X-linked adrenoleukodystrophy (X-ALD) is the most common inherited peroxisomal disorder caused by pathogenic variants in the ABCD1 gene, leading to impaired peroxisomal β-oxidation of very-long-chain fatty acids (VLCFAs). Adrenomyeloneuropathy (AMN) is a frequent adult phenotype characterized by progressive spastic paraparesis and axonal neuropathy. We report the first case of AMN associated with a novel ABCD1 variant. Clinical, neuroradiological, biochemical, neurophysiological, and genetic evaluations were performed in a 60-year-old male presenting with gait impairment and urinary dysfunction. Brain and spinal cord MRI, nerve conduction studies, plasma VLCFA analysis, and targeted next-generation sequencing for hereditary spastic paraplegia were carried out. Functional validation included Western blot analysis on cultured skin fibroblasts. Neurological examination showed spastic paraparesis with gait impairment. Brain MRI demonstrated confluent white matter hyperintensities, while spinal MRI revealed spinal cord atrophy. Plasma VLCFA levels were markedly elevated. Genetic testing identified a previously undescribed hemizygous ABCD1 variant, c.1922G > T (p.Gly641Val), classified as likely pathogenic according to ACMG criteria. The variant was absent from public databases. Western blot analysis demonstrated absent ABCD1 protein expression in patient-derived fibroblasts, supporting the pathogenicity of the variant. We describe the first reported case of AMN associated with the novel ABCD1 c.1922G > T (p.Gly641Val) variant, expanding the mutational spectrum of X-ALD. The combination of biochemical findings and absent ALDP expression in patient-derived fibroblasts provides strong support for the pathogenicity of this previously undescribed variant. Reports integrating clinical, biochemical, genetic, and functional data may facilitate interpretation and classification of novel ABCD1 variants in clinical practice.

ABSTRACT Distal weakness requires an extensive differential diagnosis. In this case, conduction blocks indicated multifocal motor neuropathy, but immunotherapy proved ineffective. Ultimately, genetic testing revealed a sorbitol dehydrogenase mutation, highlighting the importance of combining electrophysiological findings with molecular studies in cases where the diagnosis remains unclear.

Although pathogenic variants in MECP2 are classically associated with Rett syndrome (RTT), increasing evidence suggests that they can underlie a broader spectrum of neurological phenotypes. Clinical manifestations may vary according to sex, variant type, residual protein function, and pattern of X-chromosome inactivation. We describe five unrelated individuals carrying pathogenic MECP2 variants identified through multiplex ligation-dependent probe amplification, chromosomal microarray analysis, and next-generation sequencing. Clinical, neuroradiological, neurophysiological, and molecular findings were retrospectively reviewed. Two unrelated girls carrying large de novo Xq28 deletions encompassing the entire MECP2 locus presented with mild neurodevelopmental impairment and epilepsy, but no developmental regression or classic RTT features. Both girls showed borderline cognitive functioning and normal brain MRI. A 9-year-old boy carrying a maternally inherited MECP2 frameshift variant presented with intellectual disability, autism spectrum disorder, and focal epilepsy, whereas carriers in his family exhibited milder neuropsychiatric manifestations. A 44-year-old man carrying a MECP2 missense variant presented with an early-onset spastic-ataxic syndrome, peripheral neuropathy, and cerebellar dysfunction, while a 16-year-old girl patient carrying a distinct de novo MECP2 missense variant displayed isolated mild motor incoordination and subtle cerebellar signs with preserved cognitive functioning. Our findings expand the evidence that pathogenic MECP2 variants can produce neurological phenotypes distinct from classic RTT, including mild neurodevelopmental impairment without regression, and predominantly cerebellar or spastic-ataxic manifestations associated with limited cognitive involvement. Allelic heterogeneity seems to correlate with clinical phenotypes, at least in our small cohort. In conjunction with established diagnostic criteria, these observations support testing MECP2 in a selection of atypical neurodevelopmental and movement disorder presentations.

Objectives:Biallelic variants in HSD17B4 cause D-bifunctional protein (DBP) deficiency, a disorder of peroxisomal fatty acid β-oxidation initially associated with a neonatal phenotype and early lethality. Recently, thanks to advances in genetic analyses, the clinical spectrum has expanded to include a slowly progressive adult-onset ataxic syndrome with additional features. Our aim was to describe 5 additional affected adults and to highlight the characteristic phenotype. Methods:Five affected individuals (4 from one family; 1 from a second family) were examined in our tertiary neurogenetics referral center. The core clinical manifestations consisted of a slowly progressive cerebellar ataxia, with subclinical evidence of sensorineural hearing loss and hypergonadotropic hypogonadism leading to premature ovarian failure in affected women. Genetic analysis was performed using a custom-targeted sequencing panel for genes associated with hereditary ataxias. Causative variants were confirmed by Sanger sequencing and segregated within the families. Peroxisomal investigations were performed on blood specimens. Results:In family A, the affected siblings born from consanguineous parents carried a novel homozygous HSD17B4 variant, c.557A>T (p.Asn186Ile), whereas in the proband from the other family, 2 novel compound heterozygous variants, c.652G>T (p.Val218Leu) and c.2116C>T (p.Gln706), were identified. The peroxisomal profiles were normal. Discussion:Our case series expand the phenotypic-genotypic spectrum of DBP deficiency and provide long-term follow-up data. While no disease-modifying treatments currently exist, diagnosis has implications for genetic counseling, particularly for reproductive planning in affected women.

Krabbe disease (KD) is a rare autosomal recessive lysosomal storage disorder caused by pathogenic variants in GALC. Despite accounting only for 5

Adult patients with undiagnosed genetic disorders suffer most from diagnostic delay and seldom appear in cohort studies investigating the diagnostic yield in medical genetic clinical practice. Here we present the results of the diagnostic activity performed in a referral center on 654 consecutive, unselected adult subjects presenting with molecularly unsolved conditions. More than 50% of the referred individuals were affected by syndromic or isolated intellectual disability. Different molecular approaches, including clinical/whole exome sequencing (CES/WES), chromosomal microarray analysis (CMA), and/or targeted gene or gene panel sequencing were used to analyze patients' DNA. Definitive diagnosis was obtained in over 30% of individuals. The most sensitive methodology was CES/WES, which allowed us to reach a diagnosis in over 50% of the 162 solved cases. Despite the great variety of clinical presentations, our results represent a reliable picture of the "real world" daily routine in an outpatient medical genetics clinic dedicated to diagnostic activity, and contribute to better understand the great value of a definitive molecular diagnosis in adults, either for the affected individuals and their families. This retrospective analysis demonstrates the importance of adopting a genomic-first approach within the diagnostic process for adults affected with unsolved rare conditions.

UCHL1 encodes the neuronal protein UCH-L1, which plays a critical role in protein turnover Day (Prog Neurobiol 90(3):327–362, 2010). Variants in UCHL1 have been implicated in neurodegenerative disorders and hereditary spastic paraplegia (HSP) Mi (Ageing Res Rev 6:101856, 2023); Choi et al. (J Biol Chem 279(13):13256–64, 2004); Li et al. (Ann Clin Transl Neurol 7(8):1420–8, 2020). Monoallelic loss-of-function variants have recently been linked to adult-onset hereditary spastic paraparesis with ataxia and optic atrophy (SPG79A), as well as to adult-onset ataxia with optic atrophy in the absence of pyramidal signs, highlighting the phenotypic variability associated with UCHL1 variants Marelli et al. (J Neurol 271(9):6038–44, 2024). We report two Italian brothers presenting with progressive cerebellar ataxia, who underwent comprehensive neurological examination, ophtalmological examination, brain MRI, neurophysiological testing, and genetic analysis using targeted next-generation sequencing of ataxia- and spasticity-related genes. A novel monoallelic nonsense variant in UCHL1 (c.418 C > T; p.(Gln140*)) was identified in both siblings. Clinically, patients showed predominantly ataxic symptoms, optic neuropathy and no pyramidal signs, Our study supports UCHL1 analysis in cases of autosomal dominant adult-onset cerebellar ataxia with optic atrophy, further expanding the clinical and genetic continuum between ataxic and spastic presentations.

Spastic paraplegia type 11 (SPG11) is a progressive neurological condition with no treatment. Possible involvement of abnormal ganglioside metabolism has been reported in mouse and human cells. Preclinical data in zebrafish and fruit fly models of the disease indicate that miglustat can improve biochemical parameters and locomotion. We assessed the short-term safety of oral miglustat in patients with SPG11. This was an open-label, single center, non-randomized, phase II study. All patients received miglustat orally (4 weeks 100 mg/tid and 8 weeks 200 mg/tid). The primary outcome was the frequency of adverse events (AEs), particularly and severe AEs (SAEs), emerging in the course of the study. As secondary outcomes we measured clinical severity scores, functional tests, and biomarkers at 3 and 6 months. Twelve-week treatment with miglustat was adequately tolerated, with only minor AEs and no SAEs reported. With a few exceptions, the treatment did not seem to impact neuromotor function in patients with SPG11. Although it showed an acceptable safety profile and no SAEs, miglustat did not significantly modify plasma sphingolipid and ganglioside profiles. Its potential therapeutic impact remains low.

Background/Objectives: Schuurs-Hoeijmakers syndrome (SHMS), also known as PACS1 neurodevelopmental disorder, is a rare condition characterized by intellectual disability, distinctive craniofacial abnormalities, and congenital malformations. SHMS has already been associated with variants in the PACS1 gene in 63 patients. In this study, we describe 10 new Italian SHMS patients all harboring the common de novo p.(Arg203Trp) variant. Methods: The 10 patients we studied were evaluated by clinical geneticists and child neurologists and a detailed description of clinical features was recorded. Data were then coded using the Human Phenotype Ontology (HPO) terms. The recurrent p.(Arg203Trp) variant in PACS1 was identified by clinical exome sequencing or whole exome sequencing in trio using standard methodologies. To facilitate mutation identification, we designed a new PCR-RFLP strategy adopting the endonuclease DpnII. Results: We define a detailed clinical phenotyping in patients with intellectual disability and facial characteristics (thick eyebrows, down-slanting palpebral fissures, ocular hypertelorism, low-set ears, a thin upper lip, and a wide mouth) that can help clinicians form a more efficient diagnosis of SHMS even through neuroimaging and neuropsychological evaluation. Conclusions: Our series of 10 newly affected Italian children highlights specific clinical features that may help clinicians recognize and better manage this syndrome, contributing to precision medicine approaches in medical genetics.

We aim to characterize a novel heterozygous missense variant c.1703A > G/p. (Gln568Arg) in the ALDH18A1 gene, identified in a family with autosomal dominant hereditary spastic paraplegia (HSP). We evaluated clinical, neurophysiological, genetic, fluid biomarkers, and neuroimaging expression in different family members with and without the mutation. A comprehensive multimodal evaluation was performed, including neurological examination, motor and sensory conduction studies, transcranial magnetic stimulation, targeted genetic sequencing, biomarker analysis (amino acid profiling and plasma neurofilament light chain levels (pNfL)), and brain and spinal cord MRI. Mutation pathogenicity was assessed using in silico prediction tools and confirmed by segregation analysis in family members. The index case, a 53-year-old male, presented with progressive bladder and gait disturbances, with spasticity, weakness, brisk reflexes and reduced deep sensation in the lower limbs. Neurophysiological findings confirmed corticospinal tract involvement. MRI showed selective cerebellar atrophy. Genetic analysis identified the c.1703A > G/p. (Gln568Arg) mutation in the index case and in his father, presenting with similar clinical expression. pNfL was numerically higher in mutation carriers than the healthy brother and daughter of the index case, indicating neuro-axonal damage. Amino acid profiling showed normal levels of ornithine, citrulline, arginine, and proline. This study expands the spectrum of ALDH18A1-associated HSP, highlighting a novel mutation with a relatively late-onset and mild clinical phenotype. Further functional studies and longitudinal assessments are needed to confirm the pathogenicity of this variant and its potential implications for disease progression and therapeutic strategies.

Abstract Background Tubulins are dimeric proteins expressed in all eukaryotic cells, serving as the fundamental building blocks of microtubule filaments. The TUBB4A gene encodes the protein β-tubulin. Mutations of TUBB4A have been associated with two neurodegenerative diseases with very different clinical characteristics: dystonia type 4 (DYT4) and Hypomyelination with Atrophy of the Basal Ganglia and Cerebellum (H-ABC). Several cases of patients with H-ABC or unclassified leukoencephalopathy show spastic ataxia with or without leukodystrophy in association with mutations in exon 5 of TUBB4A gene. Case presentation We report the case of a 65-year-old woman who has been complaining of progressive difficulty in walking since childhood. The neurological examination revealed, among all, a spastic gait, difficulties in standing on the toes and heels, brisk deep tendon reflexes at upper limbs, clonic patellar reflexes, brisk ankle reflexes, as well as bilateral Babinski and Hoffmann sign, brisk jaw jerk and severe lower limb spasticity. NGS studies for inherited cases of spastic paraplegia revealed a novel variant of unknown significance (VUS) (c.1249A > G, p.D417N), in TUBB4A. To the best of our knowledge, this variant has not been reported in the literature or any databases in association with these diseases. Conclusion We report the case of a patient carrying a variant of uncertain significance (VUS) of the TUBB4A gene, showing a progressive, spastic paraparesis, supporting the extension of the phenotypic spectrum up to include spastic paraplegia.

Background: Autosomal recessive inherited pathogenetic variants in the histidine triad nucleotide-binding protein 1 (HINT1) gene are responsible for an axonal Charcot-Marie-Tooth neuropathy associated with neuromyotonia, a phenomenon resulting from peripheral nerve hyperexcitability that causes a spontaneous muscle activity such as persistent muscle contraction, impaired relaxation and myokymias. Methods: Herein, we describe two brothers in whom biallelic HINT1 variants were identified following a multidisciplinary approach. Results: The younger brother came to our attention for clinical evaluation of moderate intellectual disability, language developmental delay, and some behavioral issues. His elder brother presented mild intellectual disability, hyperactivity, tiptoe walking, and gait ataxia. At first evaluation, motor impairment with frequent falls, pes cavus, and distal hyposthenia with reduced osteotendinous reflexes were found in both. Grip myotonic phenomenon was also noted. Blood tests revealed mildly elevated creatine kinase, and neurophysiology investigations revealed predominantly axonal polyneuropathy. Muscle MRI highlighted fibro-adipose infiltration, prevalent in the lower limbs. Gene panel testing detected a heterozygous HINT1 variant (c.355C>T/p.(Arg119Trp)) on the paternal allele. A further in-depth analysis using Integrative Genomics Viewer and Optical Genome Mapping led us to identify an additional variant in HINT1 represented by a complex rearrangement located in the region 5 ' UTR-exon 1-intron 1, not previously described. Conclusions: This complex rearrangement could have been overlooked if the clinical picture had not been evaluated as a whole (from a clinical, neurophysiological, and neuroimaging point of view). Neuropsychiatric manifestations (intellectual disability, hyperactivity, etc.) are part of the picture of HINT1-related neuromyotonia.

Movement Disorders Clinical PracticeEarly View LETTERS: GENOTYPE AND PHENOTYPE A Novel Compound Heterozygous Mutation in Aprataxin Causes Slowly Progressive Ataxia without Oculomotor Apraxia Sara Satolli MD, Corresponding Author Sara Satolli MD [email protected] orcid.org/0009-0008-6679-0531 Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy Correspondence to: Sara Satolli, MD, Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Viale del Tirreno, 331, 56128, Pisa, Italy. E-mail: [email protected]Search for more papers by this authorRosa De Micco MD, PhD, Rosa De Micco MD, PhD orcid.org/0000-0002-6397-8888 Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorDaniele Galatolo PhD, Daniele Galatolo PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this authorAlessandra Tessa PhD, Alessandra Tessa PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this authorMario Cirillo MD, Mario Cirillo MD Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorAlessandro Tessitore MD, PhD, Alessandro Tessitore MD, PhD Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorFilippo Maria Santorelli MD, PhD, Filippo Maria Santorelli MD, PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this author Sara Satolli MD, Corresponding Author Sara Satolli MD [email protected] orcid.org/0009-0008-6679-0531 Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy Correspondence to: Sara Satolli, MD, Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Viale del Tirreno, 331, 56128, Pisa, Italy. E-mail: [email protected]Search for more papers by this authorRosa De Micco MD, PhD, Rosa De Micco MD, PhD orcid.org/0000-0002-6397-8888 Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorDaniele Galatolo PhD, Daniele Galatolo PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this authorAlessandra Tessa PhD, Alessandra Tessa PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this authorMario Cirillo MD, Mario Cirillo MD Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorAlessandro Tessitore MD, PhD, Alessandro Tessitore MD, PhD Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Naples, ItalySearch for more papers by this authorFilippo Maria Santorelli MD, PhD, Filippo Maria Santorelli MD, PhD Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Fondazione Stella Maris, Pisa, ItalySearch for more papers by this author First published: 16 June 2024 https://doi.org/10.1002/mdc3.14132Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1Galatolo D, De Michele G, Silvestri G, et al. NGS in hereditary ataxia: when rare becomes frequent. Int J Mol Sci 2021; 6(22): 8490. 10.3390/ijms22168490 Google Scholar 2Richards S, Aziz N, Bale S, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015; 17: 405–424. 10.1038/gim.2015.30 PubMedWeb of Science®Google Scholar 3Moreira MC, Barbot C, Tachi N, et al. The gene mutated in ataxia-ocular apraxia 1 encodes the new HIT/Zn-finger protein aprataxin. Nat Genet 2001; 29: 189–193. 10.1038/ng1001-189 CASPubMedWeb of Science®Google Scholar 4Pedroso JL, Vale TC, da Costa SCG, Santos M, Alonso I, Barsottini OGP. Complex movement disorders in ataxia with oculomotor apraxia type 1: beyond the cerebellar syndrome. Tremor Other Hyperkinet Mov (N Y) 2020; 10: 39. 10.5334/tohm.557 PubMedWeb of Science®Google Scholar 5Date H, Onodera O, Tanaka H, et al. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia is caused by mutations in a new HIT superfamily gene. Nat Genet 2001; 29: 184–188. 10.1038/ng1001-184 CASPubMedWeb of Science®Google Scholar 6Renaud M, Moreira MC, Ben Monga B, et al. Clinical, biomarker, and molecular delineations and genotype-phenotype correlations of ataxia with oculomotor apraxia type 1. JAMA Neurol 2018; 1(75): 495–502. 10.1001/jamaneurol.2017.4373 Google Scholar 7Criscuolo C, Mancini P, Menchise V, Saccà F, De Michele G, Banfi S, Filla A. Very late onset in ataxia oculomotor apraxia type I. Ann Neurol 2005; 57: 777. 10.1002/ana.20463 CASPubMedWeb of Science®Google Scholar 8Ronsin S, Hannoun S, Thobois S, Petiot P, Vighetto A, Cotton F, Tilikete C. A new MRI marker of ataxia with oculomotor apraxia. Eur J Radiol 2019; 110: 187–192. 10.1016/j.ejrad.2018.11.035 PubMedWeb of Science®Google Scholar 9Wu X, Dong N, Liu Z, Tang T, Liu M. Case report: a novel APTX p.Ser168GlufsTer19 mutation in a Chinese family with ataxia with oculomotor apraxia type 1. Front Neurol 2022; 1(13):873826. 10.3389/fneur.2022.873826 Google Scholar Early ViewOnline Version of Record before inclusion in an issue ReferencesRelatedInformation

Spinocerebellar ataxias (SCAs) are characterized by substantial phenotypic variability. Among them, SCA42 is a rare non-expansion entity presenting with slowly progressive cerebellar syndrome but whose clinical spectrum may be also wider. A 53-year-old male presented with progressive myoclonus-ataxia and intellectual disability. Genetic screening revealed a novel c.3835G > A (p. Asp1279Asn) variant in the CACNA1G gene. SCA42 is a rare non-expansion SCA caused by mutations in CACNA1G on chromosome 17q21, encoding the Ca(V)3.1, a low-threshold voltage-gated T-type calcium channel. The novel variant we identified is potentially involved in channel activity. This case expands the knowledge regarding CACNA1G-associated phenotype and highlights the importance of genetic screening in myoclonus-ataxia disorders.

Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) and disease spectrum is an autosomal recessive disorder associated with biallelic repeat expansion (RE) in the RFC1 gene. A high carrier frequency in the healthy population determines the possibility of having affected members in two consecutive generations. We describe pseudodominance in two families affected with RFC1 disorder (10 affected, 5 oligo/asymptomatic individuals). In Family A, after the 75-year-old index case was diagnosed with CANVAS, the 73-year-old wife decided to undergo screening for carrier testing. Although she did not report any symptoms, she resulted positive for the biallelic AAGGG RE thus leading to a diagnosis in the asymptomatic offspring as well and revealing a pseudodominant pattern of inheritance. In Family B pseudodominance was suspected after the identification of the RFC1 RE in the proband affected by sensitive neuropathy because of a positive family history for undetermined polyneuropathy in the mother. The post-mortem identification of the RFC1 RE in a sample specimen from the deceased mother, who had been under our care, allowed the solution of a "cold case". Our report suggests that pseudodominance is a confounding phenomenon to consider in RFC1-spectrum disorder and genetic counselling is instrumental in families with affected individuals.