Table 2.

Nucleotide homologies of DNA and RNA amplified from individuals with schizophrenia (SCZ) and unaffected controls

	Patient group	New-onset SCZ (A4)		New-onset SCZ (A5)		Chronic SCZ (n = 4)	Unaffected (n = 6)
	Template	DNA	RNA	DNA	RNA	DNA	DNA
	No. clones analyzed	16	7	8	9	30	53
Retrivirus homology
HERV-W		4 (25%)	7 (100%)*	1 (12.5%)	9 (100%)†	10 (33.3%)	14 (26.4%)
FRD		3 (19.0%)	0	1 (12.5%)	0	10 (33.3%)	14 (26.4%)
ERV9		4 (25.0%)	0	2 (25.0%)	0	5 (16.7%)	13 (24.5%)
HC2		3 (19.0%)	0	1 (12.5%)	0	5 (16.7%)	4 (7.5%)
MLN		1 (6.0%)	0	0	0	0	5 (9.5%)
HERV-K		0	0	1 (12.5%)	0	0	2 (3.8%)
Other		1 (6.0%)	0	2 (25.0%)‡	0	0	1 (1.9%)

DNA was isolated from peripheral blood mononuclear cells from individuals A4 and A5 with newly diagnosed schizophrenia as well as from four individuals with chronic schizophrenia and six unaffected individuals. DNA was extracted and amplified by PCR without prior reverse transcription. RNA was extracted from the cell-free CSFs of patients A4 and A5, reverse transcribed, and amplified by PCR, as described above. Homologies shown represent those with ≥90% nucleotide identity. Data presented relating to new-onset schizophrenia denote the homologies of clones derived from the indicated individuals. Data for the chronic schizophrenia and unaffected groups represent the homologies of clones derived from four and six individuals, respectively. 

^*P = 0.0013 compared to corresponding A4 DNA, Fisher's exact test (two-tailed). 

^† P = 0.0004 compared to corresponding A5 DNA, Fisher's exact test (two-tailed). 

^‡ Represents homology to two different uncharacterized retroviral sequences.