RESUMO
Non-muscle myosin heavy chain 9-related disease (MYH9-RD) is an autosomal dominant disease caused by the mutations of the MYH9 gene encoding the non-muscle mysoin heavy chain ⅡA and leads to abnormal accumulation of myosin in cells. These further causes functional disorders of the blood, eye, ear, kidney, and liver systems. MYH9-RD displays heterogeneous kidney involvement and outcomes, but doctors still lack understandings of the mechanism and treatment strategies, owing to difficulty of conducting renal biopsies. Here, we report a case of MYH9-RD with tail fragments heterozygous mutation, which renal pathology is presented as glomerular minor lesion. Moreover, we reviewed related relevant to strengthen clinical diagnosis and understanding of MYH9-RD.
RESUMO
La trombocitopenia como motivo de consulta, requiere la búsqueda intencionada de orientar manifestaciones extrahematológicas. La megacariogénesis pasa por distintas etapas dependientes de la interacción de varios genes, entre ellos el MYH9, cuya expresión permite una adecuada formación y migración de las proplaquetas al ser liberadas al torrente sanguíneo, al mismo tiempo, existen estructuras con fisiología similar a nivel de citoesqueleto (podocitos, cilios cocleares, etc.) que podrían vincular a datos de pérdida de audición, enfermedad renal, cataratas y elevación de enzimas hepáticas conllevando a una enfermedad relacionada al gen MYH9. Se presenta el caso de un adolescente, de sexo masculino, con trombocitopenia recurrente, con el antecedente de padre con coagulopatía inespecífica, pérdida de audición, falla renal crónica, quien falleció a los 34 años por hemorragia intraparenquimatosa y edema cerebral severo, en quien se identifica una variante patogénica en heterocigosis en el gen MYH9, poniendo en relevancia la expresividad variable y efectos pleiotrópicos de este gen.
Thrombocytopenia as a reason for consultation requires an intense search to guide extrahematological manifestations. Megakaryogenesis goes through different stages depending on the interaction of several genes, including MYH9, whose expression allows proper formation and migration of proplatelets when released into the bloodstream, at the same time, there are structures with similar physiology at the cytoskeleton level (podocytes, cochlear cilia, etc.) that could be linked to data on hearing loss, kidney disease, cataracts and elevated liver enzymes leading to a disease related to the MYH9 gene. We present the case of an adolescent, male, with recurrent thrombocytopenia, with a history of a father with nonspecific coagulopathy, hearing loss, chronic kidney failure, who died at the age of 34 due to intraparenchymal hemorrhage and severe cerebral edema, in whom identifies a heterozygous pathogenic variant in the MYH9 gene, highlighting the variable expressivity and pleiotropic effects of this gene.
Assuntos
TrombocitopeniaRESUMO
Objective@#To explore the molecular basis for a pedigree affected with May-Hegglin anomaly (MHA).@*Methods@#Peripheral blood samples were collected and subjected to DNA extraction. Exons 1, 10, 16, 24, 25, 26, 30, 31, 33, 38 and 40 and flanking sequences of the MYH9 gene were subjected to PCR amplification and Sanger sequencing. Changes in protein expression were determined by an indirect immunofluorescence assay. Platelet aggregation function of the proband was assessed by thromboelastogram.@*Results@#The proband and his second son both carried a heterozygous 5521G>A (GAG→AAG) missense variant in exon 38 of the MYH9 gene, leading to p. Glu1841Lys substitution at position 1841 of amino acid sequence. Immunofluorescence showed inclusions containing NMMHC-ⅡA. Thromboelastogram suggested enhanced platelet aggregation function of the proband.@*Conclusion@#The c. 5521G>A variant of MYH9 gene has co-segregated with the phenotype of MHA in this pedigree. To assess the aggregation function of platelet by thromboelastogram can predict the risk of bleeding in MHA patients.
RESUMO
May-Hegglin anomaly (MHA) is a myosin-heavy-chain-9 (MYH9)-related disorder characterized by thrombocytopenia with giant platelets and inclusion bodies in leukocytes. MHA does not require treatment, but it may be misdiagnosed as immune thrombocytopenic purpura (ITP) and inappropriately managed. Reported herein is a case of a 12 year old female patient diagnosed as MHA with laboratory findings of severe thrombocytopenia and giant platelets in peripheral blood morphology, and followed up until 23 years of age. The patient had been diagnosed with ITP and treated with intravenous gamma-globulin therapy at another hospital, and showed no improvements in platelet count. She was then referred to our hospital for further diagnostic workup and followed up for 11 years, showing platelet count of 6,000-20,000/µL and prolonged platelet function test. She was occasionally treated with iron therapy due to iron-deficiency anemia. In 2014, we conducted a DNA analysis that revealed c.4339G>T(p.Asp1447Tyr), a known mutation of MYH9 gene.
Assuntos
Feminino , Humanos , Anemia Ferropriva , DNA , Seguimentos , gama-Globulinas , Corpos de Inclusão , Ferro , Leucócitos , Contagem de Plaquetas , Testes de Função Plaquetária , Púrpura Trombocitopênica Idiopática , TrombocitopeniaRESUMO
May-Hegglin anomaly (MHA) is a myosin-heavy-chain-9 (MYH9)-related disorder characterized by thrombocytopenia with giant platelets and inclusion bodies in leukocytes. MHA does not require treatment, but it may be misdiagnosed as immune thrombocytopenic purpura (ITP) and inappropriately managed. Reported herein is a case of a 12 year old female patient diagnosed as MHA with laboratory findings of severe thrombocytopenia and giant platelets in peripheral blood morphology, and followed up until 23 years of age. The patient had been diagnosed with ITP and treated with intravenous gamma-globulin therapy at another hospital, and showed no improvements in platelet count. She was then referred to our hospital for further diagnostic workup and followed up for 11 years, showing platelet count of 6,000-20,000/µL and prolonged platelet function test. She was occasionally treated with iron therapy due to iron-deficiency anemia. In 2014, we conducted a DNA analysis that revealed c.4339G>T(p.Asp1447Tyr), a known mutation of MYH9 gene.