RESUMO
Gray platelet syndrome (GPS) is an inherited bleeding disorder characterized by thrombocytopenia and the absence of α-granules in platelets. Patients with GPS present with mild to moderate bleeding and many develop myelofibrosis. The genetic cause of GPS is unknown. We present 2 Native American families with a total of 5 affected persons and a single affected patient of Pakistani origin in which GPS appears to be inherited in an autosomal recessive manner. Homozygosity mapping using the Affymetrix 6.0 chips demonstrates that all 6 GPS-affected persons studied are homozygous for a 1.7-Mb region in 3p21. Linkage analysis confirmed the region with a logarithm of the odds score of 2.7. Data from our families enabled us to significantly decrease the size of the critical region for GPS from the previously reported 9.4-Mb region at 3p21.
Assuntos
Mapeamento Cromossômico/métodos , Cromossomos Humanos Par 3 , Loci Gênicos , Síndrome da Plaqueta Cinza/genética , Análise em Microsséries/métodos , Polimorfismo de Nucleotídeo Único , Estudos de Casos e Controles , Cromossomos Humanos Par 3/genética , Análise por Conglomerados , Família , Feminino , Genes Recessivos/genética , Ligação Genética/fisiologia , Homozigoto , Humanos , Masculino , LinhagemRESUMO
Next-generation RNA sequence analysis of platelets from an individual with autosomal recessive gray platelet syndrome (GPS, MIM139090) detected abnormal transcript reads, including intron retention, mapping to NBEAL2 (encoding neurobeachin-like 2). Genomic DNA sequencing confirmed mutations in NBEAL2 as the genetic cause of GPS. NBEAL2 encodes a protein containing a BEACH domain that is predicted to be involved in vesicular trafficking and may be critical for the development of platelet α-granules.