Achille Emperaire, an artist and a friend of Paul Cezanne, was born in Aix-en-Provence in 1829, ten years after Cezanne. Little is known about his life. In his early career, he moved frequently between Paris and Aix, working under the influence of the painter Thomas Couture and subsisting on only fifteen francs a month, often by copying pictures in the Louvre.1 His artistic output was not prolific, but his paintings, particularly his nudes, show a fullness of form, an abundance of curves, and romantic inspiration similar to the works of Delacroix and Seurat. He repeatedly and unsuccessfully tried to exhibit his work at the Salon, the official art exhibition of the Academie des Beaux-Arts in Paris.2 Cezanne had an on-off relationship with Emperaire, at times helping him to gain employment, for example as a financial administrator for the Societe des Artistes Francais in Paris, but he frequently, and cruelly, did not support Emperaire through long periods of financial hardship. However, Cezanne did appreciate his friend's work, and ten years before Emperaire's death in Aix in 1898 he wrote of him in a letter to Gasquet as follows: ‘If I had been given the chance to “realiser”, it is I who should have remained in my corner with some of the studio colleagues with whom we used to go to drink a stein of beer. I still have a good friend from those days; ah well, he didn't succeed, but just the same he was devilishly more painter than the bemedalled and decorated tramps that make one sweat.’1 Emperaire's name has been saved from oblivion only by the portraits Cezanne made of him. The most notable is the full-length portrait, more than six feet high, that hangs in the Musee d'Orsay in Paris (Figure 1). Cezanne submitted this work to the Salon jury in 1870, fully expecting the provocative likeness of his friend to be rejected, which it promptly was. In the painting, the ‘dwarf-artist’ is seated in a large upholstered armchair with a flowered slipcover, his crippled body wrapped in a blue flannel robe, his outsized pensive face with fashionable moustache and goatee, and his spindly legs resting on a footstool. Above the chair, against the uniformly dark background of the canvas, a painted inscription in Bodoni-type lettering reads: ‘Achille Emperaire Peintre’. The disproportionate nature of his dwarfism is apparent, along with a large forehead and a thick-set short trunk with long and thin extremities. But what was the cause of his dwarfism? Figure 1 Portrait du peintre Achille Emperaire (1867-1868); oil on canvas, 200×122 cm; Musee d'Orsay, Paris. [In colour online]. The differential diagnosis for short-trunk disproportionate dwarfism includes metatropic dysplasia, Kniest dysplasia, Morquio syndrome and spondyloepiphyseal dysplasia. All of these conditions are associated with normal intelligence. Metatropic dysplasia is extremely rare, only 80 cases having been reported. The face tends to be of normal appearance and there is severe kyphoscoliosis, progressive large joint contractures, and limbs shaped like dumb-bells due to metaphyseal flaring—characteristic features not seen in this portrait or in photographs of Emperaire. Kniest dysplasia resembles metatropic dysplasia, with similar trunk and limb changes, and can again be ruled out. Morquio syndrome (type IV mucopolysaccharidosis) can be difficult to distinguish from spondyloepiphyseal dysplasia. In Morquio syndrome, however, the hands are characteristically short and broad due to expansion of the metacarpals, which also have pointed proximal ends, and small irregular carpal bones. In addition, the facial features tend to be coarse but otherwise unremarkable. Emperaire is unlikely to have had Morquio syndrome, as his hands seem to be of relatively normal shape and size. Emperaire has the characteristic flat face with wide set eyes typical of spondyloepiphyseal dysplasia, in particular the congenita form. The face is normal in the milder tarda form and it is not associated with severe short stature. Spondyloepiphyseal dysplasia congenita is suggested here by his short neck, pectus carinatum (evident in photographs), and the hands and feet of normal size relative to the lengths of the limbs (rhizomelic and mesomelic shortening). Inheritance is by autosomal dominant transmission, but most cases are sporadic in nature and are caused by mutations in the COL2A1 locus on chromosome 12.4 Indeed, there are no records of dwarfism in the members of Achille Emperaire's family.