Search Results (194)

Background/Objectives: Cystic fibrosis (CF) is a rare autosomal recessive genetic disease that has a progressive and multisystemic course. The spectrum and frequency of mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) vary both in European countries and in other geographical regions. The aim of our retrospective study was to present the genetic variants identified in a group of 48 CF patients from the Moldova region (Romania), as well as to establish genotype–phenotype correlations. Methods: Genetic testing was initially performed for 38 CFTR mutations, and in heterozygous patients or those in whom no mutation was detected, CFTR gene sequencing (NGS) was performed. Results: The compound heterozygous genotype was identified in 26 (54.16%) of the patients (with one of the alleles being F508del), while 22 (45.83%) patients had the homozygous F508del genotype. The F508del variant was the most frequent (69.79%), followed by G542X (6.25%, 6/96). Several new variants were also identified that had not been reported in other studies from Romania (R1158X, K598*, R347H, c.2589_2599del, R496H, and CFTRdele2). Phenotypic manifestations in patients with CFTR class I, II, III and VII variants (homozygous and compound heterozygous) were more severe compared to those in patients with CFTR class IV, V and VI mutations, with the data obtained being consistent with those in the literature. Respiratory tract involvement was present in 77.08% of the patients, being more frequent in patients with the compound heterozygous genotype compared to the homozygous F508del genotype. Most patients had exocrine pancreatic insufficiency (EPI) (85.41%). Gastrointestinal manifestations included hepatocytolysis (66.66%) and biliary cirrhosis (0.41%). Meconium ileus was detected in 18.75% of patients, all with a compound heterozygous genotype. Conclusions: We compared the results obtained with data from the literature and correlated the detected CFTR variant (genotype) with the phenotypic manifestations, highlighting certain particularities present in some patients. Genetic testing allows for early diagnosis and adapted management, including personalized treatment for each patient. Identification of novel unclassified CFTR variants still remains a challenge for clinicians. NGS-based screening of heterozygous healthy carriers is important for both genetic counseling and prenatal diagnosis. Full article

Sensenbrenner syndrome, or cranioectodermal dysplasia (CED), is a rare autosomal recessive ciliopathy characterized by craniofacial, skeletal, ectodermal, and renal abnormalities. Ocular involvement, though infrequent, can include retinal dystrophy with early-onset visual impairment. We report a case of a 2-year-old boy with classic clinical features of CED and significant ocular findings. Genetic testing revealed two novel compound heterozygous variants in the WDR19 gene—c.1778G>T and c.3536T>G—expanding the known mutational spectrum associated with this condition. Ophthalmologic evaluation demonstrated bilateral optic nerve hypoplasia, high hyperopia, and severely reduced ERG responses, consistent with global retinal dysfunction. Fundoscopy revealed optic disk pallor, vessel attenuation, and peripheral pigment changes. Multisystem findings included postaxial polydactyly, brachydactyly, short stature, hypotonia, and stage 2 chronic kidney disease. This case highlights the importance of early ophthalmologic screening in suspected CED and underscores the utility of ERG in detecting early retinal involvement. The identification of two previously undescribed WDR19 variants contributes to genotype–phenotype correlation in CED and emphasizes the need for ongoing documentation to guide diagnosis, management, and genetic counseling. Full article

Objectives: This study aims to describe the clinical features and genetic findings of nine Vietnamese patients with autosomal recessive bestrophinopathy. Methods: This retrospective and cross-sectional study included individuals diagnosed with autosomal recessive bestrophinopathy at the Eye Clinic, Vietnam National Geriatric Hospital between May 2024 and April 2025. The patients underwent a visual acuity assessment, retinal multimodal imaging, and molecular testing through BEST1 gene sequencing. Results: Nine patients from seven unrelated families were included. The mean age was 38.6 years (range: 14.1–79.6). Visual acuity ranged from 20/20 to 20/125. All patients showed vitelliform lesions, subretinal deposits, and both intraretinal and subretinal fluid. Other main features included diffuse macular hyperfluorescence and hyperopia. Less common clinical features encompassed glaucoma, retinoschisis, outer retinal thinning, serous retinal detachment, retinal thickening, and thinning of the retinal pigment epithelium. Compound heterozygous or homozygous variants were detected in all patients. Among the five identified BEST1 variants, the most frequent were p.(A195V) and p.(R200*). One novel variant, p.(K289*), was detected. Conclusions: The main clinical retinal features of nine Vietnamese patients with autosomal recessive bestrophinopathy included vitelliform lesions, subretinal deposits, retinal fluid, and diffuse macular hyperfluorescence. The most common variants were p.(A195V) and p.(R200*). Additionally, the identification of various compound heterozygotes and a novel BEST1 variant expands the mutation spectrum of the disease. Full article

Osteogenesis imperfecta type VI is a rare autosomal recessive disorder characterized by bone fragility and defective mineralization, caused by pathogenic variants in the SERPINF1 gene. This study aimed to expand the understanding of OI type VI by analyzing clinical, radiological, and molecular findings in four patients from three unrelated families. Genotyping revealed two novel SERPINF1 variants, c.185G>T (p.Gly62Val) and c.992_993insCA (p.Glu331Asnfs), in a compound heterozygous state in one patient, and a known pathogenic variant, c.261_265dup (p.Leu89Argfs26), in a homozygous form in three patients. Clinical manifestations included early-onset fractures, severe skeletal deformities, impaired mobility, and growth failure. Radiological assessments revealed multilevel and multiplanar bone deformities and metaphyseal widening. RNA analysis demonstrated that the c.992_993insCA variant results in a truncated PEDF protein without triggering nonsense-mediated decay. Population screening identified a carrier frequency of 0.0044 for the c.261_265dup variant, suggesting a founder effect in the Tuvinian population. These findings expand the mutational spectrum of the SERPINF1 gene and provide new insights into the phenotypic variability of OI type VI. Our results highlight the importance of genetic screening in isolated populations and emphasize the need for further research to develop more effective therapeutic approaches for patients with limited response to bisphosphonate therapy. Full article

Background: Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder due to mutations in the ATM gene. Given the residual kinase activity and the type of ATM mutation, its clinical spectrum varies from a severe classic phenotype to a variant atypical form. Material and methods: This study included 28 patients belonging to four big Bulgarian Muslim pedigrees with tremor and dystonia. Whole-exome sequencing was performed in seven affected individuals from two unrelated pedigrees, followed by Sanger sequencing of the coding sequences and exon–intron borders of the ATM gene. Results: Twenty-four of the affected individuals were homozygous for c.8147T>C (p.Val2716Ala) in ATM, while four of the affected individuals were compound heterozygous. The targeted Sanger sequencing along the ATM gene revealed as a second mutation in three of the patients the splice-site variant c.4909+1G>A and in one patient a synonymous pathogenic variant with a splicing effect, c.3576G>A, p.Lys1192. The age at onset in our group varied between 14 days and 40 years. The main symptoms were dystonia and tremor, more prominent in the upper limbs and the neck, and dystonic dysarthria and dysphagia. The clinical course was very slowly progressive. Brain imaging was normal in the majority of the patients. Conclusion: Clinical features due to mutations in the ATM gene can be very broad. The disease may appear as dystonia, especially of early onset, without frank cerebellar involvement and also normal cerebral imaging. A-T should be considered in all patients with unexplained, even mild movement disorders and elevated α fetoprotein. Full article

Background: Children’s interstitial and diffuse lung diseases, commonly referred to as “chILDs”, include around 200 rare conditions that disrupt normal lung function. They are classified, based on etiopathogenesis, into several subgroups, having a varied and multifaceted clinical presentation depending on the type of genetic mutation present. Methods and Results: We describe the case of a late preterm newborn presenting soon after birth with respiratory distress syndrome poorly responsive to surfactant administration, in whom a targeted gene panel analysis for pulmonary congenital diseases, performed using next-generation sequencing (NGS), revealed a novel compound heterozygous variant of the ATP-Binding-Cassette-Subfamily-A-Member-3 (ABCA3) gene. A review of the literature on the subject completes our work. Conclusions: Molecular genetic analysis has become crucial for a more targeted therapeutic treatment, along with the only current curative treatment option that is lung transplantation. Full article

CLN2 disease (neuronal ceroid lipofuscinosis type 2) is an ultra-rare lysosomal storage disorder caused by mutations in the TPP1/CLN2 gene, resulting in impaired tripeptidyl peptidase 1 (TPP1) activity. The timely initiation of enzyme replacement therapy is pivotal for attenuating progressive and irreversible neurodegeneration. This study aimed to benchmark the performance of Oxford Nanopore long-read sequencing (ONT-LRS) for targeted TPP1 mutation detection in a Turkish CLN2 cohort and to assess its concordance with orthogonal validation methods, including Sanger sequencing and enzymatic activity assays. Using a custom-designed primer panel, the entire TPP1 gene (6846 bp) was sequenced on the Oxford Nanopore (ONT) MinIon platform in seven clinically confirmed CLN2 index patients and sixteen unaffected family members. Detected variants were validated via Sanger sequencing and correlated with TPP1 enzyme activity in leucocytes and dried blood spots. Four pathogenic or likely pathogenic TPP1 variants were identified: c.622C>T (p.Arg208*), c.857A>G (p.Asn286Ser), c.1204G>T (p.Glu402*), and c.225A>G (p.Gln75=), along with fourteen additional benign variants. Variant allele frequencies were 50% for c.622C>T, 28.6% for c.1204G>T, 14.3% for c.857A>G, and 7.1% for c.225A>G. Notably, this is the first report to document the homozygous state of the c.857A>G variant and the compound heterozygous configuration of the c225A>G and c.622C>T variants in CLN2 patients, thereby expanding the known mutational landscape. In contrast, the globally common variant c.509-1G>C was not observed, suggesting regional variation in TPP1 mutation patterns. Consistent with the prior Turkish studies, c.622C>T (p.Arg208*) was the most prevalent variant, followed by c.1204G>T (p.Glu402*). TPP1 enzymatic activity was significantly reduced in all affected individuals (p < 0.0001), supporting the functional relevance of the identified variants. ONT-LRS offers a robust, cost-effective platform for high-resolution analysis of the TPP1 gene. Integrating molecular and biochemical data improves diagnostic precision and supports timely, targeted interventions for CLN2 disease, particularly in regions with high consanguinity and limited diagnostic infrastructure. Full article

Background and Objectives: Poretti–Boltshauser syndrome (PBS) is a rare, autosomal recessive disorder caused by pathogenic variants in the LAMA1 gene, resulting in laminin dysfunction. This manifests as a cerebellar malformation with cysts, and patients present with developmental delay and ataxia; however, ocular features are not well-characterised. We aimed to summarise the ocular phenotypes of PBS based on cases reported in the literature. Materials and Methods: A literature search was conducted on Medline, Embase, and PubMed on PBS and its ocular associations. Genetically confirmed PBS cases were reviewed, and genotype–phenotype correlations were investigated. Results: Comprehensive reporting of genotypes and associated systemic and ocular phenotypes was available in 51 patients with PBS, who had 52 distinct variants in LAMA1. Most patients carried homozygous variants. The most common genotype was a c.2935delA homozygous mutation, followed by the c.768+1G>A; c.6701delC compound heterozygous mutation. High myopia was the most common ocular phenotype (n = 39), followed by strabismus (n = 27) and ocular motor apraxia (n = 26). A wide range of other ocular manifestations, including retinal dystrophy, retinal neovascularisation, retinal detachment, strabismus, nystagmus, optic disc and iris hypoplasia, were reported. Patients with the same genotype exhibited variable expressivity. Conclusions: PBS has a broad ocular phenotypic spectrum, and characterisation of this variability is important for making an accurate diagnosis and informing genetic counselling. Full article

Background: Ectodermal dysplasia (ED) encompasses a heterogeneous group of genetic disorders affecting ectoderm-derived structures such as hair, teeth, nails, and sweat glands. Among these, variants in TSPEAR (Thrombospondin-type laminin G domain and epilepsy-associated repeats) have been implicated in autosomal recessive ED type 14 (OMIM 618180), predominantly manifesting with dental anomalies and hair dysplasia. However, the mutational spectrum of TSPEAR remains incompletely characterized. Methods: Two female siblings (ID#1 and ID#4) were clinically evaluated for ED. Genetic analysis, including next-generation sequencing (NGS) and Sanger validation, was conducted to identify TSPEAR variants. A segregation study confirmed inheritance patterns within the family. Results: Both affected siblings exhibited hallmark features of TSPEAR-related ED14, including oligodontia with dysmorphic, pointed maxillary central incisors. Hair thinning and cutaneous angiomas were predominant in ID#4. Genetic analysis identified two compound heterozygous variants in TSPEAR: c.543-1G>A, a splice-site variant likely to disrupt mRNA processing, and NM_144991.2:c.1251G>C(p.Gln417His), a missense variant with predicted deleterious effects. Segregation analysis confirmed maternal and paternal inheritance of the respective variants. A third sibling, ID#5, was identified as a heterozygous carrier without clinical manifestations. Conclusions: This study contributes to the expanding understanding of TSPEAR-related ED14 by providing novel genotype–phenotype correlations. Full article

Patients affected by the rare disease pseudoxanthoma elasticum (PXE) exhibit the calcification of elastic fibers in ocular, dermal, and vascular tissues. These symptoms are triggered by mutations in the ATP-binding cassette transporter subfamily C member 6 (ABCC6), whose substrate remains unknown. Interestingly, ABCC6 is predominantly expressed in the liver tissue, leading to the hypothesis that PXE is a metabolic disorder. We developed a genome-editing system targeting ABCC6 in human immortalized hepatocytes (HepIms) for further investigations. The HepIms were transfected with an ABCC6-specific clustered regulatory interspaced short palindromic repeat (CRISPR-Cas9) genome-editing plasmid, resulting in the identification of a heterozygous (ht^ABCC6HepIm) and a compound heterozygous (cht^ABCC6HepIm) clone. These clones were analyzed for key markers associated with the PXE pathobiochemistry. Hints of impaired lipid trafficking, defects in the extracellular matrix remodeling, the induction of calcification inhibitor expression, and the down regulation of senescence and inflammatory markers in ABCC6-deficienct HepIms were found. Our ABCC6 knock-out model of HepIms provides a valuable tool for studying the metabolic characteristics of PXE in vitro. The initial analysis of the clones mirrors various features of the PXE pathobiochemistry and provides an outlook on future research approaches. Full article

Background: Homocystinuria caused by cystathionine β-synthase (CBS) deficiency is the most common congenital disorder related to sulfur amino acid metabolism, manifested by neurological, vascular, and connective tissue involvement. Methods: This study analyzed the pathogenic gene and molecular mechanism of two classic homocystinuria families through whole exome sequencing and in vitro experiments including minigene assay and expression analysis. Results: Both probands presented with ectopia lentis, high myopia, and abnormally elevated homocysteine level, but one of them had more severe clinical manifestations, including general growth retardation, mild intellectual disability, and severe pectus excavatum. Their family members were phenotypically normal but presented slightly higher levels of homocysteine in plasma. Whole exome sequencing revealed that the two probands carried c.833T>C (p.Ile278Thr) and c.1359-1G>C, and c.919G>A (p.Gly307Ser) and c.131delT (p.Tle44Thrfs*38) compound heterozygous mutations in the CBS gene, respectively. Bioinformatics and in vitro functional analysis showed that the c.1359-1G>C mutation affects the normal splicing of CBS gene, resulting in the production of two abnormal transcripts and the production of two truncated proteins. One of the c.1359-1G>C splicing events (c.1359_1467del) and c.131delT (p.Tle44Thrfs*38) both lead to a significant decrease in CBS mRNA and protein levels. Conclusions: Accurate diagnosis of patients with homocystinuria is of great importance for timely and effective treatment, as well as for the provision of appropriate genetic counseling and prenatal diagnosis guidance to the affected families. Full article

Background/Objective: Ichthyosis vulgaris (IV) is a genodermatosis caused by heterozygous, homozygous, or compound heterozygous variants in the filaggrin (FLG) gene on chromosome 1q21, which also predispose individuals to atopic dermatitis. Its incidence is 1 in 80–250 children. The phenotypic characteristics include palmar hyperlinearity, keratosis pilaris, and a fine scale that is most prominent over the lower abdomen, arms, and legs. Our objective was to study the genetic variants in the FLG gene and their associations in patients with ichthyosis vulgaris. Material and methods: Here, we studied eighteen Mexican sporadic cases and four family members with IV. Steroid sulfatase (STS) enzymatic activity, polymerase chain reaction (PCR), and direct sequencing on the FLG gene were conducted. Results: We found the recurrent heterozygous variant R501* in fifteen sporadic cases, while the other three sporadic cases showed four novel (p.Q2123R, p.H2118R, p.D2120E, p.S3970L) variants and one reported (p.Y2119H) variant; members of family 1 and 2 presented novel homozygous and heterozygous (p.S1482Y, p.P2144S) variants. Conclusions: This study added to the novel pathogenic variants in patients with IV and showed that the stop mutations (p.R501*) in the Mexican population are the most prevalent. Full article

Schimke immuno-osseous dysplasia (SIOD) is a hereditary autosomal-recessive multi-system disorder with early mortality. It has variable clinical presentations, mainly characterised by disproportional short stature, steroid-resistant nephrotic syndrome, spondyloepiphyseal dysplasia, and T-cell immunodeficiency. In the majority of cases, SIOD is caused by pathogenic sequence variants (PSVs) in the SMARCAL1 gene that encodes protein involved in chromatin remodelling. SIOD is an ultra-rare condition, with an incidence of ~1 per 1–3 million live births; data on its genetic and clinical features are scarce. We conducted a retrospective study of 21 paediatric patients with SIOD diagnosed in our centre during the years 2003–2023. The most common extra-renal clinical features were short stature, osseous dysplasia, multiple stigmas, and leukopenia. Proteinuria of varying severity was observed in 16 cases. The five-year overall survival rate (OS) was 89% (95% CI 77–100%), and the ten-year OS was 10%. Next-generation sequencing (NGS) revealed the following PSVs in SMARCAL1 in 19 patients: c.355_500del, c.2542G>T, c.2290C>T, c.2562del, c.2533_2534del, c.1582A>C, c.1933C>T, c.1010T>C, c.1736C>T, c.2070dup, c.2551A>T, c.2149_2150dup, c.939delC, and c.1451T>A; the most common was c.2542G>T, resulting in premature translation termination (p.E848*), and it was found in 14 patients either in a homozygous (four patients) or compound-heterozygous (10 patients) state. According to microsatellite analysis, it is a “founder mutation” in Russia. Full article

Filamin C (FLNC) is a structural protein of muscle fibers. Mutations in the FLNC gene are known to cause myopathies and cardiomyopathies in humans. Here we report the generation by a CRISPR/Cas9 editing system injected into zygote pronuclei of two mouse strains carrying filamin C mutations—one of them (AGA) has a deletion of three nucleotides at position c.7418_7420, causing E>>D substitution and N deletion at positions 2472 and 2473, respectively. The other strain carries a deletion of GA nucleotides at position c.7419_7420, leading to a frameshift and a premature stop codon. Homozygous animals (Flnc^AGA/AGA and Flnc^GA/GA) were embryonically lethal. We determined that Flnc^GA/GA embryos died prior to the E12.5 stage and illustrated delayed development after the E9.5 stage. We performed histological analysis of heart tissue and skeletal muscles of heterozygous strains carrying mutations in different combinations (Flnc^GA/wt, Flnc^AGA/wt, and Flnc^GA/AGA). By performing physiological tests (grip strength and endurance tests), we have shown that heterozygous animals of both strains (Flnc^GA/wt, Flnc^AGA/wt) are functionally indistinguishable from wild-type animals. Interestingly, compound heterozygous mice (Flnc^GA/AGA) are viable, develop normally, reach puberty and it was verified by ECG and Eco-CG that their cardiac muscle is functionally normal. Intriguingly, Flnc^GA/AGA mice demonstrated better results in the grip strength physiological test in comparison to WT animals. We also propose a structural model that explains the complementary interaction of two mutant variants of filamin C. Full article

Background: The nuclear-encoded enzyme polymerase gamma (Pol-γ) is crucial in the replication of the mitochondrial genome (mtDNA), which in turn is vital for mitochondria and hence numerous metabolic processes and energy production in eukaryotic cells. Variants in the POLG gene, which encodes the catalytic subunit of Pol-γ, can significantly impair Pol-γ enzyme function. Pol-γ-associated disorders are referred to as POLG-spectrum disorders (POLG-SDs) and are mainly autosomal-recessively inherited. Clinical manifestations include muscle weakness and fatigue, and severe forms of the disease can lead to premature death in infancy, childhood, and early adulthood, often associated with seizures, liver failure, or intractable epilepsy. Here, we analyzed fibroblasts from a compound heterozygous patient with the established pathogenic variant c.2419C>T; p.(Arg807Cys) and a previously undescribed variant c.678G>C; p.(Gln226His) with a clinical manifestation compatible with POLG-SDs, sensory ataxic neuropathy, and infantile muscular atrophy. We conducted a battery of functional studies for Pol-γ and mitochondrial dysfunction on the patient’s fibroblasts, to test whether the novel variant c.678G>C; p.(Gln226His) may be causative in human disease. Aims/Methods: We analyzed skin-derived fibroblasts in comparison to a first-degree relative (the mother of the patient), an asymptomatic carrier harboring only the established c.2419C>T; p.(Arg807Cys) mutation. Assessments of mitochondrial function included measurements of mtDNA content, mRNA levels of mitochondrial genes, mitochondrial mass, and mitochondrial morphology. Case Presentation and Results: A 13-year-old male presented with symptoms starting at three years of age, including muscle weakness and atrophy in the lower extremities and facial muscles, which later extended to the upper limbs, voice, and back muscles, without further progression. The patient also reported fatigue and muscle pain after physical activity, with no sensory deficits. Extensive diagnostic tests such as electromyography, nerve conduction studies, muscle biopsy, and MRI were unremarkable. Exome sequencing revealed that he carried the compound heterozygous variants in POLG c.678G>C; p.(Gln226His) and c.2419C>T; p.(Arg807Cys), but no other potential genetic pathogenic causes. In comparison to a first-degree relative (his mother) who only carried the c.2419C>T; p.(Arg807Cys) pathogenic mutation, in vitro analyses revealed a significant reduction in mtDNA content (~50%) and mRNA levels of mtDNA-encoded proteins. Mitochondrial mass was reduced by approximately 20%, and mitochondrial interconnectivity within cells was impaired, as determined by fluorescence microscopy and mitochondrial staining. Conclusions: Our findings suggest that the c.678G>C; p.(Gln226His) variant, in conjunction with the c.2419C>T; p.(Arg807Cys) mutation, may compromise mtDNA replication and mitochondrial function and could result in clinically significant mitochondriopathy. As this study is based on one patient compared to a first-degree relative (but with an identical mitochondrial genome), the pathogenicity of c.678G>C; p.(Gln226His) of POLG should be confirmed in future studies, in particular, in conjunction with other POLG-variants. Full article