Our study aimed to report the clinical features and epidemiological characteristics of hereditary transthyretin amyloidosis-polyneuropathy(ATTRv-PN) with TTR Ala97Ser(p.Ala117Ser) mutation from South Mainland China. We identified 21 patients from 20 families diagnosed with Ala97Ser ATTRv-PN based on strict clinical and electrophysiological criteria from three centers. Clinical and laboratory data were retrospectively retrieved for analysis. A gender imbalance was noted with a male-to-female ratio of 18:3. All patients showed late onset, with the age of onset at 56.5 ± 7.2 years. The predominant initial symptom, reported by 15 patients (71.4%), was numbness. Paraesthesia was present in all patients. Eighteen patients (85.7%) had autonomic dysfunction. Cardiac, renal, and ocular dysfunctions were noted in 17 (80.9%), 4(19.0%), and 4(19.0%) patients, respectively. Nerve conduction studies have shown axonal-type sensorimotor polyneuropathy. The decline in sensory nerve action potentials was more noticeable than in compound muscle action potentials. The nerve damage present in the lower limbs was more severe than that in the upper limbs. Nerve biopsy revealed positive Congo red staining in 11/15 patients (73.3%). ATTRv-PN appears relatively rare in South Mainland China, with our study providing the largest cohort of Ala97Ser mutation cases to date. We found a significant founder effect by combining the clinical and demographic characteristics. That helps us understand the gene's transmission pathway and lays the foundation for carrier screening and tertiary prevention and control. We also propose a new scoring model and demonstrate that this model allows the profiling of different genotypes of ATTRv-PN, facilitating early clinical detection and diagnosis.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder that progressively affects motor neurons. Gain-of-function mutations in serine palmitoyltransferase (SPT) genes, notably SPTLC1 and SPTLC2, have been linked to juvenile ALS. Here, we describe two childhood-onset ALS cases with distinct SPTLC2 mutations, providing new insights into sphingolipid dysregulation and its role in ALS pathogenesis. Two Chinese patients with early-onset ALS, both carrying SPTLC2 mutations, were recruited from Beijing Children's Hospital. We conducted whole-exome sequencing (WES) to identify genetic variants, followed by Sanger sequencing for validation. Sphingolipid profiles were analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Clinical evaluations included neurological assessments, brain MRI and electromyography. Additionally, mutant cell lines were established to assess the functional effects of the specific mutations. Patient 1, a 6-year-old male, exhibited a novel heterozygous de-novo SPTLC2 variant (c.197T > G, p.T66R). Patient 2, a 7-year-old female, had a recurrent heterozygous de-novo SPTLC2 variant (c.778G > A, p.E260K). Both patients showed elevated levels of specific sphingolipids compared to controls, with distinct profiles between the SPTLC2-ALS and SPTLC1-hereditary sensory and autonomic neuropathy type 1 (HSAN1) cases. The novel p.T66R mutation was predicted to alter protein interactions within the SPT complex, potentially impairing sphingolipid homeostasis. Functional studies further revealed that the p.T66R variant reduces the inhibitory regulation of SPT by ORMDL proteins, leading to unrestrained SPT activity and excess sphingolipid production. Our findings identify a novel SPTLC2 variant linked to childhood-onset ALS and reveal altered sphingolipid profiles associated with different genetic mutations. These results underscore the importance of sphingolipid metabolism in ALS and suggest potential avenues for targeted therapeutic interventions. Further research is needed to explore treatment options aimed at modulating sphingolipid levels and correcting genetic defects, as well as investigating potential biomarkers for early diagnosis.

Familial dysautonomia (FD) is characterized by skeletal morbidity, including osteoporosis and increased fracture risk. We aimed to assess bone mineral density (BMD) and trabecular bone score (TBS) in individuals with FD, and to explore correlations with disease severity. This retrospective study included all the patients with FD who performed at least one dual-energy X-ray absorptiometry (DXA) scan at our institution during 2015-2023. Demographic and clinical data obtained from medical records included: medical treatment, anthropometric measurements, Functional Severity Scale (FuSS) score, balance assessment, the Brief Ataxia Rating Scale score, ambulation ability, blood test results and fracture history. Forty-one patients (21 males) had at least one DXA scan. The median age at the first scan was 25 years (range 7-47). The mean BMD Z-score was - 1.2 ± 1.5 at the lumbar spine and - 1.3 ± 1.1 at the bilateral proximal femur. The mean TBS Z-score was - 1.8 ± 1.6. The bilateral proximal femur BMD Z-score correlated with better scores of balance (r = 0.612, p = 0.001), ambulation (r = 0.627, p = 0.001) and ataxia (r = - 0.470, p = 0.015). For 67% of the patients, C-terminal telopeptides of type I collagen (CTX) was above the normal range for age. Both CTX and procollagen type I N-terminal propeptide (P1NP) correlated negatively with FuSS (r = - 0.515, p = 0.10 and r = - 0.619, p = 0.042, respectively) and with L1-4 Z-scores (r = - 0.681, p = 0.03 and r = - 0.700, p = 0.02, respectively). Individuals with FD had low BMD and TBS Z-scores. These parameters were correlated to disease severity, specifically to balance and ambulation. The bone resorption marker was high and negatively correlated with disease severity.

Congenital insensitivity to pain with anhidrosis is a rare but devastating hereditary disease. Congenital insensitivity to pain with anhidrosis is caused by a mutation in the neurotrophic receptor tyrosine kinase 1 gene (NRTK1). The condition is characterized by multiple injuries, recurrent infections, and mental retardation. A 7-year-old Kurdish female patient, with a known case of congenital insensitivity to pain with anhidrosis, presented with a left tibial fracture, complicated by incorrect healing, osteomyelitis, and pseudoarthrosis spanning over a number of years. The osteomyelitis and pseudoarthrosis eventually healed after treatment with a combination of a long course of antibiotics, CERAMENT with gentamicin, and 40 sessions of hyperbaric oxygen treatment at 2.4 bar, 113 minutes with two air breaks. This is the first reported case of using hyperbaric oxygen treatment in children with congenital insensitivity to pain with anhidrosis. We discuss potential mechanistic explanations of the association between healing and hyperbaric oxygen treatment. Hyperbaric oxygen treatment may be considered in other cases of complicated infections or treatment-resistant pseudoarthrosis in patients with this rare disease.

Dystonin (DST), also known as bullous pemphigoid antigen 1 (BPAG1), encodes cytoskeletal linker proteins belonging to the plakin family. The DST gene produces several isoforms, including DST-a, DST-b, and DST-e, which are expressed in neural, muscle, and cutaneous tissues, respectively. Pathogenic DST mutations cause hereditary sensory and autonomic neuropathy type 6 (HSAN-VI) and epidermolysis bullosa simplex (EBS); therefore, it is important to elucidate the roles of DST isoforms in multiple organs. Recently, we have used several Dst mutant mouse strains, in which the expression of Dst isoforms is disrupted in distinct patterns, to gain new insight into how DST functions in multiple tissues. This review provides an overview of the roles played by tissue-specific DST isoforms in neural, muscle, and cutaneous tissues.