Objective:To explore the hematological phenotype and genotypic characteristics of five Chinese individuals with a rare thalassemia mutation HBB: c. 93-21G>A. Methods:A retrospective study was carried out on five individuals identified by the People′s Hospital of Yangjiang and Guangzhou Hybribio Co., Ltd. from May 2018 to September 2022. Routine blood test and hemoglobin electrophoresis were performed, and the genotypes of five subjects were determined by using PCR combined with reverse dot blotting (RDB), nested PCR, Gap-PCR and Sanger sequencing. This study was approved by Medical Ethics Cornmittee of the People′s Hospital of Yangjiang (Ethics No. 20240001).Results:Among the five individuals, hematological data of one was unavailable, and the remaining four had presented with microcytosis and hypochromia. The results of hemoglobin electrophoresis indicated that all of them had a HbA 2 level of ≥4.7%. Genetic analysis showed that one case had harbored compound heterozygous mutations of ααα anti3.7 triplet and HBB: c. 93-21G>A, one had compound heterozygous mutations of -α 3.7 and HBB: c. 93-21G>A, whilst the remaining three were heterozygous for the HBB: c. 93-21G>A mutation. Conclusion:The hematological phenotype of β-thalassemia carriers ( HBB: c. 93-21G>A) is similar to that of other β + thalassemia heterozygotes with mild β-thalassemia characteristics.

Objective: To investigate the role of lysosomes in manganese-induced toxicity in human neuroblastoma SK-N-SH cells. Methods: SK-N-SH cells were treated with MnCl₂ at doses of 0.062 5, 0.125, 0.25, 0.5, 1.0, 2.0 and 4.0 mmol/L for 24 h, and the cell viability was detected by MTT assay. Cells were treated with MnCl₂ at doses of 0.125, 0.25, 0.5 and 1.0mmol/L for 24 h, and lysosomes labeled with lysotracker red were observed by laser confocal microscopy, the expression levels of LAMP1 and CTSD were detected by western blot, and CTSD activity was detected by Cathepsin D Activity Fluorometric Assay Kit. Results: Compared with the control group, the survival rates of SK-N-SH cells were decreased significantly in the 0.5-4.0 mmol/L MnCl₂ treatment groups (P<0.01) , the relative fluorescence intensities of 0.5 and 1.0 mmol/L MnCl₂ treatment groups were increased (P<0.01) . Compared with the control group, the 0.125-0.5 mmol/L MnCl₂ treatment groups had significant increase in the the expression of LAMP1 (P<0.01) . Compared with the control group, the expression of m-CTSD was significantly increased at the does of 0.125-0.25 mmol/L MnCl₂, while it was decreased at the does of 1.0 mmol/L (P<0.01) . Otherwise, it wasn’t observed significant difference of the activity of CTSD between different MnCl₂ treatment groups. Conclusion MnCl₂ could cause cytotoxicity in SK-N-SH cells. Lysosomes may play a normal function at low doses of manganese, but they may be damaged at high doses of manganese. As an organelle that can degradate substrates in autophagy, lysosomes participate in the neurotoxic mechanism of manganese.