The Genetics of Retinoblastoma.

(1) Sporadic cases.-Retinoblastoma is a rare tumour and hereditary manifestations of it are rarer still. At the Royal Eye Hospital, London, there were seen 59 children with retinoblastoma during the 50 years 1894-1943, and among these there was only one familial group, now observed over three generations. This group has supplied 6 instances of the affection, the remaining 53 being isolated sporadic cases. Amongst these 53 isolated cases there were eight bilateral cases (151 per cent.). The subjoined t4ble gives the salient features as to sex and age distribution of the sporadic cases.