M-CONES AND L-CONES IN EARLY INFANCY - III - COMPARISON OF GENOTYPIC AND PHENOTYPIC MARKERS OF COLOR-VISION IN INFANTS AND ADULTS

Genetic analyses were performed on five male children (similar to 3 ye ars), two suspect color-normals and three suspects for congenital colo r vision deficiencies. These classifications were based on visually-ev oked potential (VEP) responses to M- and L-cone-isolating stimuli obta ined in a previous study when each subject was either 4- or 8-weeks ol d. The present analyses were performed in a blind study to characteriz e the genotypes of these subjects. Four male adults with various color vision phenotypes were also tested as a control. DNA was isolated usi ng a non-invasive technique followed by polymerase chain reaction (PCR ) amplification and restriction enzyme analysis to examine the genomic DNA of each subject the genetic analyses confirmed the VEP identifica tion of two color defective infants, and were consistent with the diag nosis of two other infants as color normal. A third infant was predict ed by VEP analysis to have a protan defect, but he did not have a gene array typically found in protan observers. (C) 1998 Elsevier Science Ltd. All rights reserved.