May-Hegglin Anomaly

May-Hegglin anomaly is a rare blood disorder characterized by an increase in platelet size and a decrease in platelet count. This condition can lead to difficulties in the blood clotting process.

Symptoms

May-Hegglin anomaly is characterized by a decreased platelet count and increased platelet size. In addition, this condition may result in prolonged bleeding time, hematomas and persistent thrombocytopenia. The presence of blue cytoplasmic inclusions in neutrophils is also observed.

Disease Management

Most dogs with this disease do not experience severe symptoms or complications, so no specific treatment is required. In cases where the dog has significant bleeding or extremely low platelet levels, platelet transfusions may be considered as a treatment option.

Genetic basis

This disease follows an autosomal dominant mode of inheritance. Autosomal dominant inheritance means that dogs only have to inherit one copy of the mutation or pathogenic variant to be at risk of developing the disease. Each puppy born to a parent carrying one copy of the mutation has a 50% chance of inheriting one copy of the mutation and being at risk for the disease. Breeding between dogs carrying genetic variants that can cause disease is not recommended, even if they do not show symptoms.

Technical report

May-Hegglin anomaly is a blood disorder belonging to the group of thrombocytopenias, characterized by a low platelet count. Currently, the anomaly has only been described in the Pug breed. A study by Flatland et al. (2011) identified a mutation (c.5521G>A) in the MYH9 gene, which results in the substitution of lysine for glutamine at position 1841 of the resulting protein. This mutation has been associated as a possible causative variant of May-Hegglin anomaly, and is identical to a mutation found in humans affected by this anomaly.

Most affected breeds

Bibliography

Flatland B, Fry MM, Baek SJ,et al. May-Hegglin anomaly in a dog. Vet Clin Pathol. 2011 Jun;40(2):207-14.