Partial 1q Duplications and Associated Phenotype

Abstract

Duplications of the long arm of chromosome 1 are rare. Distal duplications are the most common and have been reported as either pure trisomy or unbalanced translocations. The paucity of cases with pure distal 1q duplications has made it difficult to delineate a partial distal trisomy 1q syndrome. Here, we report 2 patients with overlapping 1q duplications detected by G-banding. Array CGH and FISH were performed to characterize the duplicated segments, exclude the involvement of other chromosomes and determine the orientation of the duplication. Patient 1 presents with a mild phenotype and carries a 22.5-Mb 1q41q43 duplication. Patient 2 presents with a pure 1q42.13qter inverted duplication of 21.5 Mb, one of the smallest distal 1q duplications ever described and one of the few cases characterized by array CGH, thus contributing to a better characterization of distal 1q duplication syndrome.

Familial Duplication/Deletion of 1q42.13q43 as Meiotic Consequence of an Intrachromosomal Insertion in Chromosome 1

“…They found 477 insertional translocations with an incidence of approximately 2.1%, demonstrating that the frequency detected with array-CGH seems to be higher . This result is confirmed by some other recent studies which estimated the frequency of these rearrangements at the submicroscopic level by array-CGH [Bartsch et al, 2001;Williams et al, 2009;Crepel et al, 2010;Rigola et al, 2015;Morris et al, 2016;Wang et al, 2016].…”

“…Most of the reported cases are the results of translocations involving the telomeric regions of chromosomes [Steffensen et al, 1977;Johnson et al, 1985;Watson et al, 1986;Kausch et al, 1988;Johnson, 1991;Ioan et al, 1992;Arai et al, 1994;Concolino et al, 1998;Fan et al, 1999;Bartsch et al, 2001;De Brasi et al, 2001;Gentile et al, 2003;Coccé et al, 2007;Hill et al, 2007;Tuschl et al, 2007;Chen et al, 2010Chen et al, , 2012Tartaglia et al, 2011;Khan et al, 2012;Morris et al, 2016].…”

A case with concurrent duplication, triplication, and uniparental isodisomy at 1q42.12-qter supporting microhomology-mediated break-induced replication model for replicative rearrangements

“…Because partial 1q trisomy is a rare disorder and unbalanced chromosomal translocations are often observed with this alteration [ 11 – 16 ], it is difficult to evaluate the contribution of 1q trisomy to the phenotype in cases involving another chromosome. Patients with pure partial distal trisomy 1q are known to demonstrate a wide range of manifestations of variable severity.…”

Duplication of 1q31.3q41 in two affected siblings due to paternal insertional translocation

“…The clinical features of our patients overlap with some previously reported cases with 1q31.3q41 duplication syndrome in terms of moderate to severe developmental delay, postnatal growth retardation and craniofacial dysmorphism, such as downslanted palpebral fissures, nose abnormalities and a thin upper lip vermilion (figure 5 and table 1). 2 5 A large, interstitial aberration of approximately 30 Mb in the long arm of chromosome 1 which encompasses bands 1q31–1q41 was first described by Sillen et al (1998) in a patient with severe ID, epilepsy and minor abnormalities. Similarly, a 16.7 Mb pure duplication of 1q32.3q42.1 was found in a patient with moderate ID, respiratory and urogenital problems, with some mild anomalies 5…”

“…Partial duplications of the long arm of chromosome 1 are rare and most of the reported cases involve terminal duplications. Some of the cases are due to pure duplications with de novo occurrence,1–5 but most are reported as a result of abnormal segregation of a parental reciprocal translocation 6–8. The clinical features include short stature, intellectual disability (ID) and/or developmental delay, limited to non-verbal speech and multiple dysmorphic features 4 5 7.…”