A family of Niemann-Pick disease type C caused by compound heterozygous mutations in NPC1 gene / 中华神经科杂志

Objective:To report the clinical and genetic characteristics of a family with Niemann-Pick disease type C caused by novel compound heterozygous mutations in the NPC1 gene to improve the clinicians′ recognition of the disease. Methods:Two patients from the family with non-consanguineous marriages admitted to the Department of Neurology of the First Affiliated Hospital of Kunming Medical University in 2020 were examined in detail. Peripheral blood DNA was extracted, and whole exome sequencing was performed on the patients, combined with Sanger sequencing for verification. The mutation and protein function predictor softwares were applied to analyze the mutation sites.Results:The inheritance was autosomal recessive in this family. The onset age of the proband was 9 years, and the main clinical manifestations were dysarthria, dysphagia, cognitive impairment, ataxia, bilateral pyramidal tract impairment, vertical supranuclear gaze palsy and splenomegaly. The clinical phenotype of the proband′s younger brother was similar to that of the proband, but it was more severe than that of the proband. The younger brother of the proband had an earlier age of onset and severe psychomotor retardation. Whole exome sequencing showed that both brothers carried 2 rare variants of NPC1 gene:1 pathogenic, stop gain at c.352_353del, p.Gln119ValfsTer8, and a missense change, c.593A>G, p.Asn198Ser, of suspected pathogenic. Sanger sequencing confirmed that compound heterozygous mutations were derived from the proband′s parents. According to the American College of Medical Genetics and Genomics guidelines, the above variants were rated as pathogenic and suspected pathogenic, respectively. And the c.593A>G, p.Asn198Ser mutation found in this family was a novel one which had not been reported yet. The proband had delayed diagnosis for 7 years from the onset of symptoms. After taking megastat for 1 year, the symptoms of dysphagia, ataxia and vertical eye movement disorder were significantly improved. Conclusions:The clinical phenotype of the pedigree was consistent with the clinical phenotype of Niemann-Pick disease type C. Compound heterozygous mutations of NPC1 gene (c.352_353del; c.593A>G) were found to be the genetic cause of the family.

Novel compound heterozygous mutation in NPC1 gene cause Niemann–Pick disease type C with juvenile onset

Niemann–Pick disease type C (NPC) is a progressive lysosomal storage disorder caused by mutations in the NPC1 (in 95% of cases) or NPC2 (in *5% of cases) genes, inherited in an autosomal recessive manner. We report the case of a 38-year-old woman with learning disorder from her first year of schooling, and could notice slow progressed cognitive impairment, social withdrawal, apathy, handwriting alterations, deterioration of language skills and dysphagia. Brain magnetic resonance imaging showed severe cerebellar atrophy, hypoplasia of the corpus callosum, asymmetric lateral ventricular enlargement, and severe enlargement of frontal and parietal subarachnoid spaces. Next generation sequencing for NPC genes (NPC1 and NPC2) detected compound heterozygous mutations in NPC1 gene, including c.1553G [A (p.Arg518Gln), paternally inherited, and c.1270C [ T (p.Pro424Ser) maternally inherited. The first mutation has been already described in literature and correlated to NPC, while the second mutation is still unknown. Moreover, filipin test and quantification of plasma oxysterols confirmed NPC diagnosis. We can suggest the missense mutation c.1270C [ T (p.Pro424Ser) as a new causative mutation of NPC

Immune system dysfunction in Niemann-Pick type C1 mice / 中华微生物学和免疫学杂志

Objective To analyze the differences in immune system between Npc1 gene mutant (Npc1-/ -) and wild-type (Npc1+/ +) mice for better understanding the pathogenesis of Niemann-Pick disease type C1 (NPC1) from an immunological perspective and providing reference for NPC1 treatment in clinic.Methods Body, thymus and spleen weight of Npc1-/ -and Npc1+/ + mice aged (14±2) days, (42±2) days and (63±2) days (Day14±2 , Day42±2 and Day63±2 ) were recorded and the associated organ index were calcu-lated. White blood cell count in peripheral blood of mice aged Day42±2 was examined by routine blood test. Expression of cytokines at mRNA level in mouse peripheral blood was detected by qPCR. Percentages of CD4+, CD8+ and CD19+ lymphocytes in peripheral blood and spleen of mice aged Day42±2 were measured by flow cytometry. Apoptosis and senescence of spleen in mice aged Day63±2 were examined by immunofluores-cence and β-galactosidase staining. Results Compared with Npc1+/ + mice, there was no significant differ-ence in the weight of spleen and thymus in Npc1-/ - mice aged Day14±2; the weight of spleen in Npc1-/ - mice aged Day42±2 significantly increased, but the weight of thymus showed a significant decrease; furthermore, both the weight of spleen and thymus in Npc1-/ - mice aged Day63±2 significantly decreased; and the body weight of Npc1-/ - mice of each age group significantly decreased. Moreover, compared with Npc1+/ + mice, the absolute number of lymphocytes in the peripheral blood of Npc1-/ - mice aged Day42±2 showed no signifi-cant difference, but the percentage in whole white blood cells significantly decreased due to the significantly increased neutrophils. Expression of cytokines ( IL-1, IL-2, IFN-γ, TNF-α, IL-4, granzyme A and granzyme B) at mRNA level in the peripheral blood leukocytes of Npc1-/ - mice aged Day42±2 was abnormal as compared with that in Npc1+/ + mice. The number of T (CD4+ and CD8+) lymphocytes in Npc1-/ - mice aged Day42±2 significantly decreased, while the number of B (CD19+) lymphocytes increased significantly as com-pared with those in the Npc1+/ + mice. Compared with Npc1+/ + mice, apoptosis and senescence of the spleen in Npc1-/ - mice aged Day63±2 aggravated significantly. Conclusion The abnormal lipid metabolism triggered by Npc1 gene mutation causes severe immune dysfunction in Npc1-/ - mice. Therefore, immune dysfunction should be taken into full consideration when treating patients with NPC1, which might help improve the life quality and prolong the survival time.

Renal function and pathological changes in Niemann-Pick disease type C1 mice / 中国病理生理杂志

AIM:To investigate the renal function and pathological changes in Npc1 mutant ( Npc1-/-) mice. METHODS:Different genotypes of Niemann-Pick disease type C1 (Npc1) mice were identified by PCR.Subsequently, the renal function of Npc1-/-and Npc1 +/+mice at postnatal day 60 ( P60) was evaluated by measuring the activity and con-tent of important indicators in the serum including ALT , AST, LDH, urea, UA and Cr.Furthermore,β-galactosidase stai-ning and Masson staining were performed to examine the aging and fibrosis of the renal tissues , respectively .RESULTS:Compared with the Npc1 +/+mice, the body weight and kidney weight had a significant reduction ( P<0.01) in the Npc1-/-mice.The results of hepatic and renal functions showed that the activities of ALT , AST and LDH, and contents of urea, UA and Cr had marked increases (P<0.05) in the Npc1-/-mice.Moreover, the results of senescence-associatedβ-galacto-sidase staining in the renal tissues demonstrated accelerated aging in the Npc1-/-mice (P<0.01), and these results were confirmed by Masson staining, which clearly showed the formation of collagen fibers (P<0.01).CONCLUSION:Muta-tion of the Npc1 gene results in abnormal lipid metabolism , which accelerates kidney senescence by promoting fibrosis in the renal tissue and subsequently causes reduction in renal function .

Niemann-Pick disease type C: a case series of Brazilian patients / Doenca de Niemann-Pick tipo C: serie de casos de pacientes brasileiros

The aim of the study was to analyze a series of Brazilian patients with Niemann-Pick disease type C (NP-C). Method Correlations between clinical findings, laboratory data, molecular findings and treatment response are presented. Result The sample consisted of 5 patients aged 8 to 26 years. Vertical supranuclear gaze palsy, cerebellar ataxia, dementia, dystonia and dysarthria were present in all cases. Filipin staining showed the “classical” pattern in two patients and a “variant” pattern in three patients. Molecular analysis found mutations in the NPC1 gene in all alleles. Miglustat treatment was administered to 4 patients. Conclusion Although filipin staining should be used to confirm the diagnosis, bone marrow sea-blue histiocytes often help to diagnosis of NP-C. The p.P1007A mutation seems to be correlated with the “variant” pattern in filipin staining. Miglustat treatment response seems to be correlated with the age at disease onset and disability scale score at diagnosis. .

O objetivo desse estudo foi analisar uma série de casos de pacientes brasileiros com doença de Niemann-Pick tipo C (NP-C). Método Correlação entre manifestações clínicas, alterações laboratoriais, estudo molecular e resposta ao tratamento foram realizadas. Resultado A amostra consiste de 5 pacientes com idade entre 8 e 26 anos. Paralisia do olhar vertical supranuclear, ataxia cerebelar, demência, distonia e disartria estavam presentes em todos os casos. Coloração de filipina na cultura de fibroblastos mostrou padrão “clássico” em dois pacientes e padrão “variante” em três casos. O estudo molecular encontrou mutações no gene NPC1 em todos os alelos. O tratamento com miglustate foi realizado em 4 pacientes. Conclusão Embora coloração de filipina seja utilizada para confirmar o diagnóstico, o histiócito azul-marinho no aspirado de medula óssea frequentemente auxilia a confirmar o diagnóstico de NP-C. A mutação p.P1007A está correlacionada com o padrão “ variante” na coloração de filipina. A resposta ao tratamento com miglustate parece estar correlacionada com a idade e escore de desabilidade no momento do diagnóstico. .