TY  - JOUR
AU  - Bouchahta, Hicham
AU  - Benyahya, Nada
AU  - EL Amrani, Zhour
AU  - Ouboukss, Fatima
AU  - Liehr, Thomas
AU  - Elalaoui, Siham Chafai
AU  - Carreira, Isabel Marques
AU  - Doubaj, Yassamine
AU  - Natiq, Abdelhafid
AU  - Sbabou, Laila
PY  - 2026
DA  - 2026/05/19
TI  - Clinical and Molecular Cytogenetic Characterization of a <i>De Novo</i> 3q26.33-q28 Duplication: Case Report and Literature Review
JO  - OBM Genetics
SP  - 341
VL  - 10
IS  - 02
AB  - Isolated duplications of the long arm of chromosome 3 (3q) are rare chromosomal abnormalities. To date, approximately 32 pure cases have been documented. Most reported 3q duplications arise from unbalanced translocations or inversion-loops mechanisms and are associated with additional chromosomal imbalances, making pure duplications particularly valuable for genotype-phenotype correlations. We report a 17-year-old female with a de novo pure tandem duplication of 3q26.33-q28 (~10.945 Mb). The clinical course was marked by neonatal distress with hypotonia, severe global developmental delay (independent walking at 24 months, language acquisition at 4 years), intellectual disability, autism spectrum disorder, and epilepsy. Dysmorphic features included esotropia, thin upper lip, high arched eyebrows, flat occiput, short neck, and generalized hirsutism. Notably, the patient exhibited increased birth weight (4000 g), contrasting with the growth retardation commonly described in 3q duplication syndrome, and no congenital cardiac anomalies were detected. Conventional R-banded karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray analysis (CMA) were performed on peripheral blood samples from the patient and both parents. Karyotype analysis revealed 46, XX, add(3)(q?). CMA identified a duplication defined as arr[GRCh37] 3q26.33q28(179,659,847_190,604,567) × 3. FISH analysis confirmed the tandem configuration of the duplicated segment. Parental karyotypes were normal, supporting a de novo origin of the rearrangement. The duplicated region encompasses 31 OMIM morbid genes, including SOX2, IGF2BP2 and TP63. This case represents the first reported pure 3q duplication since a 2023 comprehensive review, which documented 31 cases. The phenotypic profile suggests region-specific contributions to the 3q duplication syndrome phenotype. This case provides a refined genotype-phenotype correlation and underscores the diagnostic value of an integrated cytogenetic approach combining conventional and molecular techniques.
SN  - 2577-5790
UR  - https://doi.org/10.21926/obm.genet.2602341
DO  - 10.21926/obm.genet.2602341
ID  - Bouchahta2026
ER  -