“…A number of microRNAs (miRs), which are small non-coding RNAs (21–25 nucleotides) that regulate the expression of target genes at the post-transcriptional level ( Hudder and Novak, 2008 ; Hou et al, 2011 ), play important roles in a wide array of cellular functions during the development of various tissues, including the upper lip and the palate ( Shin et al, 2012 ; Seelan et al, 2014 ; Warner et al, 2014 ; Mukhopadhyay et al, 2019 ). For instance, loss of a miR-processing enzyme, such as DROSHA and DICER, results in craniofacial developmental defects in mice ( Zehir et al, 2010 ; Nie et al, 2011 ; Schoen et al, 2017 ), and polymorphisms in DROSHA are associated with risk of CL/P in humans ( Xu et al, 2018 ). In addition, mice with a deletion of miR-17-92 cluster, which is located on chromosome 14 in mice and chromosome 13 in humans, exhibit either bilateral or unilateral CLP and delayed endochondral ossification, hypoplastic lung, and cardiac ventricular septal defect ( Ventura et al, 2008 ; de Pontual et al, 2011 ; Wang et al, 2013 ).…”