[Familial erythrocytosis type 2 due to VHL germline mutations: a case report and literature review].

To enhance the understanding of familial erythrocytosis type 2 (ECYT2) resulting from compound heterozygous mutations in the VHL gene. Methods: We conducted a retrospective analysis of the case data from a patient with ECYT2 to investigate its pathogenesis, clinical features, diagnosis and treatment options, as well as prognosis, while also reviewing the relevant literature. Results: A 31-year-old man was admitted to the hospital due to facial and hand flushing that had persisted for 29 years. Whole exome sequencing revealed compound heterozygous mutations in VHL p.P81L and p.N90T. Both of his parents were found to carry only one of these heterozygous mutations, yet they exhibited normal phenotypes. Based on the patient's hematological tests, a clear diagnosis of ECYT2 was established. Following treatment with erythrocytapheresis and daily administration of aspirin at a dosage of 100 mg, the patient experienced relief from dizziness and headaches associated with blood hyperviscosity, without any thrombotic or bleeding complications during this period. Conclusions: ECYT2 is a rare group of autosomal recessive genetic disorders. This case of ECYT2, resulting from compound heterozygous mutations in the VHL gene, represents the first report in China. Clinically, it is characterized by elevated red cell mass, normal or increased serum erythropoietin levels, and normal hemoglobin oxygen affinity levels. These factors contribute to thrombotic and bleeding complications that can lead to early mortality.