RT Journal A1 HOLLENHORST RW T1 Heredo-retinopathia congenitalis monohybrida recessiva autosomalis: A genetical-statistical study JF A.M.A. Journal of Diseases of Children JO A.M.A. Journal of Diseases of Children YR 1959 FD February 1 VO 97 IS 2 SP 251 OP 251 DO 10.1001/archpedi.1959.02070010253022 UL http://dx.doi.org/10.1001/archpedi.1959.02070010253022 AB This is a monumental study of 175 cases of a hereditary form of congenital blindness or severe impairment of vision, with 303 unaffected siblings in the 105 families concerned. A brief account is given of an extensive genealogic investigation in which more than eight thousand ancestors were traced. It was found that twenty-nine of the one hundred five families belong to five large family complexes.The mode of inheritance of the disease was found to be monohybrid, recessive autosomal, with complete penetrance. The disease is responsible for about ten per cent of the cases of blindness in children who reach school age in Sweden, with a frequency in the general population of about three in one hundred thousand and a heterozygote frequency of between one-half and one per cent.Vision is defective at birth, with either total blindness or greatly impaired sight with loss of central vision. There is general