title: Visual pathway deficit in female fragile X premutation carriers: a potential endophenotype.
abstract: Previous studies indicated impaired magnocellular (M) and relatively spared parvocellular (P) visual pathway functioning in patients with fragile X syndrome. In this study, we assessed M and P pathways in 22 female fragile X premutation carriers with normal intelligence and in 20 healthy non-carrier controls. Testing procedure included visual contrast sensitivity and vernier threshold measurements. Results revealed that carriers were selectively impaired on tests of M pathways (low spatial/high temporal frequency contrast sensitivity and frequency-doubling vernier), whereas they showed intact performance on P pathway tests. These results suggest that the deficit of the M pathway is an endophenotype of fragile X syndrome.
authors.affiliation: Semmelweis University, Department of Psychiatry and Psychotherapy, H1083 Budapest, Hungary. szkeri@phys.szote.u-szeged.hu
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Kéri
authors.forename: György
authors.initials: G
authors.lastname: Benedek
mesh_terms: D000704:Analysis of Variance; D016002:Discriminant Analysis; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005600:Fragile X Syndrome / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D010641:Phenotype; D010775:Photic Stimulation; D012684:Sensory Thresholds / Q000502:physiology; D014795:Visual Pathways / Q000503:physiopathology*; D014796:Visual Perception / Q000235:genetics*; D055815:Young Adult
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human