[Identification of nonmuscle mysin heavy chain 9 gene mutation in a May-Hegglin anomaly family].

OBJECTIVE

To describe the clinical phenotype and identify the nonmuscle myosin heavy chain 9 (MYH9) gene mutation in the first May-Hegglin anomaly family in China.

METHODS

The exons 25, 31 approximately 32 38 and 40 in the MYH9 gene of the proband and her affected father were amplified with polymerase chain reaction, and the PCR products were sequenced. After the specific point mutation in exon 38 was identified in these two cases, the corresponding region of the MYH9 gene was amplified and nuclear acid sequence analysis was conducted among 30 healthy persons, one patient with idiopathic thrombocytopenic purpura and one patient with thrombotic thrombocytopenic purpura. The CpoI restriction endonuclease map from the PCR products of exon 38 of MYH9 gene was analysed among the proband, her father and other family members, 30 normal controls, 1 ITP patient, and one TTP patient.

RESULTS

The proband and her affected father manifested a typical triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes. The patient showed mild hemorrhagic tendency since infancy, while the platelet aggregation function was normal. A 5521G --> A mutation (GAG --> AAG) in the exon 38 of the MYH9 gene existed in the proband and her affected father, resulting in a characteristic change in CpoI restriction endonuclease map.

CONCLUSION

The cases of May-Heggelin anomaly in China show typical triad of thrombocytopenia, giant platelets, and inclusion bodies in leukocytes too. Mutation of MYH9 gene exists in cases of May-Hegglin anomaly in China. The point mutation is located in exon 38 (G5521A) in this family.