Detailed analysis of 26 cases of 1q partial duplication/triplication syndrome

Abstract

Partial 1q trisomy syndrome is a rare disorder. Because unbalanced chromosomal translocations often occur with 1q trisomy, it is difficult to determine whether patient symptoms are related to 1q trisomy or other chromosomal abnormalities. The present study evaluated genotype-phenotype correlations of 26 cases diagnosed with 1q partial trisomy syndrome. DNA microarray was used to investigate the duplication/triplication region of 16 cases. Although there was no overlapping region common to all 26 cases, the 1q41-qter region was frequently involved. One case diagnosed as a pure interstitial trisomy of chromosome 1q by G-banded karyotype analysis was instead found to be a pure partial tetrasomy by CytoScan HD Array. In four 1q trisomy syndrome cases involving translocation, the translocated partner chromosome could not be detected by DNA microarray analyzes despite G-banded karyotype analysis, because there were a limited number of probes available for the partner region. DNA microarray and G-banded karyotyping techniques were therefore shown to be compensatory diagnostic tools that should be used by clinicians who suspect chromosomal abnormalities. It is important to continue recruiting affected patients and observe and monitor their symptoms to reveal genotype-phenotype correlations and to fully understand their prognosis and identify causal regions of symptoms.

Rehabilitation Treatment of a Child Diagnosed With Duplication of 1q42-q44: A Case Report

“…In addition, anomalies of eyes, ears, nose, and mouth and recurrent respiratory tract infection are common regardless of the translocation among those patients. The patient in our study had duplication of the similar locus, thus showing symptoms similar to those of a previous study [8]. …”

“…Such anomalies could not be found on the abdominal ultrasound or CT scan of the patient in our case. Watanabe et al [8] have reported that chromosomal translocation can be often found in 1q partial duplication/triplication syndrome cases with 1q41-qter being the most frequently involved region. In addition, anomalies of eyes, ears, nose, and mouth and recurrent respiratory tract infection are common regardless of the translocation among those patients.…”

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

“…Patients with pure partial distal trisomy 1q are known to demonstrate a wide range of manifestations of variable severity. However, distal 1q duplication syndrome is characterized by the signs present in many of the previously reported cases [15, 16]. The present case showed some of the symptoms characteristic of distal 1q duplication syndrome, such as psychomotor developmental delay, cardiac defect, widely spaced eyes, a down-slanted palpebral fissure, low-set ear, a prominent forehead, club feet, and scoliosis, although psychomotor developmental delay and cardiac defect were very severe compared with those in previously reported cases and some features commonly found elsewhere were not observed [15, 16].…”

“…However, distal 1q duplication syndrome is characterized by the signs present in many of the previously reported cases [15, 16]. The present case showed some of the symptoms characteristic of distal 1q duplication syndrome, such as psychomotor developmental delay, cardiac defect, widely spaced eyes, a down-slanted palpebral fissure, low-set ear, a prominent forehead, club feet, and scoliosis, although psychomotor developmental delay and cardiac defect were very severe compared with those in previously reported cases and some features commonly found elsewhere were not observed [15, 16]. Because the present patient is the first known case of pure distal partial 1q tetrasomy and trisomy, it is possible that the copy number increase in some of the genes located between 1q42.12 and the middle of 1q43 (approximately 180 RefSeq genes) contributes to these symptoms, although no causal regions responsible for each symptom of distal trisomy/tetrasomy 1 syndrome have been clarified.…”

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

“…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.…”