Maternal UPD
Scheuvens R et al (2017) concluded that clinical features in upd(16)mat are caused by (hidden) trisomy 16 mosaicism and a specific chromosome 16-associated imprinting disorder does not exist.
In contrast, Inoue T et al (2018) proposed that excessive expression of the maternally expressed gene ZNF597 is responsible for the upd(16)mat phenotype.
Previously, maternal UPD of chromosome 16 was associated with intrauterine growth retardation (IUGR) in several cases (Los FJ et al 1998; Lesmana H & Hopkin R 2014, abstracts of the 64th annual meeting of the American Society of Genetics, abstract no. 2785T; Faas BH et al 2010 (Case 21); Yingjun X et al 2017). Imprinting was considered possible based on studies of 26 patients with placental mosaicism for trisomy 16 (Robinson WP et al. 1997) and based on developmental anomalies in a minority of patients (anal atresia, and hypospadius) (Ledbetter DH et al. 1995).
Maternal UPD of chromosome 16 has been associated with haematological disorders. Several cases of maternal UPD of chromosome 16 resulting in haemoglobin Bart’s hydrops fetalis have been identified. Hb Bart’s hydrops fetalis is a severe form of alpha-thalassaemia (Wattanasirichaigoon D et al 2008; Kou KO et al 2014; Au PK et al 2016). Maternal UPD of chromosome 16 has been identified as the cause of Fanconi anaemia in three cases due to the unmasking of recessive mutations (Donovan FX et al 2016).

Paternal UPD
Paternal UPD was associated with very few defects, suggesting an absence of phenotypic effects in the absence of homozygous recessive mutations (Kohlhase J et al 2000).
Donovan FX et al (2016) identified a case of Fanconi anaemia due to paternal UPD, in addition to the three cases of maternal UPD noted above.
Hamvas A et al (2009) identified three cases of paternal UPD of chromosome 16 that revealed mutations in the ABCA3 gene. Homozygosity for these mutations results in pulmonary surfactant deficiency in the newborn period of life.


Disomy (UPD)



Last Modified 9/24/2018


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