rs3043732 is no longer in dbSNP. Take a look HERE.
To look up rs IDs in biomaRt, you need to do this:
require(biomaRt)
ensembl <- useMart("ENSEMBL_MART_SNP", dataset = "hsapiens_snp")
getBM(attributes=c(
"refsnp_id", "chr_name", "chrom_start", "chrom_end",
"allele", "mapweight", "validated", "allele_1", "minor_allele",
"minor_allele_freq", "minor_allele_count", "clinical_significance",
"synonym_name", "ensembl_gene_stable_id"),
filters="snp_filter", values="rs6025",
mart=ensembl, uniqueRows=TRUE)
refsnp_id chr_name chrom_start chrom_end allele mapweight
1 rs6025 1 169549811 169549811 C/T 1
validated
1 1000Genomes,Cited,ESP,ExAC,Frequency,gnomAD,HapMap,Phenotype_or_Disease,TOPMed
allele_1 minor_allele minor_allele_freq minor_allele_count
1 C TRUE 0.00599042 30
clinical_significance synonym_name
1 benign,pathogenic,drug response,risk factor 17284
ensembl_gene_stable_id
1 ENSG00000198734
Look up all available attributes with listAttributes(ensembl)
Kevin