A de novo deletion in a boy with cerebral palsy suggests a refined critical region for the 4q21.22 microdeletion syndrome
AMERICAN JOURNAL OF MEDICAL GENETICS PART A
Authors: Zarrei, Mehdi; Merico, Daniele; Kellam, Barbara; Engchuan, Worrawat; Scriver, Tara; Jokhan, Rikash; Wilson, Michael D.; Parr, Jeremy; Lemire, Edmond G.; Stavropoulos, Dimitri J.; Scherer, Stephen W.
Abstract
We present an 18-year-old boy with cerebral palsy, intellectual disability, speech delay, and seizures. He carries a likely pathogenic 1.3Mb de novo heterozygous deletion in the 4q21.22 microdeletion syndrome region. He also carries a 436kb maternally-inherited duplication impacting the first three exons of CHRNA7. The majority of previously published cases with 4q21.22 syndrome shared common features including growth restriction, muscular hypotonia, and absent or severely delayed speech. Using copy number variation (CNV) data available for other subjects, we defined a minimal critical region of 170.8kb within the syndromic region, encompassing HNRNPD. We also identified a larger 2Mb critical region encompassing ten protein-coding genes, of which six (PRKG2, RASGEF1B, HNRNPDL, HNRNPD, LIN54, COPS4) have a significantly low number of truncating loss-of-function mutations. Long-range chromatin interaction data suggest that this deletion may alter chromatin interactions at the 4q21.22 microdeletion region. We suggest that the deletion or misregulation of these genes is likely to contribute to the neurodevelopmental and neuromuscular abnormalities in 4q21.22 syndrome.
Competing Repressive Factors Control Bone Morphogenetic Protein 2 (BMP2) in Mesenchymal Cells
JOURNAL OF CELLULAR BIOCHEMISTRY
Authors: Fotinos, Anastasios; Fritz, David T.; Lisica, Steven; Liu, Yijun; Rogers, Melissa B.
Abstract
The amount, timing, and location of bone morphogenetic protein 2 (BMP2) synthesis influences the differentiation of pluripotent mesenchymal cells in embryos and adults. The BMP2 3'untranslated region (3'UTR) contains a highly conserved AU-rich element (ARE) embedded in a sequence that commonly represses gene expression in mesenchymal cells. Computational analyses indicate that this site also may bind several microRNAs (miRNAs). Although miRNAs frequently target AU-rich regions, this ARE is unusual because the miRNAs directly span the ARE. We began to characterize the factors that may regulate Bmp2 expression via this complex site. The activating protein HuR (Hu antigen R, ELAVL1, HGNC:3312) directly binds this ARE and can activate gene expression. An miRNA was demonstrated to reverse HuR-mediated activation. Mutational and RNA-interference evidence also supports an AUF1 (AU-factor-1, HNRNPD, HGNC: 5036) contribution to the observed repressive activity of the 3'UTR in mesenchymal cells. A limited number of studies describe how miRNAs interact with ARE-binding proteins that bind adjacent sites. This study is among the first to describe protein/miRNA interactions at the same site. (C) 2015 Wiley Periodicals, Inc.