SLX4 and Rubinstein-Taybi syndrome: Chromosome 16p13.3 Contiguous Gene Deletion Syndrome including the <i>SLX4</i>, <i>DNASE1</i>, <i>TRAP1</i>, and <i>CREBBP</i> Genes Presenting as a Relatively Mild Rubinstein-Taybi Syndrome Phenotype: A Case Report of a Saudi Boy.