Advances in the diagnosis of acid sphingomyelinase deficiency / 中国医师杂志

Acid sphingomyelinase deficiency (ASMD), also known as type A and B Niemann-Pick disease, is a group of intra-lysosomal lipid storage diseases caused by mutations in the SMPD1 gene that decrease acid sphingomyelinase activity or even cause deletion, resulting in abnormal deposition of sphingolipids. This disease can be diagnosed by bone marrow aspiration, pathological biopsy, acid sphingomyelinase activity measurement and SMPD1 gene testing. In recent years, with the rapid progress of molecular diagnostic techniques, new insights have been gained in the laboratory diagnosis of ASMD by means of molecular genetic tests, biomarkers and acid sphingomyelinase activity assay. This article will review the diagnostic progress of ASMD, aiming to reduce the misdiagnosis and leakage of the disease and improve the clinicians′ understanding of the disease.

Niemann-Pick disease type B: HRCT assessment of pulmonary involvement / Doença de Niemann-Pick tipo B: avaliação do comprometimento pulmonar por TCAR

ABSTRACT Objective: To analyze HRCT findings in patients with Niemann-Pick disease (NPD) type B, in order to determine the frequency of HRCT patterns and their distribution in the lung parenchyma, as well as the most common clinical characteristics. Methods: We studied 13 patients (3 males and 10 females) aged 5 to 56 years. HRCT images were independently evaluated by two observers, and disagreements were resolved by consensus. The inclusion criteria were presence of abnormal HRCT findings and diagnosis of NPD type B confirmed by histopathological examination of a bone marrow, lung, or liver biopsy specimen. Results: The most common clinical findings were hepatosplenomegaly and mild to moderate dyspnea. The most common HRCT patterns were smooth interlobular septal thickening and ground-glass opacities, which were both present in all patients. Intralobular lines were present in 12 patients (92.3%). A crazy-paving pattern was observed in 5 patients (38.4%), and areas of air trapping were identified in only 1 case (7.6%). Pulmonary involvement was bilateral in all cases, with the most affected area being the lower lung zone. Conclusions: Smooth interlobular septal thickening, with or without associated ground-glass opacities, in patients with hepatosplenomegaly is the most common finding in NPD type B.

RESUMO Objetivo: Analisar os achados de TCAR em pacientes com doença de Niemann-Pick (DNP) tipo B a fim de avaliar a frequência dos padrões tomográficos e sua distribuição no parênquima pulmonar, além das características clínicas mais frequentes. Métodos: Foram estudados 13 pacientes (3 do sexo masculino e 10 do sexo feminino) com idades variando de 5 a 56 anos. As imagens de TCAR foram avaliadas por dois observadores de forma independente, e os casos discordantes foram resolvidos por consenso. Os critérios de inclusão foram presença de anormalidades na TCAR e diagnóstico confirmado de DNP tipo B por exame anatomopatológico através de biópsias de medula óssea, pulmão ou fígado. Resultados: Os achados clínicos mais comuns foram hepatoesplenomegalia e dispneia leve a moderada. Os padrões tomográficos mais frequentes foram espessamento liso de septos interlobulares e opacidades em vidro fosco, presentes em todos os pacientes. Linhas intralobulares estiveram presentes em 12 pacientes (92,3%). O padrão de pavimentação em mosaico foi observado em 5 pacientes (38,4%). Áreas de aprisionamento aéreo foram identificadas em 1 dos casos (7,6%). O comprometimento pulmonar foi bilateral em todos os casos, sendo o terço inferior dos pulmões a região mais envolvida. Conclusões: O achado de espessamento liso de septos interlobulares, com ou sem opacidades em vidro fosco associadas, em pacientes com hepatoesplenomegalia é o achado mais frequente na DNP tipo B.

Diagnosis of patients with Niemann-Pick disease type C and identification of 2 noval mutations in NPC1 gene / 中华神经科杂志

Objective To established a diagnostic methods to idenfity Niemann-Pick disease type C (NPC) in China. Methods Two patients aged 5 and 20 years respectively who presented progressive neurologic regression and splenomegaly were subjected to filipin staining of cultured skin fibroblasts and genetic analyses of NPC1 gene. Results Although there were differences in onset ages and clinical presentations, filipin staining of the cultured skin fibroblasts confirmed the clinical diagnosis of NPC, showing an intense punctate pattern of fluorescence concentrating around the nuclei, consistent with the accumulation of unesterified cholesterol in NPC cells. Genetic sequence analysis further verified the results of filipin staining. The case 1 was compound heterozygous for M1142T(3425T＞C),R1186H(3557T＞C)and case 2 for Q88H(264G＞T),469_470insGT.The latter 2 mutations were novel, and the possibility of polymorphisms was not supposed by analyzing 134 DNA samples obtained form normal controls. Conclusions Filipin stainning of the cultured skin fibroblasts is a reliable method to clinically diagnose NPC with a sensitivity. Genetic diagnose should be performed where genetic analysis is allowed.