Table 1.
Studies using candidate genes involved in different pathways
| Gene name | Gene symbol | Chromosomal location | References |
|---|---|---|---|
| Transcription factors | |||
| Muscle segment homeobox homolog 1 | MSX1 | 4p16.3-p16.1 | 21-23,32,49,123,124 |
| Muscle segment homeobox homolog 2 | MSX2 | 5q34-q35 | 22 |
| T-box transcription factor TBX22 | TBX22 | Xq21.1 | 76,125 |
| Interferon regulatory factor 6 | IRF6 | 1q32.3-q41 | 24 |
| T-box transcription factor TBX10 | TBX10 | 11q13.2 | 22,125 |
| Distal-less homeobox 2 | DLX2 | 2q32 | 126 |
| Distal-less homeobox 3 | DLX3 | 17q21 | 125 |
| SATB homeobox 2 | SATB2 | 2q33 | 22,58,127 |
| RYK receptor-like tyrosine kinase | RYK | 3q22 | 128 |
| Transcription factor AP-2 alpha | TFAP2A | 6p24 | 129 |
| Growth factor | |||
| Transforming growth factor, alpha | TGFα | 2p13 | 17,21,130-132 |
| Transforming growth factor, beta 1 | TGFβ1 | 19q13.1 | 132,133 |
| Transforming growth factor, beta 3 | TGFβ3 | 14q24 | 55,125,126,132,134 |
| V-ski sarcoma viral oncogene homolog | SKI | 1q22-q24 | 22,135 |
| Vibroblast growth factor receptor 1 | FGFR1 | 8p11.2-p11.1 | 61,136 |
| Tumour protein p63 | TP63 | 3q28 | 29,137 |
| Cell signalling | |||
| Poliovirus receptor-related 1 | PVRL1 | 11q23.3 | 71,73,125,131,138 |
| Poliovirus receptor-related 2 | PVRL2 | 19q13.2 | 19 |
| Poliovirus receptor | PVR | 19q13.2 | 19 |
| Patched homolog 1 (Drosophila) | PTCH | 9q22.3 | 139 |
| Gamma-aminobutyric acid a receptor, beta 3 | GABRB3 | 15q11.2-q12 | 34,126,132 |
| Aryl-hydrocarbon receptor nuclear translocator 2 | ARNT2 | 15q24 | 140 |
| Receptor tyrosine kinase-like orphan receptor 2 | ROR2 | 9q22 | 48 |
| Folate pathway | |||
| 5,10-methylenetetrahydrofolate reductase | MTHFR | 1 p36.3 | 119,121,141-143 |
| Methylenetetrahydrofolate dehydrogenase 1 | MTHFD1 | 14q24 | 119,144 |
| 5-methyltetrahydrofolate-homocysteine methyltransferase | MTR | 1q43 | 119,145 |
| 5-methyltetrahydrofolate-homocysteine methyltransferase reductase | MTRR | 5p15.3-p15.2 | 145 |
| Reduced folate carrier | RFC1 | 21q22.3 | 119,146 |
| Folate receptor 1 | FOLR1 | 11q13.3-q14.1 | 72,147 |
| Betaine-homocysteine methyltransferase | BHMT | 5q13.1-q15 | 148 |
| Betaine-homocysteine methyltransferase 2 | BHMT2 | 5q13 | 149 |
| Detoxification | |||
| Cytochrome P450, family 1, subfamily A, polypeptide 1 | CYP1A1 | 15q22-q24 | 150,151 |
| N-acetyltransferase 1 | NAT1 | 8p23.1-p21.3 | 7,152 |
| N-acetyltransferase 2 | NAT2 | 8p22 | 7,151 |
| Glutathione S-transferase M1 | GSTM1 | 1p13.3 | 4 |
| Glutathione S-transferase theta 1 | GSTT1 | 22q11.23 | 4,151 |
| Glutathione S-transferase pi | GSTP1 | 11 q13 | 153 |
| Retinoic acid receptor, alpha | RARA | 17q21 | 6,154-156 |
| Epoxide hydrolase 1, microsomal | EPHX1 | 1q42.1 | 153 |