Contents

For HGNChelper paper, we used the results from inst/analyses/test_GPLs.R script done on September 28th, 2020. The output is saved as inst/analyses/gpls_already_tested.csv.

Briefly, we downloaded 20,716 GEO platforms where 5,128 were from Homo Sapiens. If more than 50% of values of a column is human gene symbol, we consider that column as a ‘(unique) gene symbol’ column and summarized the performance of HGNChelper on the values of that column in the gpls_already_tested.csv table. The two main information in that table are the fraction of valid gene symbols before/after HGNChelper.

dat_dir <- "~/data/HGNChelper_raw_data_ver1"
x <- read.csv("gpls_already_tested_ver1.csv", as.is = TRUE)
x$valid.after.hgnchelper.frac <- as.numeric(x$valid.after.hgnchelper.frac)
x <- x[!is.na(x$valid.frac),]
x <- x[x$valid.frac > 0,]

outlier table contains the summary of platforms that have less than 90% validated gene symbol after HGNChelper.

outlier <- x[x$valid.after.hgnchelper.frac < 0.9,]
outlier <- outlier[order(outlier$valid.after.hgnchelper.frac),]
head(outlier)
##      platform     colname frac.hgnc  nrow valid.frac
## 85   GPL26963         ORF 0.5044283 60795  0.4926269
## 37   GPL25978          ID 0.5111388 43317  0.4765565
## 168  GPL24444          ID 0.5111855 43315  0.4765786
## 237  GPL25261     Gene ID 0.5295989 43315  0.4937454
## 1640 GPL16309 Gene Symbol 0.5147768 62976  0.4957780
## 288  GPL23465          ID 0.5168011 36337  0.4976745
##      valid.after.hgnchelper.frac      distribution submission_date
## 85                     0.5025098 custom-commercial     Jul 25 2019
## 37                     0.5044902 custom-commercial     Dec 22 2018
## 168                    0.5051137        commercial     Dec 27 2017
## 237                    0.5233084        commercial     Jul 02 2018
## 1640                   0.5531582 custom-commercial     Nov 20 2012
## 288                    0.5560173 custom-commercial     May 11 2017

Column name of GPL that wasn’t efficiently corrected by HGNChelper.

table(outlier$colname) %>% sort(., decreasing = TRUE)
## 
##                                         ORF 
##                                          85 
##                                 GENE_SYMBOL 
##                                          56 
##                                     SPOT_ID 
##                                          28 
##                                      Symbol 
##                                          21 
##                                 Gene Symbol 
##                                          19 
##                                 Gene_Symbol 
##                                          13 
##                                  GeneSymbol 
##                                          13 
##                                 gene_symbol 
##                                          12 
##                                    GeneName 
##                                          10 
##                                          ID 
##                                          10 
##                           Blast Gene Symbol 
##                                           7 
##                                 GENE SYMBOL 
##                                           7 
##                                        name 
##                                           7 
##                                      symbol 
##                                           7 
## CompositeSequence BioSequence [Gene Symbol] 
##                                           6 
##                                    ORF_LIST 
##                                           6 
##                                      SYMBOL 
##                                           6 
##                                        Name 
##                                           5 
##                                 Gene_symbol 
##                                           4 
##                         OligoSet_geneSymbol 
##                                           3 
##                                 gene symbol 
##                                           2 
##                                    GENENAME 
##                                           2 
##                                    HUGOname 
##                                           2 
##                          Primary Annotation 
##                                           2 
##                       Primary Sequence Name 
##                                           2 
##                       Alternative gene name 
##                                           1 
##                       Closest_TSS_gene_name 
##                                           1 
##                                      Common 
##                                           1 
##                                      COMMON 
##                                           1 
##                         Ensembl_gene_symbol 
##                                           1 
##                               External name 
##                                           1 
##                                        GENE 
##                                           1 
##                                     Gene ID 
##                                           1 
##                                   gene name 
##                                           1 
##                                   Gene name 
##                                           1 
##                                   Gene Name 
##                                           1 
##                                 Gene symbol 
##                                           1 
##                                Gene Symbols 
##                                           1 
##                                 GENE_SYBMOL 
##                                           1 
##                                    GENE_SYM 
##                                           1 
##                                gene_symbols 
##                                           1 
##                                 Gene.Symbol 
##                                           1 
##                                     GeneSym 
##                                           1 
##                                  GENESYMBOL 
##                                           1 
##                                 GeneSymbols 
##                                           1 
##                          Human Gene Symbols 
##                                           1 
##                               Reporter_Name 
##                                           1 
##                                     SeqName 
##                                           1 
##                                  Symbol v12 
##                                           1 
##                     symbol_from_entrez_gene 
##                                           1 
##                          V3.0.3_gene_symbol 
##                                           1

1 Reasons for outliers

1.1 Uncharacterized genes

HGNChelper was applied on ORF column of GPL26963 and only ~50% of gene symbols were valid both before and after applying HGCNhelper.

outlier[1,]
##    platform colname frac.hgnc  nrow valid.frac valid.after.hgnchelper.frac
## 85 GPL26963     ORF 0.5044283 60795  0.4926269                   0.5025098
##         distribution submission_date
## 85 custom-commercial     Jul 25 2019

This is the actual information of GPL26963 fetched from GEO.

i <- 1   # GPL26963
gpl <- outlier[i, "platform"]
gpldat <- getGEO(filename = file.path(dat_dir, "platforms", paste0(gpl, ".soft")))
gpltable <- Table(gpldat)
head(gpltable)
##                ID TRANSCRIPT_TYPE       ACC       ORF SOURCE BUILD CHROM STRAND
## 1 ASHGV40000072V5          lncRNA NR_027417 LOC644669 Refseq  HG19 chr18      -
## 2 ASHGV40000162V5          lncRNA NR_037149 NME1-NME2 Refseq  HG19 chr17      +
## 3 ASHGV40000243V5          lncRNA NR_130700 LOC728323 Refseq  HG19  chr2      +
## 4 ASHGV40004835V5          lncRNA NR_130699 LOC728323 Refseq  HG19  chr2      +
## 5 ASHGV40030421V5          lncRNA NR_130701 LOC728323 Refseq  HG19  chr2      +
## 6 ASHGV40000318V5          lncRNA NR_046258    FAR2P2 Refseq  HG19  chr2      -
##     txStart     txEnd GENE DESCRIPTION
## 1  15313554  15325918                 
## 2  49230896  49249105                 
## 3 243030783 243102476                 
## 4 243030783 243102476                 
## 5 243030783 243102476                 
## 6 131174325 131186119                 
##                                                       SEQUENCE SPOT_ID
## 1 ATAGTAATCCAGAAGGAACATCTGAAGGAACACTTGATGAGGCTGCACCCTTGGCAGAAA      NA
## 2 TTCTGCATACAAGTTGGCAGGACCATGGCCAACCTGGAGCGCACCTTCATCGCCATCAAG      NA
## 3 CTGAGCACTGATACAAAGAAAGACAAACATCACCAAACCAATGCAGACCAAACCAATGCA      NA
## 4 CAGCTGAGCACTGATACAAAGAAAGACAAACATCATATCTCTCTTGATTCTTAGTAACAA      NA
## 5 TTAAATAGCGAAGATGGAGAAATACTCAATAATGAAGAGCATGAATATGCATCCAAAAAA      NA
## 6 AGCAAAATGTGATTCCAGGTCTTGGCAACCTCTGAAATTCCAACTCCATTTGCGAGAGCT      NA
  • Uncharacterized gene ([from NCBI] Symbols beginning with LOC. When a published symbol is not available, and orthologs have not yet been determined, Gene will provide a symbol that is constructed as ‘LOC’ + the GeneID. )
columnName <- outlier[i, "colname"]
checkGeneSymbols(head(gpltable[,columnName]))
##           x Approved Suggested.Symbol
## 1 LOC644669    FALSE             <NA>
## 2 NME1-NME2     TRUE        NME1-NME2
## 3 LOC728323    FALSE             <NA>
## 4 LOC728323    FALSE             <NA>
## 5 LOC728323    FALSE             <NA>
## 6    FAR2P2     TRUE           FAR2P2

1.2 Probe ID

1.2.1 Case_1

ID column contains both gene symbol and probe name.

i <- 2   # GPL25978
gpl <- outlier[i, "platform"]
gpldat <- getGEO(filename = file.path(dat_dir, "platforms", paste0(gpl, ".soft")))
gpltable <- Table(gpldat)
head(gpltable)
##        ID                                              ProbeName GB_ACC
## 1     CNP                A_21_P0014015;A_23_P21838;A_33_P3250383       
## 2   HMGCL                                A_33_P3388283;A_23_P145       
## 3   HTR2C                             A_23_P433586;A_33_P3319176       
## 4    MTRR A_21_P0014139;A_21_P0014138;A_33_P3304377;A_23_P252211       
## 5  PHYKPL                              A_33_P3253628;A_23_P41888       
## 6 AKAP17A                               A_24_P16856;A_23_P342668       
##     Genbank ACCID
## 1 ENST00000592861
## 2 ENST00000496907
## 3 ENST00000276198
## 4 ENST00000507837
## 5 ENST00000476487
## 6 ENST00000381261
##                                                                                                                  Description
## 1                      ens|2',3'-cyclic nucleotide 3' phosphodiesterase [Source:HGNC Symbol;Acc:HGNC:2158] [ENST00000592861]
## 2                        ens|3-hydroxymethyl-3-methylglutaryl-CoA lyase [Source:HGNC Symbol;Acc:HGNC:5005] [ENST00000496907]
## 3    ens|5-hydroxytryptamine (serotonin) receptor 2C, G protein-coupled [Source:HGNC Symbol;Acc:HGNC:5295] [ENST00000276198]
## 4 ens|5-methyltetrahydrofolate-homocysteine methyltransferase reductase [Source:HGNC Symbol;Acc:HGNC:7473] [ENST00000507837]
## 5                          ens|5-phosphohydroxy-L-lysine phospho-lyase [Source:HGNC Symbol;Acc:HGNC:28249] [ENST00000476487]
## 6                               ens|A kinase (PRKA) anchor protein 17A [Source:HGNC Symbol;Acc:HGNC:18783] [ENST00000381261]
##                                                                                                                                                                                                                                              SEQUENCE
## 1                                                              GTCTGGAAATCAAAATCACAGATACTCCACTCCTCTTTGTGTCTTCCAGCCCCATAATGT;TAACAGGGCCTTGCTAATCGGGTTGTCACTCAACAAAAGTGCTTTGGATTTAAGTTACTA;CCCTATAATGCTGGAGCGGCTACTAAAAAGGATAAAATGTATCACTTAAATGTTACCAAA
## 2                                                                                                                           AAGAGTGACTTCCTCTCCTATGCCTTGCCAGGCAGGTAAAGGGGAATTCTGCACAGCTGA;GGACATGGAAATGAGAATAGGTTAAATGGTGCAGGTACCTCATAGCCAGCTCTACACAGA
## 3                                                                                                                           AATGGCTGAAGAAACACAGCATGCATTTAGCATGAGTTCTGCACATACAGATGGTGTCCT;GAAACTTTGGAAGTTTTACTTGATTAAGGACTACAGAATTGGGCCCTTAGAATGTGAAAA
## 4 GATCCTTCAATCCAGACTGTGAAGAAAACCCTTGAGTTAAGACATTAGACATCTGTGCAA;GTGGATGGCAATACAAATCCTTCTTCATCTAATTTAATTTCAACATCTGGTGAGAGAAGA;CCTCTCTGAATATTCCTGGTTTACCCCCAGAATATTTACAGGTACATCTGCAGGAGTCTC;TTCCATGCAAAGGCTTCCTGAAATAGGGGAGACTGACTGAGTAGCTCATTCTTGTGACTT
## 5                                                                                                                           CAAAAGGTACCAAAAAGTACAGTAAAATTAACACTTCCGTTACAGGAAATGTATGACGCA;CCTGCTCTGCCTAAGTGTACTCCAGAAGAAACTCATCTCATCCAAATACACGCTATTGAG
## 6                                                                                                                           TCTGATTACAGTTGTGATAAGTCCCCGGGAAGGAGCATGACAAGAGGCTGAGACATGTGG;AAATAGCTGTAACGTTCGCGTTAGGAAAGATGGTGTTTATTCCAGTTTGCATTTTTATGG
##           SPOT_ID
## 1 ENST00000592861
## 2 ENST00000496907
## 3 ENST00000276198
## 4 ENST00000507837
## 5 ENST00000476487
## 6 ENST00000381261
columnName <- outlier[i, "colname"]
columnName
## [1] "ID"
checkGeneSymbols(tail(gpltable[,columnName]))
##            x Approved Suggested.Symbol
## 1 THC2767512    FALSE               NA
## 2 THC2772172    FALSE               NA
## 3 THC2773168    FALSE               NA
## 4 THC2773489    FALSE               NA
## 5 THC2774795    FALSE               NA
## 6 THC2779931    FALSE               NA

1.2.2 Case_2

ID column contains both gene symbol and experiment-specific, re-annotated ID.

i <- 3   # GPL24444
gpl <- outlier[i, "platform"]
gpldat <- getGEO(filename = file.path(dat_dir, "platforms", paste0(gpl, ".soft")))
gpltable <- Table(gpldat)
head(gpltable)
##       ID                                ProbeName                    Genbank ID
## 1 MARCH1 A_24_P188800;A_33_P3293362;A_33_P3247205 NM_017923;NM_022746;NM_022746
## 2 MARCH2   A_23_P33683;A_23_P200685;A_33_P3219434 NM_016496;NM_017898;NM_017898
## 3 MARCH3                A_24_P555473;A_23_P321511           NM_178450;NM_178450
## 4 MARCH4                             A_23_P333228                     NM_020814
## 5 MARCH5                              A_24_P64393                     NM_017824
## 6 MARCH6                             A_23_P110492                     NM_005885
##                                                                                                                                                                                                                                                                                                                Description
## 1 ref|Homo sapiens membrane-associated ring finger (C3HC4) 1, E3 ubiquitin protein ligase (MARCH1), transcript variant 2, mRNA [NM_017923];ref|Homo sapiens mitochondrial amidoxime reducing component 1 (MARC1), mRNA [NM_022746];ref|Homo sapiens mitochondrial amidoxime reducing component 1 (MARC1), mRNA [NM_022746]
## 2 ref|Homo sapiens membrane-associated ring finger (C3HC4) 2, E3 ubiquitin protein ligase (MARCH2), transcript variant 1, mRNA [NM_016496];ref|Homo sapiens mitochondrial amidoxime reducing component 2 (MARC2), mRNA [NM_017898];ref|Homo sapiens mitochondrial amidoxime reducing component 2 (MARC2), mRNA [NM_017898]
## 3                                                                                    ref|Homo sapiens membrane-associated ring finger (C3HC4) 3, E3 ubiquitin protein ligase (MARCH3), mRNA [NM_178450];ref|Homo sapiens membrane-associated ring finger (C3HC4) 3, E3 ubiquitin protein ligase (MARCH3), mRNA [NM_178450]
## 4                                                                                                                                                                                                       ref|Homo sapiens membrane-associated ring finger (C3HC4) 4, E3 ubiquitin protein ligase (MARCH4), mRNA [NM_020814]
## 5                                                                                                                                                                                                                                    ref|Homo sapiens membrane-associated ring finger (C3HC4) 5 (MARCH5), mRNA [NM_017824]
## 6                                                                                                                                                                                 ref|Homo sapiens membrane-associated ring finger (C3HC4) 6, E3 ubiquitin protein ligase (MARCH6), transcript variant 1, mRNA [NM_005885]
##                                                                                                                                                                                 SEQUENCE
## 1 GTCACGCAAAAGATTTTCAGAAAATGTTCGGATATAATTAGCTCTGTTAAATACCCACAG;AGTTAAAGCAACCAACTTCAGGCCCAATATTGTAATTTCAGGATGCGATGTCTATGCAGA;CTGAAAACCTTTAAAGGGGGAAAAGGAAAGCATATGTCAGTTGTTTAAAACCCAATATCT
## 2 CAGCATTCTCCACTGGCAGCTGGACTCCTGAAGAAGGTGGCAGAGGAGACACCAGTATGA;TAACAACAGCAGCAACGATACATCAGCAAATCCTTATTATCCAGCCTTCAACTATCTTTA;AATGAAAATGGAGAATTTCAGGCCAAATATTGTGGTGACCGGCTGTGATGCTTTTGAGGA
## 3                                                              CTTGCTGTGATTCTGTCCTAATCATTTTTCTTGAGAATGTCATGTAGAGATAAATGTGTG;TCGGACCAATCAGAGGGTGATTCTCCTCATTCCAAAGTCTGTCAATGTACCTTCTAACCA
## 4                                                                                                                           TTTTTAAAACTCTCTGTTGTTTGTAATATTCTCTTAAAAGCTTGAAAATAAAACTTCTTT
## 5                                                                                                                           AGCCCCGAATTGAACACTTTTAAACCTAAAGAGCCTTATTATTATTAGCTCGAGAAATAC
## 6                                                                                                                           TAAAGAGCAATGTGTTCTGGCTGTTTTATACTTCAACAATTTTTTCCCTAAGTGGTAAGC
##                           GB LIST SPOT_ID
## 1            NM_017923, NM_022746  MARCH1
## 2 NM_016496, NM_017898, NM_017898  MARCH2
## 3            NM_178450, NM_178450  MARCH3
## 4                       NM_020814  MARCH4
## 5                       NM_017824  MARCH5
## 6                       NM_005885  MARCH6
columnName <- outlier[i, "colname"]
columnName
## [1] "ID"
checkGeneSymbols(head(gpltable[,columnName]))
##        x Approved Suggested.Symbol
## 1 MARCH1    FALSE          MARCHF1
## 2 MARCH2    FALSE          MARCHF2
## 3 MARCH3    FALSE          MARCHF3
## 4 MARCH4    FALSE          MARCHF4
## 5 MARCH5    FALSE          MARCHF5
## 6 MARCH6    FALSE          MARCHF6
hgnc.vec <- unique(as.character(gpltable[, columnName])) # assumed that there is only one 'symbol' column  
hgnc.vec <- gsub("[ ].+", "", hgnc.vec) # get rid of anything after a space  
HGNChelper.output <- checkGeneSymbols(iconv(hgnc.vec, "latin1", "ASCII", ""),
                                      map = currentHumanMap) # convert to ascii  
## Warning in checkGeneSymbols(iconv(hgnc.vec, "latin1", "ASCII", ""), map =
## currentHumanMap): Human gene symbols should be all upper-case except for the
## 'orf' in open reading frames. The case of some letters was corrected.
## Warning in checkGeneSymbols(iconv(hgnc.vec, "latin1", "ASCII", ""), map =
## currentHumanMap): x contains non-approved gene symbols
notFixed <- which(is.na(HGNChelper.output$Suggested.Symbol))
head(HGNChelper.output[notFixed,])
##                 x Approved Suggested.Symbol
## 27 A_19_P00325768    FALSE             <NA>
## 28 A_19_P00800244    FALSE             <NA>
## 29 A_19_P00802027    FALSE             <NA>
## 30 A_19_P00803499    FALSE             <NA>
## 31 A_19_P00803675    FALSE             <NA>
## 32 A_19_P00804070    FALSE             <NA>

1.3 Mapping not available

  • Missing data
  • lncRNA (long non-coding RNA)
i <- 4   # GPL25261
gpl <- outlier[i, "platform"]
gpldat <- getGEO(filename = file.path(dat_dir, "platforms", paste0(gpl, ".soft")))
gpltable <- Table(gpldat)
head(gpltable)
##              ID Gene ID                               ProbeName
## 1 A_21_P0014386                                   A_21_P0014386
## 2         CPED1   CPED1 A_33_P3396872;A_24_P187799;A_24_P943781
## 3          BCOR    BCOR A_33_P3267760;A_23_P405707;A_23_P159741
## 4         CHAC2   CHAC2                            A_32_P194264
## 5         IFI30   IFI30                            A_23_P153745
## 6 A_33_P3352837                                   A_33_P3352837
##                                     SPOT_ID
## 1                             A_21_P0014386
## 2          NM_001105533;NM_024913;NM_024913
## 3 ENST00000378463;ENST00000615339;NM_017745
## 4                              NM_001008708
## 5                                 NM_006332
## 6                             A_33_P3352837
##                                                                                                                                                                                                                                                                                                                                                   Description
## 1                                                                                                                                                                                                                                                                                                                                                     Unknown
## 2 ref|Homo sapiens cadherin-like and PC-esterase domain containing 1 (CPED1), transcript variant 2, mRNA [NM_001105533];ref|Homo sapiens cadherin-like and PC-esterase domain containing 1 (CPED1), transcript variant 1, mRNA [NM_024913];ref|Homo sapiens cadherin-like and PC-esterase domain containing 1 (CPED1), transcript variant 1, mRNA [NM_024913]
## 3                                                                                                                      ens|BCL6 corepressor [Source:HGNC Symbol;Acc:HGNC:20893] [ENST00000378463];ens|BCL6 corepressor [Source:HGNC Symbol;Acc:HGNC:20893] [ENST00000615339];ref|Homo sapiens BCL6 corepressor (BCOR), transcript variant 1, mRNA [NM_017745]
## 4                                                                                                                                                                                                                                                          ref|Homo sapiens ChaC, cation transport regulator homolog 2 (E. coli) (CHAC2), mRNA [NM_001008708]
## 5                                                                                                                                                                                                                                                                           ref|Homo sapiens interferon, gamma-inducible protein 30 (IFI30), mRNA [NM_006332]
## 6                                                                                                                                                                                                                                                                                                                                                     Unknown
columnName <- outlier[i, "colname"]
columnName
## [1] "Gene ID"
hgnc.vec <- unique(as.character(gpltable[, columnName])) # assumed that there is only one 'symbol' column  
hgnc.vec <- gsub("[ ].+", "", hgnc.vec) # get rid of anything after a space  
HGNChelper.output <- checkGeneSymbols(iconv(hgnc.vec, "latin1", "ASCII", ""),
                                      map = currentHumanMap) # convert to ascii  
notFixed <- which(is.na(HGNChelper.output$Suggested.Symbol))
head(HGNChelper.output[notFixed,])
##                  x Approved Suggested.Symbol
## 1                     FALSE             <NA>
## 6  ENST00000618272    FALSE             <NA>
## 7  ENST00000436258    FALSE             <NA>
## 10    lnc-ARMCX4-1    FALSE             <NA>
## 15    LOC101927502    FALSE             <NA>
## 18     lnc-SOX11-1    FALSE             <NA>

1.4 Withdrawn gene symbol

i <- 5   # GPL16309
gpl <- outlier[i, "platform"]
gpldat <- getGEO(filename = file.path(dat_dir, "platforms", paste0(gpl, ".soft")))
gpltable <- Table(gpldat)
head(gpltable)
##   ID            NAME
## 1  1 GE_BrightCorner
## 2  2      DarkCorner
## 3  3      DarkCorner
## 4  4    A_23_P117082
## 5  5   A_33_P3246448
## 6  6   A_33_P3318220
##                                                    Genebank Accession    GB_ACC
## 1                                                                              
## 2                                                                              
## 3                                                                              
## 4           ref|NM_015987|ens|ENST00000014930|gb|AF117615|gb|BC016277 NM_015987
## 5                     ref|NM_080671|ens|ENST00000281830|tc|THC2655788 NM_080671
## 6 ref|NM_178466|ens|ENST00000375454|ens|ENST00000471233|tc|THC2478474 NM_178466
##   ENSEMBL_ID       Refseq ID     Gene Symbol
## 1            GE_BrightCorner GE_BrightCorner
## 2                 DarkCorner      DarkCorner
## 3                 DarkCorner      DarkCorner
## 4                  NM_015987           HEBP1
## 5                  NM_080671           KCNE4
## 6                  NM_178466          BPIFA3
##                                                                                       Gene Description
## 1                                                                                                     
## 2                                                                                                     
## 3                                                                                                     
## 4                                        Homo sapiens heme binding protein 1 (HEBP1), mRNA [NM_015987]
## 5 Homo sapiens potassium voltage-gated channel, Isk-related family, member 4 (KCNE4), mRNA [NM_080671]
## 6 Homo sapiens BPI fold containing family A, member 3 (BPIFA3), transcript variant 1, mRNA [NM_178466]
##       Chromosome Map Location
## 1                            
## 2                            
## 3                            
## 4  hs|chr12:13127906-13127847
## 5 hs|chr2:223920197-223920256
## 6  hs|chr20:31812208-31812267
##                                                       SEQUENCE SPOT_ID
## 1                                                              CONTROL
## 2                                                              CONTROL
## 3                                                              CONTROL
## 4 AAGGGGGAAAATGTGATTTGTGCCTGATCTTTCATCTGTGATTCTTATAAGAGCTTTGTC        
## 5 GCAAGTCTCTCTGCACCTATTAAAAAGTGATGTATATACTTCCTTCTTATTCTGTTGAGT        
## 6 CATTCCATAAGGAGTGGTTCTCGGCAAATATCTCACTTGAATTTGACCTTGAATTGAGAC
columnName <- outlier[i, "colname"]
columnName
## [1] "Gene Symbol"
hgnc.vec <- unique(as.character(gpltable[, columnName])) # assumed that there is only one 'symbol' column  
hgnc.vec <- gsub("[ ].+", "", hgnc.vec) # get rid of anything after a space  
HGNChelper.output <- checkGeneSymbols(iconv(hgnc.vec, "latin1", "ASCII", ""),
                                      map = currentHumanMap) # convert to ascii  
notFixed <- which(is.na(HGNChelper.output$Suggested.Symbol))
head(HGNChelper.output[notFixed,])
##                  x Approved Suggested.Symbol
## 1  GE_BrightCorner    FALSE             <NA>
## 2       DarkCorner    FALSE             <NA>
## 6     LOC100129869    FALSE             <NA>
## 9     LOC100506844    FALSE             <NA>
## 13            OCLM    FALSE             <NA>
## 20 ENST00000319813    FALSE             <NA>

1.5 Non-human gene symbol

In the example of GPL24307, chicken gene OvoDA3.

1.6 Mixed with others

In the example of GPL23453, mixed with mouse genes, commercial RNAi product name (e.g. V1RF1), etc.