Table 1.
Overview of different imprinting disorders in humans
| Imprinting disorder | Imprinted domain | Cytogenetic abnormality | Uniparental disomy | Imprinting center epimutation | Deletions/duplications involving imprinting center | Gene mutation | MLID | References |
|---|---|---|---|---|---|---|---|---|
| Transient neonatal diabetes 1 (TNDM1, OMIM 601410) | 6q24 | Visible paternal duplication of 6q24 (2%) | Paternal UPD6 (35–40%) | Hypomethylation of the maternal ICR/P1 (20%) | Submicroscopic duplication of the 6q24 region on the paternal allele (35–40%) | Reported | [45, 51–53] | |
| Silver–Russell syndrome (SRS, OMIM 180860) | 11p15.5 | Maternal duplication of 11p15 (<2%) | Maternal UPD11 (1 case) | Hypomethylation of the paternal IC1 (up to 70%) | IC2 duplication on maternal allele (1 case) | Reported | [54–59] | |
| 7p12.2, 7q32.2 | Chromosomal rearrangement (<2%) | Maternal UPD7 (5%) | ||||||
| Beckwith–Wiedemann syndrome (BWS, OMIM 130650) | 11p15.5 | Chromosomal rearrangement (1–2%) | Paternal UPD11 (20%) | • Hypermethylation of the maternal IC1 (5%) • Hypomethylation of the maternal IC2 (50%) |
• IC1 deletion on maternal allele (<5%) • IC2 deletion on maternal allele (<2%) |
CDKN1C on maternal allele (5% sporadic, 50% in familial cases) | Reported | [29, 46, 60–65] |
| Prader–Willi Syndrome (PWS, OMIM 176270) | 15q11–q13 | • Deletions of 15q11.2–q13 on maternal allele (65–75%) • Chromosomal rearrangement (<1%) |
Maternal UPD15 (25–30%) | • 1% of PWS is due to imprinting defects (epimutations) • Hypermethylation of paternal PWS/ICR (75–80% of imprinting defects cases) |
Deletions in the regulatory region located around PWS/ICR on the paternal allele (15% of imprinting defect cases) | Not reported | [66–70] | |
| Angelman syndrome (AS, OMIM 105830) | 15q11–q13 | Deletions of 15q11.2–q13 on maternal allele (70%) Chromosomal rearrangement (<1%) |
Paternal UPD15 (7%) | • 2–5% of AS is due to imprinting defects (epimutations) • Hypomethylation of the SNRPN DMR on the maternal allele (80–90% of imprinting defects cases |
Deletions in the regulatory region located around AS/ICR on the maternal allele (10–20% of imprinting defect cases) | UBE3A on maternal allele (11%) | Reported once | [66, 67, 71–75] |
| Pseudohypoparathyroidism type 1b (PHP1B, OMIM 603233) | 20q13 | Microdeletion in STX16 (in about 20% of PHP1B patients with exon 1A ICR hypomethylation) | Paternal UPD20 (few cases reported) | Hypomethylation of ICR of exon 1A on the maternal allele (sporadic cases) | Deletion in NESPAS and NESP55 (very few familial cases) | Reported | [47, 48, 76–82] |