14q32.3-qter trisomic segment: a case report and literature review

Abstract

Background: Segmental duplication of the long arm of chromosome 14 (14q) has commonly been reported to affect the proximal segment of 14q, while distal duplication is a rare condition and often associated with segmental monosomy of other chromosomes.

Case presentation: We report the clinical and genetic characterization of a 4-year-old male patient with 14q32.3-qter trisomy resulting from an adjacent segregation of a paternal reciprocal translocation (14;21)(q32.1;p12). The child shows minor facial anomalies, severe developmental delay, growth retardation, and a history of congenital hypothyroidism and neonatal transitory hyperglycemic crises.

Conclusions: To the best of our knowledge, only 15 other cases of segmental 14q trisomy were documented. We compared molecularly defined cases to identify a minimal common duplicated region and to find genes with a hypothetical role in the phenotype. The presented case supports the previous suggestion of a pure "distal 14q partial duplication" and underlines the clinical variability.

Keywords: 14q32.3-qter duplication; Array-CGH; Translocation (14; 21).

Fig. 1

Facial features of the patient at different ages compared with literature reported faces

Fig. 2

Cytogenetic, FISH and array-CGH studies. a Proband’s QFQ-banded chromosomes 14 and 21; the arrow shows the derivative 21. b FISH with subtelomeric 14q probe of the proband: the der(21) is arrowed. c Father’s QFQ-banded partial metaphase with two derivative chromosomes arrowed. d Father’s GTG-banded partial metaphase with two derivative chromosomes arrowed. e FISH with subtelomeric 14q probe of the father: hybridization signals are present on the normal 14 and on der(21). f Chromosome 14 view showing the duplication in array-CGH (left) and a schematic representation of supposed NAHR mechanism for translocation formation (right)

Fig. 3

Minimal common duplicated region. Comparison of duplicated region of 9 molecularly defined cases (blue bars). All regions were converted in hg19 genome version. Vertical red bars indicate the minimal overlapping region in 8 out of 9 cases. The only case not overlapping is that described by Chen et al. [11] having a normal phenotype at 6 months of age