Through osmosis (water movement from a low solute concentration to an area of high solute concentration) water is reabsorbed back into the blood from nephron tubules in the kidney. This maintenance of water concentration in the blood is essential for maintaining blood pressure and is affected in nephritis. Diagnosis
The cardinal symptom in Epstein syndrome is thrombocytopaenia with giant platelets (macrothrombocytopenia). A peripheral blood smear is taken from the patient and a light microscope is used to these identify giant platelets. Leukocyte inclusions are also examined for, because approximately 41.1% of R207 mutations have leukocyte inclusions. These are often abnormal neutrophils with a small size of approximately less than 0.7 um and have an abnormallocation on the non-muscle myosin heavy chain IIA (NMMHC-II). These inclusion bodies have RNA and no DNA. RNA in these inclusion bodies can be located in immunofluorescence analysis with the anti nonmuscle heavy chain IIA antibody.Hematology analysers or a hemocytometer can be used to determine the amount of platelets. A sample of blood is drawn from a patients arm. A small amount of platelets in blood smears compared to the normal range of 150,000 to 450,000 platelets in microliter of blood suggest thrombocytopaenia, which is a common symptom in Epstein syndrome.A urine sample is often collected where a urinalysis can be used to determine the volume of proteins excreted in urine. Abnormal amounts of protein detected means the patient has proteinuria. Patients with Epstein syndrome often have large proteinuria where they excrete above 3.5g of protein in their urine in a day.
Epstein syndrome is a rare genetic disease characterized by a mutation in the MYH9 gene in nonmuscle myosin. This disease affects the patients renal system and can result in kidney failure. Epstein Syndrome was first discovered in 1972 when two families had similar symptoms to Alport syndrome. Epstein syndrome and other Alport-like disorders were seen to be caused by mutations in the MYH9 (myosin heavy chain 9)  gene, however, Epstein syndrome differs as it was more specifically linked to a mutation on the R702 codon on the MYH9 gene. Diseases with mutations on the MYH9 gene also include May–Hegglin anomaly, Sebastian syndrome and Fechtner syndrome. Signs and symptoms
Initial symptoms are often described as bleeding tendency and thrombocytopenia. Bleeding tendency may be observed in epistaxis and purpura. Other symptoms may include macrothrombocytopenia, proteinuria, nephropathy, sensorineural hearing loss, low platelet count, oral lesions and cataracts. The most common symptoms include macrothrombocytopenia, mild sensorineural hearing loss and nephritis. The symptoms and the severity of these symptoms vary between patients where most patients experience nephritis in childhood and then progress to kidney failure in adolescence. In macrothrombocytopenia platelet sizes can reach to approximately 6.6 um compared to a normal platelet size of 2.5 um where 30% platelets can reach the size of an erythrocytes. This large platelet size can be compared with MYH9 disorders where platelet size can vary between 4.5 um and the 6.6 um that is found in Epstein Syndrome with mutations on the R207 codon. Causes
Epstein Syndrome is caused by a mutation in MYH9 gene.