Neurology-Genetics最新文献

Background and objectives: Primary hypokalemic periodic paralysis (HypoPP) is a muscle channelopathy that can cause periodic paralysis and permanent weakness. Currently, little is known about how progressive this myopathy is. Natural history data for HypoPP can potentially answer the question of progressiveness and form the basis for outcome measures to be used in follow-up and emerging treatment trials. We aimed to describe the natural history of HypoPP and assess whether quantitative fat imaging is a valuable biomarker to monitor disease progression.

Methods: In this prospective follow-up study, we examined disease progression using Dixon MRI to monitor changes in fat replacement of the muscle and stationary dynamometry to monitor changes in muscle strength.

Results: We included 37 persons (mean age 43 years, range 18-79 years) with HypoPP-causing variants in CACNA1S. Three participants were asymptomatic carriers, 22 had periodic paralysis, 3 had permanent weakness, and 9 had periodic paralysis in combination with permanent weakness. The median follow-up time was 20 months (range 12-25). We found that fat fraction increased in 10 of 21 examined muscles. An increase in the composite fat fraction of at least 1 muscle group was found in all symptomatic phenotypes. By contrast, we found no significant change in muscle strength.

Discussion: The results from this follow-up study support the use of quantitative muscle MRI to monitor subclinical disease progression in HypoPP in patients with and without attacks of paralysis.

Objectives: In adults, inborn metabolic diseases are often missed in routine diagnostic settings due to a low level of suspicion.

Methods: A patient in their twenties was admitted for an apparent acute exacerbation of anxiety disorder. Medical treatment was unsuccessful, and presumed catatonic psychosis was treated by electroconvulsive treatment. The patient was referred to neurology with reduced level of consciousness, mutism with no targeted movements, obvious anxiety and tetraspasticity, eczema, and reduced body weight.

Results: EEG was normal; repeat brain MRI showed progressive atrophy and leukoencephalopathy. Autoimmune encephalitis was assumed and treated with plasma exchange, high-dose glucocorticoids, and intravenous immunoglobulin. Repeated CSF analyses remained normal. Metabolic workup showed hyperaminociduria, low neutral amino acids, and undetectable tryptophane. Whole-exome sequencing and segregation analysis revealed compound heterozygous, pathogenic and a novel, likely pathogenic variant in the SLC6A19 gene: c.718C>T, p.(Arg240*) and c.170G>A, p.(Arg57His). Diagnosing Hartnup disease, high-protein diet, and niacin supplementation led to rapid considerable improvement. At 4 months, plasma amino acids were normal; communication and behavior were age-adequate; and spasticity had almost resolved, but polyneuropathy was unchanged.

Discussion: Metabolic workup and whole-exome sequencing are recommended in rapidly progressive neuropsychiatric disease, especially with additional neurologic signs and when standard treatment fails.

Objectives: To describe a novel familial variant of superoxide dismutase 1 (SOD1)-associated amyotrophic lateral sclerosis (ALS) in a Lithuanian family, highlighting its variable progression and implications for treatment inclusion criteria.

Methods: This study presents the clinical and genetic findings of a family with the novel SOD1 variant, including one member diagnosed with early-onset ALS (onset <40 years) and one with a particularly rapidly progressing course of ALS.

Results: The SOD1 variant NM_000454.5:c.446T>C, NP_000445.1:p.(Val149Ala) was identified in affected family members and 4 asymptomatic members aged 32-56 years. We present detailed disease course of the affected family members obtained during follow-up. Clinically, this variant is associated with variable disease progression, with the time from symptom onset to death ranging from 5 to 77 months.

Discussion: The novel SOD1 variant p.Val149Ala in this Lithuanian family causes ALS of variable onset and course, including a case of early-onset ALS and one case of rapidly progressing ALS, necessitating recognition by the scientific community and development of tailored therapeutic approaches.

Objectives: To describe a case of spinocerebellar ataxia presenting with progressive apraxia of speech (AOS).

Methods: A 54-year-old man with progressive speech changes was seen clinically and referred to our observational research program on degenerative speech and language disorders. He underwent detailed speech-language and neurologic assessments and multimodal neuroimaging studies. Three board-certified speech-language pathologists, blinded to other study data, reached a consensus speech diagnosis.

Results: The patient reported 2 years of progressive speech changes against a background of mild imbalance. Speech alternating and sequential motion rates were regular but moderately slow. He segmented syllables, most prominently during repetition of multisyllabic words, and had decreased prosodic variation in connected speech. He was diagnosed with prosodic-predominant primary progressive AOS. He had mild extremity ataxia and difficulty with tandem gait on neurologic examination. MRI showed marked pontine-cerebellar atrophy. FDG-PET showed premotor area and posterior fossa hypometabolism. Genetic testing revealed cytosine-adenine-guanine repeat expansion in the ATXN2 gene, consistent with spinocerebellar ataxia type 2 (SCA2).

Discussion: SCA2 is an autosomal dominant, degenerative disease characterized by cerebellar ataxia, including ataxic dysarthria. Our case demonstrates that SCA2 can manifest with progressive AOS. Neuroimaging supported involvement of areas classically associated with AOS.

[This corrects the article DOI: 10.1212/NXG.0000000000200175.].

Background and objectives: Tibial muscular dystrophy (TMD) is an autosomal dominant, slowly progressive late-onset distal myopathy. TMD was first described in 1991 by Udd et al. in Finnish patients, who were later found to harbor a heterozygous unique 11-bp insertion/deletion in the last exon of the TTN gene-the Finnish founder variant (FINmaj). In homozygous state or compound heterozygosity with a truncating variant, the FINmaj causes early-onset recessive titin-related limb-girdle muscular dystrophy type 10 (LGMD R10). So far, the FINmaj variant has not been detected outside the Finnish population.

Methods: We describe an Estonian family presenting both early-onset LGMD R10 and late-onset TMD. The index patient underwent trio exome sequencing (ES), muscle biopsy, and RNA sequencing. The detected variants were validated by Sanger sequencing. Muscle MRI was performed in all affected individuals.

Results: Trio ES revealed 2 heterozygous variants in the TTN gene: (NM_001267550.2):c.107780_107790delinsTGAAAGAAAAA, p.(Glu35927_Trp35930delinsValLysGluLys) (FINmaj variant, paternally inherited) and (NM_001267550.2):c.64672+2dup (maternally inherited) in trans in the proband. Familial segregation analysis revealed the same biallelic variants in the younger affected sister and heterozygous FINmaj in the father. We characterized the effect of the splice variant by RNA sequencing, proving that it causes an intronic retention resulting in a premature stop codon. Muscle histology of the proband showed myopathic changes. Muscle MRI of both individuals with LGMD R10 showed early degenerative changes in tibialis anterior and in hypotrophy of distal hamstrings. Muscle MRI of the father with TMD, at the age of 38 years, showed early minimal fatty degeneration in the peroneus longus and right tibialis anterior muscles.

Discussion: For the first time, we have detected the FINmaj variant in the Estonian population. We report an Estonian family without any known Finnish ancestry for many generations, with 2 siblings harboring FINmaj in a compound with a splice site variant and their father with heterozygous FINmaj. It is currently not known whether the FINmaj is originally Estonian or Finnish ancestry. Further population studies in Estonia to establish the frequency of FINmaj in the population are ongoing and will solve the quest.

Tay-Sachs disease is a neurodegenerative disorder characterized by progressive neurologic impairment due to pathogenic variants in the HEXA gene that codes for the alpha subunit of β-hexosaminidase. We report 2 cases of adult-onset progressive weakness, ataxia, and neuropsychiatric symptoms in a 30-year-old man and 37-year-old woman. Both patients had compound heterozygosity in the HEXA gene with 4 distinct variants. The first patient had subsequent confirmatory functional enzyme testing displaying reduced hexosaminidase concentration, and the second patient had functional enzyme testing before genetic testing, exemplifying alternative avenues for the diagnosis of late-onset Tay-Sachs (LOTS) disease.

Although X-linked adrenoleukodystrophy (ALD) has historically been considered a childhood disease managed by pediatric neurologists, it is one of the most common leukodystrophies diagnosed in adulthood. An increase in both male and female adults reaching diagnosis due to familial cases identified by state newborn screening panels and more widespread use of genetic testing results in a large cohort of presymptomatic or early symptomatic adults. This population is in urgent need of standardized assessments and follow-up care. Adults with ALD/adrenomyeloneuropathy (AMN) may be diagnosed in a variety of ways, including after another family member is identified via genetic testing or newborn screening, presenting for symptomatic evaluation, or following diagnosis with primary adrenal insufficiency. Significant provider, patient, and systems-based barriers prevent adult patients with ALD/AMN from receiving appropriate care, including lack of awareness of the importance of longitudinal neurologic management. Confirmation of and education about the diagnosis should be coordinated in conjunction with a genetic counselor. Routine surveillance for adrenal insufficiency and onset of cerebral ALD (CALD) in men should be performed systematically to avoid preventable morbidity and mortality. While women with ALD do not usually develop cerebral demyelination or adrenal insufficiency, they remain at risk for myeloneuropathy and are no longer considered "carriers." After diagnosis, patients should be connected to the robust support networks, foundations, and research organizations available for ALD/AMN. Core principles of neurologic symptom management parallel those for patients with other etiologies of progressive spastic paraplegia. Appropriate patient candidates for hematopoietic stem cell transplant (HSCT) and other investigational disease-modifying strategies require early identification to achieve optimal outcomes. All patients with ALD/AMN, regardless of sex, age, or symptom severity, benefit from a multidisciplinary approach to longitudinal care spearheaded by the neurologist. This review proposes key strategies for diagnostic confirmation, laboratory and imaging surveillance, approach to symptom management, and guidance for identification of appropriate candidates for HSCT and investigational treatments.