Investigating the effects of copy number variants on reading and language performance

Table 1 Phenotypic traits available and measures used for PC1 score derivation (labeled with relative loadings on PC1)

Trait	Description (ability assessed)	CLDRC-RD (564)	CLDRC-ADHD (163)
WRead	Reading real words	0.918	0.871
WSpell	Spelling real words	0.813	0.764
PD	Ability to convert letter strings into sounds, according to given phonetic rules	0.895, 0.861^a	0.821, 0.729^a
PA	Ability to recognize and manipulate speech sounds (phonemes)	0.801	0.744
OC	Ability to recognize a word as an orthographic unit and to retrieve the corresponding phonological form	0.764	0.644
NWR	Ability to repeat nonsense words orally presented	0.493	0.355
VIQ	Verbal reasoning
PIQ	Logical reasoning
PC1	Shared variance in reading and language skills	544 (528)	159 (155)
IQ-adjusted PC1	Shared variance in reading and language skills, not shared with performance IQ	544 (525)	159 (155)

Sample sizes of the datasets that underwent the PCA are reported in the header row. The number of samples for which PC1 score was computed are reported at the bottom of the table (as we excluded participants with at least one missing measure among the traits involved in the PCA). These numbers still include LRR outliers and samples discarded in CNV calling and QC process, which were filtered out for the specific purpose of this study, after extraction of PC1 scores. Final sample sizes at the end of all QCs are reported in brackets.
WRead word reading, WSpell word spelling, PD phonological decoding, PA phoneme awareness, OC orthographic coding, NWR nonword repetition, VIQ/PIQ verbal/performance IQ
^aLoadings of nonword reading and phonological choice (respectively) on PC1s

ISSN: 1866-1955