Double nucleotidic mutation of the MYH9 gene in a young patient with end-stage renal disease.

Alport’s syndrome, a renal disorder with inherited transmission, is characterized by ultrastructural changes of glomerular basement membrane and basement membranes elsewhere. A progressive haematuric nephritis, sensorineural hearing loss and familial occurrence in successive generations are typical of this disorder. X-linked dominant inheritance is quite frequent (85–90% of the families) [1]. Alport-like syndromes identify a group of diseases characterized by thrombocytopaenia with ‘giant platelets’ and autosomal dominant transmission. Their distinguishing features consist of the presence of nephritis, cataracts, hearing loss or deafness with or without leucocytic intracytoplasmatic inclusions (named ‘Dhole bodies’). This group of diseases includes: the May–Hegglin anomaly, Fechtner syndrome, Sebastian syndrome and Epstein syndrome. Unlike in Alport’s syndrome, the genetic mutations linked to this group of disorders are in the human non-muscle myosin IIA heavy chain gene (MYH9) [2]. The May–Hegglin anomaly is a rare autosomal dominant disorder characterized by abnormally large platelets, leucocytic inclusions and thrombocytopaenia, which predisposes patients to bleeding disorders [3]. The Sebastian and Fechtner syndromes share these features, but patients with the Fechtner syndrome also show high-tone sensorineural deafness, cataracts and nephritis [4], while the May–Hegglin anomaly and Sebastian syndrome are differentiated by an ultrastructural examination of leucocyte inclusions. The Epstein syndrome consists of deafness and nephritis in the absence of cataracts and leucocytic inclusions [2]. The clinical features of all of these genetic disorders are shown in Table 1.