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Duplication of segment 1p21 following paternal insertional translocation, ins(6;1)(q25;p13.3p22.1)
A Utkus1, I Sorokina, V Kucinskas
1Human Genetics Center, University of Vilnius, Lithuania.
Insights
A rare genetic condition, 1p duplication syndrome, was identified in a young boy with developmental delays and minor physical anomalies. This case highlights a unique familial translocation and its unusual presentation.
Area of Science:
- Genetics
- Pediatrics
- Medical Diagnostics
Background:
- A 3-year-old boy presented with moderate intellectual disability and several minor physical anomalies.
- Cardiac sonography revealed an unusual finding of a chorda traversing the left ventricle.
- Cytogenetic analysis was performed to investigate the underlying cause of the patient's condition.
Purpose of the Study:
- To investigate the genetic basis of the patient's developmental delay and physical anomalies.
- To characterize a novel familial chromosomal translocation involving segments of chromosome 1 and 6.
- To compare the patient's phenotype with previously reported cases of 1p duplication.
Main Methods:
- Clinical examination and assessment of physical anomalies.
- Cardiac sonography for cardiac evaluation.
- Cytogenetic investigation including family studies to identify chromosomal abnormalities.
Main Results:
- The patient exhibited minor anomalies (prominent forehead, flat occiput, exophthalmos, large ears, high arched palate, umbilical hernia, sacral dimple, irregular toes).
- Cytogenetic analysis revealed a duplication of 1p13.3-->p22.1 in the proband, resulting from unbalanced segregation of a balanced insertional translocation (1;6) in the father.
- This specific interstitial duplication of 1p is novel and the patient's mild phenotype is remarkable compared to other reported cases.
Conclusions:
- The study identified a rare familial chromosomal duplication (1p13.3-->p22.1) associated with moderate intellectual disability and minor anomalies.
- The findings suggest that the size and specific breakpoints of interstitial 1p duplications may influence phenotypic expression.
- This case expands the understanding of chromosomal abnormalities and their variable clinical manifestations in genetic disorders.
Abstract:
A moderately mentally retarded 3 year old boy showed minor anomalies including a prominent forehead and flat occiput, exophthalmos, large and prominent ears, high arched palate, umbilical hernia, sacral dimple, and irregular position of the toes. Cardiac sonography disclosed a chorda running through the left ventricle. Cytogenetic investigation of the family showed a balanced insertional translocation of segment 1p13-->p22 into distal 6q in the father which had led, through unbalanced segregation, to duplication of 1p13.3-->p22.1 in the proband. Familial duplication of such a small interstitial segment of 1p has not been reported previously, and the paucity of abnormal physical findings in the proband compared to previous patients with a similar aberration is remarkable.