Table 1.

Selected disorders involving parent-of-origin effects

Condition	POE Mechanism	Specific POE Effect	Phenotype	Selected References
Transient neonatal diabetes mellitus	Paternally imprinted chromosome 6q24	Paternal duplication or paternal UPD of chromosome 6q24, methylation defect of maternal ZAC/HYMAI	Diabetes mellitus occurring before one week of age and resolving by three months	Temple and Shield (2002) [22] Mackay et al (2005) [27]
Beckwith- Wiedemann syndrome	Imprinted chromosome 11p15.5	Complex variety of mechanisms including maternal germline CDKN1C mutations, mosaic paternal UPD 11p15.5, loss of maternal imprinting of IGF2, loss of maternal expression of H19, deletion of paternal LIT1	Numerous features including overgrowth, macroglossia, abdominal wall defects, embryonic tumors	Engel et al (2000) [67] Niemitz et al (2004) [68]
Prader-Willi syndrome	Imprinted chromosome 15q11-13	Paternal deletion 15q11- 13, maternal UPD 15q11- 13, imprinting defect 15q11-13	Neonatal hypotonia/failure to thrive, hyperphagia, obesity, hypogonadisim, short stature, small hands/feet, mild mental retardation	Nicholls et al (1998) [69]
Angelman syndrome	Imprinted chromosome 15q11-13	Maternal deletion 15q11- 13, paternal UPD 15q11- 13 (rare), imprinting defect 15q11-13	Ataxia, tremor, seizures, sleep disorder, severe mental retardation, happy/laughing affect	Nicholls et al (1998) [69]
Albright hereditary osteodystrophy	Paternally imprinted chromosome 20q13	GNAS1 mutation; maternally transmitted AHO cases additionally have multiple hormone resistance due to tissue- specific paternal GNAS1 imprinting	Short stature, obesity, developmental delay, skeletal abnormalties ± multiple hormone resistance	Weinstein et al (2001) [70]
Russell-Silver syndrome (approximately 10% of cases)	Maternally imprinted chromosome 7	Maternal UPD 7	Short stature, asymmetry, triangular face	Hannula et al (2002) [71]
Maternally inherited diabetes and deafness	Maternal inheritance via mitochondrial genome	Mitochondrial 3243 A➔ G mutation	Early onset non- insulin requiring diabetes without obesity, neurosensory hearing loss	Guillausseau et al (2001) [38]
Maturity Onset Diabetes of the Young 2 (MODY2) and birthweight	Maternal intrauterine effects	Maternal glucokinase (GCK) mutation associated with gestational diabetes mellitus and high offspring birth weight, fetal GCK mutation associated with low birth weight, maternal/fetal concordance for GCK mutation associated with normal birth weight	MODY2: Modestly elevated fasting blood glucose, susceptibility to gestational diabetes and diabetes with minimal complications	Hattersley et al (1998) [34]