset of 133 HSP index patients revealed a large duplication of REEP1 that involved exons 2-7 in an Irish family. Clinically most SPG31 patients present with a pure spastic paraplegia; rare complicating features were restricted to symptoms or signs of peripheral nerve involvement. Interestingly, the distribution of age at onset suggested a bimodal pattern with the appearance of initial symptoms of disease either before the age of 20 years or after the age of 30 years. The overall mutation rate in our clinically heterogeneous sample was 3.0%; however, in the sub-sample of pure HSP REEP1 mutations accounted for 8.2% of all patients. These results firmly establish REEP1 as a relatively frequent autosomal dominant HSP gene for which genetic testing is warranted. We also establish haploinsufficiency as the main molecular genetic mechanism in SPG31, which should initiate and guide functional studies on REEP1 with a focus on loss-of-function mechanisms. Our results should be valid as a reference for mutation frequency, spectrum of REEP1 mutations, and clinical phenotypes associated with SPG31.
| S-EPMC2841798 | biostudies-literature
Project description:BackgroundA comprehensive understanding of the genetic basis of rare diseases and their regulatory mechanisms is essential for human molecular genetics. However, the genetic mutant spectrum of pathogenic genes within the Chinese population remains underrepresented. Here, we reported previously unreported functional ABHD12 variants in two Chinese families and explored the correlation between genetic polymorphisms and phenotypes linked to PHARC syndrome.MethodsParticipants with biallelic pathogenic ABHD12 variants were recruited from the Chinese Deafness Genetics Cohort. These participants underwent whole-genome sequencing. Subsequently, a comprehensive literature review was conducted.ResultsTwo Han Chinese families were identified, one with a compound heterozygous variant and the other with a novel homozygous variant in ABHD12. Among 65 PHARC patients, including 62 from the literature and 3 from this study, approximately 90% (57 out of 63) exhibited hearing loss, 82% (50 out of 61) had cataracts, 82% (46 out of 56) presented with retinitis pigmentosa, 79% (42 out of 53) experienced polyneuropathy, and 63% (36 out of 57) displayed ataxia. Seventeen different patterns were observed in the five main phenotypes of PHARC syndrome. A total of 33 pathogenic variants were identified in the ABHD12. Compared with other genotypes, individuals with biallelic truncating variants showed a higher incidence of polyneuropathy (p = 0.006), but no statistically significant differences were observed in the incidence of hearing loss, ataxia, retinitis pigmentosa and cataracts.ConclusionsThe diagnosis of PHARC syndrome is challenging because of its genetic heterogeneity. Therefore, exploring novel variants and establishing genotype-phenotype correlations can significantly enhance gene diagnosis and genetic counseling for this complex disease.
| S-EPMC11312174 | biostudies-literature
Project description:Noonan syndrome (NS) is a developmental disorder characterized by facial dysmorphia, short stature, cardiac defects, and skeletal malformations. We recently demonstrated that mutations in PTPN11, the gene encoding the non-receptor-type protein tyrosine phosphatase SHP-2 (src homology region 2-domain phosphatase-2), cause NS, accounting for approximately 50% of cases of this genetically heterogeneous disorder in a small cohort. All mutations were missense changes and clustered at the interacting portions of the amino-terminal src-homology 2 (N-SH2) and protein tyrosine phosphatase (PTP) domains. A gain of function was postulated as a mechanism for the disease. Here, we report the spectrum and distribution of PTPN11 mutations in a large, well-characterized cohort with NS. Mutations were found in 54 of 119 (45%) unrelated individuals with sporadic or familial NS. There was a significantly higher prevalence of mutations among familial cases than among sporadic ones. All defects were missense, and several were recurrent. The vast majority of mutations altered amino acid residues located in or around the interacting surfaces of the N-SH2 and PTP domains, but defects also affected residues in the C-SH2 domain, as well as in the peptide linking the N-SH2 and C-SH2 domains. Genotype-phenotype analysis revealed that pulmonic stenosis was more prevalent among the group of subjects with NS who had PTPN11 mutations than it was in the group without them (70.6% vs. 46.2%; P<.01), whereas hypertrophic cardiomyopathy was less prevalent among those with PTPN11 mutations (5.9% vs. 26.2%; P<.005). The prevalence of other congenital heart malformations, short stature, pectus deformity, cryptorchidism, and developmental delay did not differ between the two groups. A PTPN11 mutation was identified in a family inheriting Noonan-like/multiple giant-cell lesion syndrome, extending the phenotypic range of disease associated with this gene.
| S-EPMC379142 | biostudies-literature