Hereditary macrothrombocytopathia, nephritis and deafness

Two unrelated families were studied in which two members of each have a syndrome of macrothrombocytopathia, nephritis and deafness. A third member of one family, a young child, has the platelet disorder and a mild hearing loss. The mode of inheritance of the syndrome appears to be dominant. Except for its severity in affected females, the renal disease is indistinguishable from the classic type of hereditary nephritis. Likewise, the high frequency sensorineural hearing loss is similar to that seen in Alport's syndrome. The platelet disorder is characterized by thrombocytopenia, giant platelets with an abnormal ultrastructure, prolonged bleeding time and defective adherence of platelets to glass. Aggregation in response to collagen and epinephrine, and release of platelet factor 3 are impaired, and the release of nucleotide after exposure to collagen is abnormally low.