Expanding SPTAN1 monoallelic variant associated disorders: From epileptic encephalopathy to pure spastic paraplegia and ataxia

PURPOSE

Nonerythrocytic αII-spectrin (SPTAN1) variants have been previously associated with intellectual disability and epilepsy. We conducted this study to delineate the phenotypic spectrum of SPTAN1 variants.

METHODS

We carried out SPTAN1 gene enrichment analysis in the rare disease component of the 100,000 Genomes Project and screened 100,000 Genomes Project, DECIPHER database, and GeneMatcher to identify individuals with SPTAN1 variants. Functional studies were performed on fibroblasts from 2 patients.

RESULTS

Statistically significant enrichment of rare (minor allele frequency < 1 × 10-5) probably damaging SPTAN1 variants was identified in families with hereditary ataxia (HA) or hereditary spastic paraplegia (HSP) (12/1142 cases vs 52/23,847 controls, p = 2.8 × 10-5). We identified 31 individuals carrying SPTAN1 heterozygous variants or deletions. A total of 10 patients presented with pure or complex HSP/HA. The remaining 21 patients had developmental delay and seizures. Irregular αII-spectrin aggregation was noted in fibroblasts derived from 2 patients with p.(Arg19Trp) and p.(Glu2207del) variants.

CONCLUSION

We found that SPTAN1 is a genetic cause of neurodevelopmental disorder, which we classified into 3 distinct subgroups. The first comprises developmental epileptic encephalopathy. The second group exhibits milder phenotypes of developmental delay with or without seizures. The final group accounts for patients with pure or complex HSP/HA.

Examining the Use of Radiation Therapy for Cholangiocarcinoma: Benefits through Modern Techniques

BACKGROUND

Cholangiocarcinoma (CCA) is a rare malignant tumor of the bile duct epithelium. At first diagnosis, only a minority of patients are eligible for surgery, which is regarded as the only curative treatment. This study examines the role of radiation therapy (RT) and chemoradiotherapy (CRT) in the definitive and adjuvant treatment situation.

METHODS

The monocentric, retrospective analysis included 39 patients with CCA undergoing 53 RT courses. Data were collected from January 2005 to September 2018. There were 11 cases of CRT, 6 of which were definitive. Surgery was either palliative (n = 6) or radical (n = 15).

RESULTS

After RT, the median overall survival (OS) was 10.4 months (m), median progression-free survival was 5.6 m, and median duration of local control (DOLC) was 8.9 m. There was a significant difference in survival between patients with and without locoregional lymph node metastasis (OS: 4.3 vs. 15.4 m, p = 0.031). After treatment of a primary tumor, DOLC was about twice as long as in the recurrent situation (10.4 vs. 5.4 m, p = 0.032). Conservative therapy significantly elevated the risk of local recurrence compared to radical surgery in univariate and multivariate analyses. Side effects were mostly classified as mild to moderate. Termination of RT and increased alanine aminotransferase were significantly less frequent after stereotactic body radiation therapy and hypofractionation.

CONCLUSION

RT can achieve local control in patients with CCA. Toxicities of RT are manageable but require close clinical and laboratory follow-up.