Fig. 4

Focus on chromosomal anomalies. A Chromosomal anomalies described (n = 11,950). The unbalanced structural anomalies are mostly described (59.4%, n = 7103) whereas number anomalies only represent 18.8% (n = 2247). B Unbalanced chromosomal anomalies described (n = 7,103). Distal deletion: 22.6% (n = 1603); proximal deletion: 34.9% (n = 2480); distal duplication: 10.2% (n = 724); proximal duplication 17.1% (n = 1218); duplication and deletion (only one chromosome): 3.3% (n = 234); proximal duplication (inserted elsewhere): 0.6% (n = 46); isochromosome: 1.4% (n = 98); Marker: 2.4% (n = 167); Missing data: 2.6% (n = 187); Other: 1.7% (n = 119); ring chromosome: 1.6%(n = 114); partial triplication/tetrasomy: 1.6% (n = 113).C Frequency of implication of each chromosome (n = 12,614). Chromosomal anomalies are more frequent for all acrocentric chromosomes as compared to non-acrocentric chromosomes, the more represented being chromosome 21 (n = 1,086; 8.6%), chromosome 15 (n = 856; 6.7%), and chromosome 22 (n = 849; 6.7%)