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Heritability of neurocognitive traits in familial schizophrenia
Author(s) -
Husted Janice A.,
Lim Sooyeol,
Chow Eva W.C.,
Greenwood Celia,
Bassett Anne S.
Publication year - 2009
Publication title -
american journal of medical genetics part b: neuropsychiatric genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.393
H-Index - 126
eISSN - 1552-485X
pISSN - 1552-4841
DOI - 10.1002/ajmg.b.30907
Subject(s) - neurocognitive , heritability , endophenotype , schizophrenia (object oriented programming) , psychology , working memory , verbal memory , bivariate analysis , visual memory , audiology , developmental psychology , cognitive psychology , cognition , medicine , psychiatry , genetics , biology , statistics , mathematics
Neurocognitive deficits are considered promising endophenotypes for gene discovery in schizophrenia. Understanding the heritability and genetic inter‐relationships of neurocognitive traits could support their use as alternatives to diagnosis. Participants were 85 adults from 17 multiplex Canadian families with familial schizophrenia linked to 1q23 who had neurocognitive testing results available. Heritability of 13 standard measures assessing motor skills, processing speed, verbal, and visuospatial memory, attention/working memory, executive functioning, and IQ was estimated using variance component models and SOLAR software. We then investigated bivariate relationships between those variables found to be heritable. IQ showed the highest heritability (h 2 = 0.64–0.74) and seven other neurocognitive measures, reflecting immediate and delayed verbal memory, attention/working memory, delayed visual memory, processing speed and motor skills, showed significant heritability (h 2 = 0.31–0.62) under one or more of the models assessed. A schizophrenia diagnostic covariate was significant ( P < 0.0001) for all heritable variables. Bivariate analyses suggested that memory‐IQ and visuomotor‐processing speed formed two groups of heritable traits. The results provide further evidence of the heritability of selected neurocognitive measures, and their relationship to schizophrenia and underlying genetic architecture. Composite measures of memory or processing speed may be heritable phenotypes useful for studies of neurocognition. © 2009 Wiley‐Liss, Inc.