UPD(14)mat and UPD(14)mat in concomitance with mosaic small supernumerary marker chromosome 14 in two new patients with Temple syndrome

Abstract

Temple syndrome (TS14) can be originated by maternal uniparental disomy (UPD(14)mat), paternal deletion, or epimutation, leading to disturbances in 14q32.2 imprinted region. The most frequent phenotypic manifestations are prenatal and postnatal growth failure, hypotonia, developmental delay, small hands/feet, precocious puberty, and truncal obesity. However, the diagnosis can be challenging due to the clinical overlap with other imprinting disorders such as Silver-Russell or Prader-Willi syndromes. Although rare, TS14 has been also reported in patients with concomitant UPD(14)mat and mosaic trisomy 14. In the present report, the clinical and genetic profiles of two new patients with TS14 are described. SNParray and MS-MLPA, allowed the determination of segmental UPD(14)mat and the hypomethylation of MEG3 gene. Additionally, in one of our patients we also observed by cytogenetics a small supernumerary marker chromosome that led to partial trisomy 14 in mosaic. Only few patients with concomitant UPD(14)mat and mosaic partial trisomy 14 have been reported. Our patients share cardinal TS14 phenotypic features that are associated to the genetic abnormalities detected; however, we also observed some clinical features such as fatty liver disease that had not previously been reported as part of this syndrome. The detailed clinical, cytogenetical and molecular description of these two new patients, contributes to a more accurately delineation of this syndrome.