Enrica Marchionni

De novo KCNA3 variants cause a Developmental and Epileptic Encephalopathy (DEE). We describe a 14-year-old boy presenting with DEE and carrying a heterozygous de novo KCNA3 (NM_002232.4) variant (c.1433T>A, p.Val478Glu) and an inherited KCNQ3 (NM_004519.3) variant (c.1720C>T, p.Pro574Ser). Human dermal fibroblasts (HDFs) were isolated from the patient and an age-matched control. KCNA3 and KCNQ3 transcript levels were quantified by qRT-PCR, showing in patient-HDFs a reduction of 77% and 40%, respectively (p < 0.0001; p = 0.0002). Western blot confirmed decreased KCNA3 and KCNQ3 protein levels by 50% and 35%, respectively (p < 0.05). The contributing role of both variants supports the rationale for a channel-targeted treatment strategy.

Growing evidence suggests that the APOE ε4 allele, a genetic risk factor for Alzheimer disease (AD), influences the clinical-pathologic features of Parkinson disease (PD). APOE ε4 promotes brain amyloid accumulation, indicating a PD subtype more susceptible to late copathology. However, the early correlates of APOE ε4 carriers in PD are not known. In this study, we used a multimodal approach to define the clinical, neurochemical, and neurophysiologic profiles of APOE ε4 carriers in PD at onset. We conducted a single-center, cross-sectional study at Tor Vergata Hospital (Rome, Italy), enrolling newly diagnosed, drug-naïve PD participants and age-matched/sex-matched healthy controls (HCs). Patients with PD were stratified by APOE genotype into ε4 and non-ε4 carriers and evaluated through a comprehensive clinical assessment and the measurement of CSF amyloid peptides and tau protein levels. Group differences in high-density EEG-based functional connectivity (FC) were analyzed using network-based statistics to identify APOE ε4-modulated patterns. Clinical and biomarker associations with network metrics were tested using analysis of covariance and correlation analyses. The study included 66 PD participants (mean age 63.2 [10.1] years, 35% female, 52 ε4 noncarriers, 14 ε4 carriers) and 55 HCs (mean age 62.0 [15.2] years, 42% female). PD ε4, compared with PD non-ε4, demonstrated higher motor impairment, especially in bradykinesia (16.4 [7.6] vs 11.0 [5.6], p = 0.02) and gait disturbances (3.46 [2.23] vs 1.94 [1.46], p = 0.003) Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale part III scores, and reduced CSF amyloid-β42 (Aβ42)/amyloid-β40 (Aβ40) ratio (0.09 [0.03] vs 0.13 [0.03], p < 0.001). Network analyses identified ε4-related FC alterations: decreased α-band connectivity (F = 3.9, p = 0.034) and increased β-band connectivity (F = 9.8, p < 0.001). In ε4 carriers, α-FC correlated inversely with gait disturbances (r = -0.62, p = 0.02) and positively with Montreal Cognitive Assessment (r = 0.57, p = 0.03) and CSF Aβ42/Aβ40 (r = 0.54, p = 0.04). β-FC correlated with bradykinesia in both groups, with stronger associations in ε4 carriers (r = 0.54, p = 0.04) than in non-ε4 (r = 0.28, p = 0.04). APOE ε4 defines a PD subtype characterized by greater motor impairment, reduced CSF Aβ42/Aβ40, and distinct FC abnormalities since the onset. An early amyloid-mediated network disruption thus emerges as the potential biological signature of ε4 carriers. Although limited by single-center and cross-sectional design, this study supports APOE ε4 as a stratification marker for early diagnostic and therapeutic strategies in PD.

The FMR1 gene premutation (55–200 CGG repeats) is usually associated with a wide range of symptoms and phenotypes within the Fragile X‐tremor/ataxia syndrome (FXTAS), but may also manifest as predominant or isolated cognitive decline. We describe three male patients referred for progressive cognitive impairment and behavioral changes. Standard work‐up, including MRI, FDG‐PET, CSF biomarkers, and neuropsychological testing, excluded common dementias. Brain MRI imaging revealed callosal and peduncular white matter changes, while 18FDG‐PET showed consistent anterior cingulate hypometabolism. Genetic analysis confirmed FMR1 premutation in all cases. Clinicians in memory clinics should consider this diagnosis in cases of unexplained cognitive decline.

Background: INPP5E-related retinopathy (INPP5E-RR) is a rare genetic disorder caused by biallelic pathogenic variants in the INPP5E gene, which encodes an enzyme critical for phosphoinositide signaling. While early-onset rod–cone dystrophy is a hallmark feature, detailed longitudinal data on the phenotype are scarce. This study aims to report a 6-year longitudinal assessment of retinal structure and function in a case of non-syndromic INPP5E-RR. Methods: A 42-year-old female proband with compound heterozygous pathogenic missense variants in INPP5E (p.Arg486Cys and p.Arg378Cys) was monitored from 2019 to 2025. She underwent serial comprehensive ophthalmologic evaluations, including optical coherence tomography (OCT), fundus autofluorescence, adaptive optics transscleral flood illumination, full-field 30Hz flicker electroretinography (ERG), and macular frequency-doubling technology perimetry. Results: Over the 6-year follow-up, OCT imaging revealed a progressive decline in the ellipsoid zone (EZ) width, from 1220 µm to 720 µm (~80 µm/year), and in the inner nuclear layer (INL) thickness. The central outer nuclear layer (ONL) thickness was preserved, but intraretinal cysts developed. Functional testing revealed a progressive decline in cone flicker ERG amplitudes, while visual acuity and macular perimetry remained stable. Conclusions: In this genotypically confirmed case, the longitudinal data identify EZ width, INL thickness, and cone flicker ERG as robust biomarkers of disease progression in INPP5E-RR. These parameters are ideal candidates for monitoring therapeutic outcomes in future clinical trials.

Hereditary Angioedema (HAE) due to C1-esterase inhibitor (C1-INH) deficiency or dysfunction (C1-INH-HAE), is an autosomal dominant genetic disease characterized by recurrent cutaneous and submucosal swelling episodes most often caused by heterozygous pathogenic Single Nucleotide Variants (SNVs), small insertions or deletions (indels) or Copy Number Variants (CNVs) in the SERPING1 gene, coding for C1-INH. Rare subtypes of HAE not associated with SERPING1 pathogenic variants (nC1-INH-HAE) have been described. This case report aimed to characterize a 55-year-old proband, without a family history of hereditary diseases, presenting with a clinical diagnosis of C1-INH-HAE, primary Sjögren syndrome, and unexplained neuropathic symptoms. Firstly, targeted Next-Generation Sequencing and Multiple Ligation-dependent Probe Amplification (MLPA) were performed on the proband’s genomic DNA to analyze the SERPING1 gene. Secondly, Chromosomal Microarray Analysis (CMA) and Fluorescence In Situ Hybridization analysis were performed to confirm the cytogenomics results. MLPA detected a heterozygous variant corresponding to the whole SERPING1 gene deletion on chromosome 11, a very rare cause of C1-INH-HAE. CMA defined breakpoints and disclosed an additional pathogenic CNV on chromosome 17, involving PMP22 gene, and causing Neuropathy, Hereditary, With Liability To Pressure Palsies disease. The clinical consequences of SERPING1 and PMP22 haploinsufficiency are associated with the unusual constellation of clinical symptoms, unraveling an unexpected cytogenomics architecture with two co-occurring disease-causing CNVs in a previously genetically undiagnosed patient.

Sudden cardiac death represents an unexpected death for which a strong underlying genetic background has been described. The primary causes are identified in cardiomyopathies and channelopathies, which are heart diseases of the muscle and electrical system, respectively, without coronary artery disease, hypertension, valvular disease, and congenital heart malformations. Genetic variants, especially single nucleotide variants and short insertions/deletions impacting essential myocardial functions, have shown that cardiomyopathies display high heritability. However, genetic heterogeneity, incomplete penetrance, and variable expression may complicate the interpretation of genetic findings, thus delaying the management of seriously at-risk patients. Moreover, recent studies show that the diagnostic yield related to genetic cardiomyopathies ranges from 28 to 40%, raising the need for further research. In this regard, investigating the occurrence of structural variants, especially copy number variants, may be crucial. Based on these considerations, this review aims to provide an overview of copy number variants identified in cardiomyopathies and discuss them, considering diagnostic yield. This review will ultimately address the necessity of incorporating copy number variants into routine genetic testing for cardiomyopathies and channelopathies, a process increasingly enabled by advances in next-generation sequencing technologies.

MYBPC3 pathogenic variants are the most common cause of hypertrophic cardiomyopathy (HCM) and are associated with significant phenotypic heterogeneity. Despite their pathogenic potential, MYBPC3 founder variants persist within specific populations. This study investigates the MYBPC3 c.2309-2 A > G splice variant hypothesizing its founder origin in central Italy. The aim was to confirm the presence of a common haplotype, assess its molecular and clinical impact, and compare the phenotype with that of other MYBPC3 founder variants. Among the 5251 HCM patients recruited at eight Italian referral centers, 1108 probands (21.1%) were identified as carriers of pathogenic or likely pathogenic MYBPC3 variants, and among these, 11.6% carried the c.2309-2 A > G variant. Haplotype reconstruction using short tandem repeats and tag-SNPs revealed a unique 5.2 Mb haplotype segregating with the c.2309-2 A > G variant in all carriers. Age estimation suggested that the variant originated approximately 481 years ago, likely in the Lazio region with clustering in Rome. Clinically, carriers exhibited variable expressivity with age-and sex-dependent penetrance. Males showed earlier onset, higher penetrance and greater disease severity compared to females. RNA analysis showed the retention of both introns 23 and 24, and significantly reduced MYBPC3 expression consistent with haploinsufficiency. Comparative analysis with other MYBPC3 founder variants highlighted differences in phenotypic expression, particularly in left ventricular wall thickness and clinical outcomes. This study establishes c.2309-2 A > G as an Italian MYBPC3 founder mutation, enhancing the understanding of HCM genetics and regional founder effects. These findings emphasize the importance of targeted genetic screening and personalized management for MYBPC3 c.2309-2 A > G carriers.

Background/Objectives: PKP2 (MIM *602861) is the most commonly gene associated with Arrhythmogenic Cardiomyopathy (ACM), an inherited cardiac muscle disorder. The aim of this study was to characterize the phenotypical effect of a heterozygous pathogenic c.2443_2448delAACACCinsGAAA variant in PKP2 gene (NM_004572), detected in two Italian families. Methods: Next Generation Sequencing (NGS) analysis was carried out on two probands, testing a multigenic targeted panel. Segregation analysis through Sanger sequencing detected other three and six positive members, in Family 1 and 2, respectively. Thus, eleven positive patients were identified overall. A deep clinical evaluation was performed according to age groups and clinical parameters (symptoms, electrocardiogram, imaging, and devices). To investigate the molecular effect of the identified variant on PKP2 expression level, total RNA was isolated from peripheral blood mononuclear cells (PBMCs) and quantitative RT-polymerase chain reaction was performed. PKP2 expression at the protein level was analyzed on PBMCs by Western blot analysis. Results: PKP2 transcriptional levels resulted to be reduced by 48% in cells carrying c.2443_2448delAACACCinsGAAA variant compared to WT cells (p = 0.00015). Importantly, Western blot confirmed the reduced level of PKP2 protein in two heterozygous carriers of the variant, confirming the haploinsufficiency effect. Conclusions: The clinical onset of ACM can be Sudden Cardiac Death, and hence, it is recommended to perform a segregation test on first-degree relatives of pathogenic variant carriers, even if they are asymptomatic, with the purpose of promptly detecting those at risk.

Introduction The NOTCH3 gene encodes for an evolutionarily conserved protein, whose functions encompass both embryonic cell proliferation and adult tissue-specific differentiation. Among others, a pivotal role in maintaining functional integrity of neurovascular unit (NVU) is supported by the association of several NOTCH3 gene mutations with neuroimaging markers of cerebral small vessel disease (SVD). Indeed, a pathogenic role of NOTCH3 is recognised in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, an increasing number of NOTCH3 variants with unclear pathogenic role have been identified in patients suspected of having CADASIL. The following case series describes three patients under the age of 65 with clinical diagnosis of nonfluent-variant of primary progressive aphasia (nfvPPA), whose genetic analysis revealed the presence of three distinct novel variants of unknown significance (VUS) in NOTCH3 gene. Results The diagnostic work-up revealed common features among the patients: clinical presentation -nfvPPA at neuropsychological evaluation with consistent extrapyramidal symptoms; neuroimaging -low brain MR burden of SVD and FDG-PET impairment of cortical areas involved in speech production network; and biomarkers –Cerebrospinal fluid (CSF) analysis negative for Alzheimer’s Disease (AD), corroborating suspicion of underlying Frontotemporal Lobe Degeneration (FTLD). Discussion and Conclusion The retrieved VUS in NOTCH3 suggest that the involvement of Notch signalling in pathophysiology of neurodegenerative disease is more complex and needs to be fully explored. Rare variants in SVD-associated genes may influence progression of neurodegeneration via the dysfunction of several vascular pathways.

Prenatal Exome (pES) or Genome (pGS) Sequencing analysis showed a significant incremental diagnostic yield over karyotype and chromosomal microarray analysis (CMA) in fetal structural anomalies. Optimized indications and detection rates in different fetal anomalies are still under investigation. The aim of this study was to assess the incremental diagnostic yield in prenatally diagnosed Central Nervous System (CNS) anomalies. A systematic review on antenatal CNS anomalies was performed according to PRISMA guidelines, including n = 12 paper, accounting for 428 fetuses. Results were pooled in a meta‐analysis fitting a logistic random mixed-effect model. The effect of interest was the incremental diagnostic rate of pES over karyotype/CMA in detecting likely pathogenic/pathogenic Single Nucleotide Variants (SNVs). A further meta-analysis adding the available pGS studies (including diagnostic coding SNVs only) and submeta-analysis on three CNS subcategories were also performed. The pooled incremental diagnostic yield estimate of pES studies was 38% (95% C.I.: [29%;47%]) and 36% (95% C.I.: [28%;45%]) when including diagnostic SNVs of pGS studies. The point estimate of the effect resulted 22% (95% C.I.: [15%;31%]) in apparently isolated anomalies, 33% (95% C.I.: [22%;46%]) in CNS-only related anomalies (≥1) and 46% (95% C.I.: [38%;55%]) in non-isolated anomalies (either ≥ 2 anomalies in CNS, or CNS and extra-CNS). Meta-analysis showed a substantial diagnostic improvement in performing Prenatal Genome-Wide Sequencing analysis (Exome or Genome) over karyotype and CMA in CNS anomalies.