[Clinical features and gene analyses of six patients with MYH9-related disease].

OBJECTIVE: To investigate clinical features and to identify gene mutations in six patients with nonmuscle myosin heavy chain 9 gene (MYH9)-related disease. METHODS: The platelet counts were measured using automated complete blood cell counter and manual manner. The size of platelets and inclusion bodies were observed under light microscopy. All the 40 exons and exon-intron boundaries of MYH9 gene were amplified by PCR and then DNA sequencing was performed. Restriction endonuclease analysis and polyacrylamide gel electrophoresis (PAGE) were used for polymorphism analysis. RESULTS: Six patients all shared the common features of thrombocytopenia with giant platelets and granulocyte inclusions. Four MYH9 gene mutations were found in the six patients: T97C (W33R) in exon 1, 4335Insert CAGAAGAAG (1445InsQKK) and G4269A (D1424N) in exon 30 and G5833T (E1945Stop) in exon 40. The former two were novel mutations which have not been reported in the literature. The results of restriction endonuclease analysis and PAGE could exclude the possibility of nucleotide polymorphisms. CONCLUSIONS: The MYH9 gene mutations were identified in six patients with MYH9 related disorders, and T97C (W33R) and 4335InsCAGAAGAAG (1445InsQKK) were novel mutations. MYH9 related disease should be considered in individuals with persistent thrombocytopenia which is non-responsive to corticosteroids and immuno-repressive agents.

[Clinical and gene study of three pedigrees of phytosterolemia associated with macrothrombocytopenia and hemolysis].

OBJECTIVE: To study the clinical features and ABCG5/ABCG8 gene mutations of three pedigrees of phytosterolemia presented with macrothrombocytopenia and hemolysis. METHODS: Erythrocyte and platelet morphology were examined under light microscope. Plasma sterol levels were measured by high pressure/performance liquid chromatography method. All of ABCG5 and ABCG8 exons and intron-exon boundaries were directly sequenced to identify mutations, the corresponding gene mutation sites of three families members and healthy individuals were detected. RESULTS: All the patients presented macrothrombocytopenia, hemolysis, splenomegaly and xanthomas. The blood smears showed large platelets, some as large as erythrocytes, and abnormal erythrocyte shapes, such as stomatocytes. Plasma concentrations of phytosterols, especially sitosterol were markedly elevated (30 fold) in the affected patients. Four mutations were identified in these three pedigrees, ABCG5 C20896T (R446X) and A20883G, ABCG8 del43683-43724 and del1938C-1939G/ins1938T. The latter three were novel mutations reported for the first time. CONCLUSIONS: Phytosterolemia associated with macrothrombocytopenia and hemolysis is a new subtype of this disease. Plasma phytosterols and related gene analysis should be performed when ever an unexplained macrothrombocytopenia, especially combined with haemolysis or/and stomatocytosis.

[Analysis of clinical features and gene mutations in 6 patients with Wiskott-Aldrich syndrome].

OBJECTIVE: To investigate clinical features, laboratory alterations and gene mutations of 6 patients with Wiskott-Aldrich syndrome (WAS). METHODS: T lymphocyte subtypes were measured by flow cytometer. The routine blood tests including platelet count and mean platelet volume were performed by complete blood analyzer Sysmex XE2100. Serum immunoglobulin was measured by immunoturbidimetry. Mutations in WAS protein (WASP) gene (including all the exons and exon-intron boundaries and 3', 5' untranslation region) of 6 patients and their family members were identified by PCR and sequencing. RESULTS: The patients presented with petechiae, easy bruise, eczema, bloody diarrhea, recurrent infection and fever, and the clinical scores were 3 or 4. They were thrombocytopenia with smaller mean platelet volume, anemia and leukocytosis. Megakaryocyte number was normal or slightly increased in bone marrow. In the probands, the percentage of CD3+ T cells was decreased, the CD4+/CD8+ ratio was abnormal, while the fractions of CD19+ and CD16+ CD56+ cells were in normal range. In most of the patients, the serum levels of IgG and IgA were increased. Six mutations were identified in the patients, including 10250 C-->T, and five novel mutations: 6783 C-->G,10216-10221 Ins G, 9964 Del T,10192-10203 Del GCCTGCCGGGG and 10052-10059 del GCTACTG. The 6783 C-->G in exon 3 resulted in premature stop at Tyr102, and the remaining four mutations in exon 10 resulted in frame shift and premature stop. CONCLUSION: The main characteristics of these WAS patients were thrombocytopenia with smaller mean platelet volume and immunological disturbance. Their gene mutations were deletion, insertion or nonsense mutations. All the patients had been misdiagnosed as ITP, indicating the importance of differential diagnosis.