Search Results (313)

Background/Objectives: Autism spectrum disorders (ASDs) are neurodevelopmental conditions with early onset of clinical manifestations. ASD etiology is highly heterogeneous, with genetic factors being strong determinants of the behavioral problems and neurodevelopmental deficits. Fragile X syndrome (FXS) (OMIM #300624), caused by the transcriptional silencing of the FMR1 gene, represents the most common monogenic cause of autism. Our study included 226 boys with a diagnosis of ASD, for a systematic screening of genetic and epigenetic defects in the FMR1 gene promoter in a Romanian pediatric cohort. Methods: The methods, methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and triplet-primed PCR (TP-PCR)/melt curve analysis (MCA), were chosen for their ability to detect the methylation anomalies (the former) as well as repeat expansions in the FMR1 promoter (the latter). Results: Both methods used in our screening generated concordant results, detecting FMR1 full mutation in 4 out of 226 patients (~1.8%). This yield is similar to data obtained in larger studies. Three out of four boys presented the typical clinical features, in correlation with genetic findings. Conclusions: The combined use of MS-MLPA and TP-PCR/MCA-based assay was, in our experience, useful to fully describe the genetic defects responsible for FXS. A significant variability of clinical presentations was observed in our small group of children with FXS, from mild to severe intellectual disability and from atypical to characteristic dysmorphic features, as well as various behavioral problems. Full article

Phenylketonuria (PKU) is a monogenic disorder caused by pathogenic variants in the gene encoding phenylalanine hydroxylase (PAH), an enzyme essential for phenylalanine (Phe) metabolism. It is characterized by elevated Phe levels, leading to a wide spectrum of clinical phenotypes. These phenotypes are characterized by varying Phe accumulation, dietary tolerance, and heterogeneous cognitive and neurological outcomes, but current monitoring methods, focused primarily on blood Phe levels, are limited in capturing this variability. In this study, we applied mass spectrometry-based advanced quantitative amino acid analyses, untargeted metabolomics, and lipidomics analyses. We examined the plasma metabolite and lipid profiles in a total of 73 individuals with various PKU phenotypes against healthy controls to see how the metabolome and lipidome of the patients change in different phenotypes. We investigated whether novel markers could be associated with metabolic control status. By elucidating the metabolic and lipid fingerprints of PKU’s phenotypic variability, our findings may provide novel insights that could inform the refinement of dietary and pharmacological interventions, thereby supporting the development of more personalized treatment strategies. Full article

Mitochondrial Membrane Protein-Associated Neurodegeneration is a rare monogenic form of neurodegeneration characterized by iron accumulation in the brain. It is due to variants in the orphan gene C19orf12. Since its definition in 2011, many scientific groups have investigated the clinical features and molecular underpinnings of the disorder. In this review, we summarize the main points of progress in this field, trying to highlight the issues that need further attention and efforts to speed up the diagnostic path, improve the existing treatment options, and define targeted therapies. Full article

Cardiomyopathies represent a heterogeneous group of myocardial disorders, traditionally classified by phenotype into hypertrophic, dilated, and arrhythmogenic. Historically, these conditions have been attributed to high-penetrance rare variants in key structural genes, consistent with a classical Mendelian pattern of inheritance. However, emerging evidence suggests that this model does not fully capture the full spectrum and complexity of disease expression. Many patients do not harbor identifiable pathogenic variants, while others carrying well-known disease-causing variants remain unaffected. This highlights the role of incomplete penetrance, likely modulated by additional genetic modifiers. Recent advances in genomics have revealed a broader view of the genetic basis of cardiomyopathies, introducing new players such as common genetic variants identified as risk alleles, as well as intermediate-effect variants. This continuum of genetic risk, reflecting an overall genetic influence, interacts further with environmental and lifestyle factors, likely contributing together to the observed variability in clinical presentation. This model offers a more realistic framework for understanding genetic inheritance and helps provide a clearer picture of disease expression and penetrance. This review explores the evolving genetic architecture of cardiomyopathies, spanning from a monogenic foundation to intermediate-risk variants and complex polygenic contribution. Recognizing this continuum is essential for enhancing diagnostic accuracy, guiding family screening strategies, and enabling personalized patient management. Full article

Lysosomal storage disorders (LSDs) constitute a group of monogenic systemic diseases resulting from deficiencies in specific lysosomal enzymes that cause the intralysosomal accumulation of non- or partially degraded substrates, leading to lysosomal dysfunction. In some cases of LSDs, the bone is more severely affected, thus producing skeletal manifestations in patients. Current therapies, such as enzyme replacement therapy (ERT) and gene therapy (GT), show limited efficacy in correcting skeletal abnormalities. Increasing evidence suggests that microenvironmental disturbances also contribute significantly to disease pathogenesis. Therefore, therapeutic strategies targeting lysosomal dysfunction and microenvironmental dysregulation are needed. Mesenchymal stem-cell-derived extracellular vesicles (MSC-EVs) are emerging as promising candidates in regenerative medicine due to their immunomodulatory, pro-regenerative, and paracrine properties. MSC-EVs have shown potential to modulate the microenvironment and favor tissue repair in bone-related disorders such as osteoarthritis and osteoporosis. Interestingly, MSC-EVs can be engineered to reach the bone and carry therapeutics, including ERT- and GT-related molecules, enabling targeted delivery to hard-to-reach bone regions. This review describes the main features of MSC-EVs and discusses the therapeutic potential of MSC-EVs as a potential cell-free strategy for bone-affected LSDs. Full article

Background: Developmental delay and intellectual disability (DD/ID) are frequently accompanied by epilepsy, and growing evidence implicates variants in voltage-gated calcium channel genes in their pathogenesis. This study aimed to investigate the association of polymorphisms in CACNA1A, CACNA1C, and CACNA1H with DD/ID and epilepsy comorbidity in Korean children. Methods: We retrospectively analyzed 141 pediatric patients diagnosed with DD/ID who underwent whole-exome sequencing (WES) and were not found to have pathogenic monogenic variants. Nine single-nucleotide polymorphisms (SNPs) across CACNA1A, CACNA1C, and CACNA1H were selected based on functional annotation scores and prior literature. Genotype data were extracted from WES variant files, and allele and genotype frequencies were compared with control data from the gnomAD East Asian population and the Korean Reference Genome Database (KRGDB). Subgroup analyses were performed according to epilepsy comorbidity. Results: The CACNA1A rs16023 variant showed a significantly higher B allele frequency in DD/ID patients than in both control datasets and was also associated with epilepsy comorbidity. Genotype distribution analysis revealed that the BB genotype of rs16023 was more frequent in patients with epilepsy. Conclusions: The CACNA1A rs16023 variant may contribute to genetic susceptibility to DD/ID and epilepsy in Korean children, potentially through regulatory mechanisms. These findings support the relevance of calcium channel genes in neurodevelopmental disorders and highlight the importance of integrating functional annotation in variant prioritization. Full article

Cutaneous manifestations can serve as early and sometimes the first clinical indicators in various hereditary cancer predisposition syndromes. This review provides a comprehensive overview of the dermatological signs associated with these syndromes, aiming to facilitate their recognition in clinical practice. Hereditary Breast and Ovarian Cancer syndrome is notably linked to an increased risk of melanoma. BAP1 tumor predisposition syndrome is characterized by BAP1-inactivated melanocytic tumors. Muir–Torre syndrome, a variant of Lynch syndrome, presents with distinctive cutaneous neoplasms such as sebaceous carcinomas, sebaceous adenomas, and keratoacanthomas. PTEN hamartoma tumor syndrome commonly features hamartomatous growths, trichilemmomas, acral keratoses, oral papillomas, and genital lentiginosis. Gorlin syndrome is marked by basal cell carcinomas and palmoplantar pits, while Peutz–Jeghers syndrome is identified by mucocutaneous pigmentation. In familial adenomatous polyposis, the cutaneous findings include epidermoid cysts, fibromas, desmoid tumors, and lipomas. Additionally, we examined monogenic disorders associated with cancer risk and skin involvement, such as xeroderma pigmentosum, neurofibromatosis type 1, familial atypical multiple-mole melanoma syndrome, and Fanconi anemia. The early recognition of these dermatologic features is essential for a timely diagnosis and the implementation of appropriate surveillance strategies in individuals with hereditary cancer syndromes. Full article

Inflammatory bowel diseases (IBDs) are chronic inflammatory conditions of the gastrointestinal tract that are multifactorial in nature. The pathophysiology involves interactions between the host immune system and environmental factors, including the gut microbiota, in genetically predisposed individuals. Advances in understanding these interactions have led to the development of novel therapeutic targets, ranging from anti-TNFα to more recent anti-interleukin 23 treatments. However, some patients still experience resistance to these therapies. Monogenic intestinal diseases (MIDs), which present with more severe symptoms than IBD and typically begin early in life, result from significant disruptions of intestinal homeostasis. MIDs are driven by mutations in a single gene, offering a unique opportunity to explore the mechanisms underlying intestinal homeostasis in health. In this review, we provide a comprehensive overview of the mechanisms of intestinal homeostasis by examining the cellular and molecular features of IBD and MID pathophysiologies. Full article

Background/Objectives: Karyomapping, a genome-wide SNP analysis, has drastically changed the approach to preimplantation genetic testing for monogenic disorders (PGT-M). However, there are cases in which karyomapping cannot be applied due to an insufficient number of informative SNPs. In this study, we aimed to analyze for the first time whether an insufficient number of informative SNPs is related to the family member used as a reference. Methods: For the karyomapping pre-clinical test, in addition to the couple, one of the DNA samples from an additional family member (children, parent, sibling) is used as a reference for phasing the SNP allele. We analyzed 263 couples who underwent karyomapping for PGT-M at the CHA Fertility Center from May 2020 to December 2022. karyomapping data was scanned on an Illumina NextSeq and analyzed through the BlueFuse Multi software version 4.5. Results: Preclinical karyomapping tests were performed in 263 couples with 58 monogenic diseases. Karyomapping was applicable to PGT-M for 241 (91.6%) couples and not applicable for 22 (8.4%) couples. The percentages of “not applicable” cases according to the reference family member were 1.3% (1/80) in the children group, 5.4% (8/148) in the parent group, and 37.1% (13/35) in the sibling group. Among the genetic diseases studied, couples with neurofibromatosis type 1 (6/27, 22.2%) and Kennedy disease (5/5, 100%) had the highest rate of non-applicable cases. Conclusions: Our results suggest that a child or parent may be better than the sibling for karyomapping in PGT-M. These data provide useful information for selecting a reference among the family members for preclinical karyomapping tests. Full article

Background: Wolfram syndrome (WFS), also known as DIDMOAD, is a rare monogenic neurodegenerative disorder characterized by four key components: non-autoimmune insulin-dependent diabetes mellitus (DM), optic atrophy, sensorineural hearing loss, and diabetes insipidus. Although it significantly affects quality of life, gonadal dysfunction, particularly hypogonadism, remains underrecognized. Methods: In total, 45 patients (25 men, 20 women) with genetically confirmed WFS from a single tertiary-care center were prospectively followed to assess gonadal function. Men underwent hormonal evaluations, semen analysis, imaging tests, and testicular biopsies. In women, data on age at menarche, menstrual irregularities, and age at menopause were recorded. Hormonal analyses, including anti-Müllerian hormone (AMH) levels, and imaging tests were also conducted. Results: Hypogonadism was identified in 19 men (76.0%), of whom 17 (68.0%) had hypergonadotropic hypogonadism and 2 (8.0%) had hypogonadotropic hypogonadism. Testicular biopsies showed seminiferous tubule damage, Sertoli cell predominance, and reduced Leydig cells. Azoospermia was observed in 12 patients, whereas others presented with oligozoospermia, teratozoospermia, or asthenozoospermia. Most patients exhibited low testosterone levels along with elevated LH and FSH, suggesting primary testicular failure, except for two cases of hypogonadotropic hypogonadism. Correlations between biomarkers, onset age and severity have been analyzed and provide important insights regarding medical treatment. In women, menstrual irregularities were universal, with 20% experiencing premature menopause. Four patients had low AMH levels, with ovarian atrophy in three and a postmenopausal uterus in two, indicating early hypogonadism risk. Conclusions: Gonadal dysfunction is a significant yet overlooked feature of WFS, requiring systematic evaluation during puberty and beyond. Proper management is essential to mitigate metabolic disturbances and psychological impacts, including infertility distress, relationship challenges, and quality of life concerns. Addressing sexual health is crucial as WFS patients live longer and aspire to establish relationships or start families. Full article

Background: Charcot–Marie–Tooth disease (CMT) is a genetically and clinically heterogeneous group of progressive peripheral neuropathies. Preimplantation genetic testing for monogenic disorders (PGT-M), a well-established assisted reproductive technology used to detect specific genetic mutations in embryos before implantation, has been used in common CMT subtypes (e.g., CMT1A); however, data on its application across rarer subtypes and in de novo cases remain limited. In this study, we aimed to evaluate the effectiveness of PGT-M using karyomapping in achieving clinical pregnancies and healthy births in families affected by various CMT types, including the previously unreported subtypes CMT1B and CMT2. Methods: We analyzed 31 PGT-M cycles from 13 families with genetically confirmed CMT, including cases of previously unreported subtypes CMT1B and CMT2. A total of 150 embryos were biopsied. Through 19 embryo transfer cycles, 21 embryos were transferred. In one de novo case, karyomapping was performed using amniotic fluid from an affected fetus as a reference. Results: Of the 19 embryo transfers, 15 resulted in clinical pregnancies. Prenatal diagnosis confirmed that all fetuses were unaffected, and all pregnancies resulted in healthy live births. Successful phasing using amniotic fluid from an affected fetus enabled accurate embryo selection and led to the birth of healthy twins. Conclusions: PGT-M using karyomapping is a rapid and reliable method for achieving successful pregnancies in families affected by diverse CMT subtypes, including de novo cases, and supports broader applicability to other monogenic disorders. Full article

Neurocutaneous syndromes represent a clinically and genetically heterogeneous group of disorders, with tuberous sclerosis complex (TSC), von Hippel–Lindau syndrome (VHL), and ataxia–telangiectasia (A-T) exemplifying some of the most complex entities within this category. These syndromes have traditionally been considered monogenic disorders, caused by germline mutations in tumor suppressor or regulatory genes. However, they exhibit a striking degree of phenotypic variability and divergent clinical trajectories that cannot be fully explained by their underlying genetic alterations alone. Increasingly, epigenetic regulatory mechanisms, such as DNA methylation, histone modifications, chromatin remodeling, and non-coding RNA (ncRNA) activity, are recognized as key modulators of gene expression, cellular differentiation, and tissue-specific function. Disruption of these mechanisms has been implicated in disease pathogenesis, tumorigenesis, and neurodegeneration associated with TSC, VHL, and A-T. Aberrant epigenetic profiles may underlie the observed variability in clinical outcomes, even among individuals with identical mutations. This review consolidates current evidence on the epigenetic landscape of these syndromes, elucidating how these modifications may influence disease behavior and contribute to incomplete genotype–phenotype correlations. By integrating epigenetic insights with known molecular pathways, a more nuanced understanding of disease biology emerges, with potential implications for diagnostic stratification, prognostic assessment, and therapeutic innovation. Full article

Hyperechogenicity of the substantia nigra (SN) is observed using transcranial ultrasonography in patients with Parkinson’s Disease. In this study, we investigated whether monogenic forms of PD are more prevalent in these patients and clinically defined their characteristics. Eighty-eight PD patients were part of the analysis. All patients received clinical diagnoses from experienced movement disorder specialists. Each patient underwent transcranial ultrasonography and genetic testing for mutations in the SNCA, PRKN, LRRK2, DJ1, and PINK1 genes. SN hyperechogenicity was identified in 48 patients. Compared to the non-hyperechogenicity group, these patients did not have monogenic forms of PD more frequently, but they did have REM sleep behavior disorder significantly more often, lived in rural areas, and experienced a later age of disease onset. Our study indicated no association between substantia nigra echogenicity and the presence of mutations in the SNCA, LRRK2, DJ1, PRKN, and PINK1 genes. Hyperechogenicity of the substantia nigra, however, remains a common finding in patients with Parkinson’s Disease, correlating with certain features of the disease. Full article

Preimplantation genetic testing (PGT) has been used in various forms over the last two decades. PGT involves testing early embryos following in vitro fertilization and has now become an accepted part of genetic testing. Nowadays, PGT serves as a resource for couples who have a family history of monogenic disorders, wherein the fetus is at high risk of inheriting the condition. PGT is also used to improve pregnancy outcomes in IVF patients in cases of recurrent IVF implantation failure, recurrent miscarriages, as well as male factor. It is also used in screening for sex-linked disorders and sourcing stem cells for therapy. The latest PGT direction is polygenic embryo screening (PES, PGT-P), which allows the identification of embryos that are at elevated risk for significant diseases in adulthood, such as coronary artery disease (CAD), diabetes, hypertension, and breast cancer. As the prevalence and the potential for the use of PES grow, fundamental ethical issues have been underlined, raising concerns about the broader implications of genetic testing. This narrative review summarizes indications, methods, applications, and limitations for PGT, with a particular focus on PES. Full article

Moyamoya disease (MMD) is a rare yet clinically significant cerebrovascular disorder characterized by progressive stenosis of the distal internal carotid artery and/or its principal branches, accompanied by the development of characteristic collateral vessel networks. This disease demonstrates a complex multifactorial etiology with strong genetic determinants, as evidenced by its distinct geographical distribution patterns and familial clustering. Recent genetic researches have identified multiple pathogenic mutations contributing to MMD development through three principal mechanisms: progressive vascular stenosis, abnormal angiogenesis, and dysregulated inflammatory responses. Furthermore, moyamoya syndrome frequently occurs as a secondary vascular complication in various monogenic disorders. This review provides a comprehensive analysis of recent genetic advances in MMD in view of diverse pathogenic pathways, offering valuable perspectives on the molecular mechanisms underlying disease development and potential therapeutic targets. Full article