Constitutional Partial Proximal Trisomy 14q11.2 to 14q21: Two New Moroccan Cases and Review of the Literature

Abstract

Small supernumerary marker chromosomes (sSMCs), a major problem in clinical cytogenetics, are too small to be characterized for their chromosomal origin by cytogenetic banding techniques. Most sSMCs have not yet been correlated with a specific clinical syndrome, and genotype-phenotype correlation in sSMC patients is still very much under development. In this paper, we report two new Moroccan cases with polymalformative syndrome in which we identified similar but not identical sSMCs derived from chromosome 14; in one case a +del(14)(q21.1) and a +del(14)(q21.2) in the other. To the best of our knowledge, such de novo proximal partial trisomies 14 have previously been reported in Keywords Polymalformative syndrome; karyotyping; small supernumerary marker chromosomes (sSMCs); fluorescence in situ hybridization (FISH); partial trisomy 14q21; tumor risk.

A maternally derived complex small supernumerary marker chromosome involving chromosomes 8 and 14: case report and review of the literature

“…As shown in Table 1 several clinical features such as growth delay, psychomotor development delay, hypotonia, facial dysmorphia, microcephaly, umbilical hernia were found in our proband and in patients with partial trisomy 8 and 14. We suggest that the predominant clinical features observed in our patient result mainly from trisomy 14q, as they are similar to pure proximal partial trisomy 14q cases (Merhni et al, 2019) also included in Table 1. Parts of clinical variability noted between the five patients could be due to the additional abnormalities observed, like trisomy 8p.…”