Chromosome 7 abnormalities in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) heralds a poor prognosis. However its prevalence, morphological characteristics and clinical impact in MDS and AML in Indian subcontinent is sparsely reported. This was an observational cross-sectional study performed to evaluate the clinico-pathological profiles of MDS/AML patients with chromosome 7 abnormalities over a period of 4 years. 724 cases of MDS (n = 150) and AML (n = 574) were evaluated. Abnormal karyotype was detected in 49% (43/88) patients of MDS and 44% (127/289) cases of AML. Chromosome 7 abnormalities were detected in 18% cases of MDS (16/88) and 6.5% (19/289) cases of AML. Sole chromosome 7 abnormalities were detected in 5.7% (5/88) and 2.7% (8/289) and in adjunct to complex abnormalities in 7.9 and 3.1% cases of MDS and AML respectively. Morphologically, dyserythropoiesis, dysmyelopoiesis and eosinophilia were seen in 100, 66 and 56% cases of MDS and 38, 40 and 21% cases of AML. Majority of the patients had an aggressive natural course and outcome was dismal. Chromosome 7 abnormalities are strongly associated with the presence of morphological dysplasia and eosinophilia, irrespective of the type of aberration. It is invariably associated with very poor outcome.

Partial monosomy of the long arm of chromosome 7 has been characterized by wide phenotypic manifestations, but holoprosencephaly (HPE) and sacral agenesis have frequently been associated with this chromosomal deletion. A clear relationship between genotype and phenotype remains to be defined in the 7q deletion syndrome. Three patients (1, 2, and 3) were investigated with 7q terminal deletion and compared with similar deletion cases in the literature in order to stratify the phenotypes associated with 7q35 and 7q36 terminal deletion patients. Patients 1, 2, and 3 were carrying a de novo terminal deletion at bands 7q36.2, 7q35, and 7q36.1, respectively. In patient 3, a small Xq28 duplication was also identified by array-CGH. Our patients presented with heterogeneous phenotypic manifestations, which could imply the possible role of environmental factors (multifactorial inheritance), structural variations in the non-coding regions, penetrance, and/or polymorphism. The varying length of deletion was also taken into account. Growth retardation was the most frequent symptom found in both 7q35 and 7q36 patients we reviewed. The occurrence of HPE and sacral malformation together was seen in less than 10% of the reviewed cases in both kinds of deletion. HPE was associated mainly in cases with an unbalanced translocation.