Intellectual disability and cancer susceptibility in a family with inherited 14q32.13q32.2 deletion.

Abstract

Located in 14q32.13, DICER1 codes for an RNase III endoribonuclease essential in the processing of microRNAs. These microRNAs are functional non-coding RNAs that regulate gene expression at a post-transcriptional level by interfering with translation and degradation of target messenger RNAs. Their deregulations have been implicated in several human diseases and cancers. Germline mutations in DICER1 are associated with a low susceptibility risk to tumor development. Inactivating mutations have been identified in patients and families with various benign and malignant tumors, especially pleuropulmonary blastoma, cystic nephroma and ovarian Sertoli-Leydig tumors. Germline DICER1 deletion has not been reported so far. We report a 7-year-old girl with an inherited DICER1 deletion. She was referred for mild intellectual deficiency, a medical history of cystic nephroma and dysmorphic features. Her father, two paternal uncles and the paternal grandmother had mild to moderate intellectual disabilities. The deceased grandmother had presented uterin and ovarian tumors. Array-CGH analysis identified a 5041kb deletion in 14q32.13-q32.2 in the patient, the father, the two uncles and the paternal grandmother. The deletion contained 50 coding genes and led to DICER 1 haploinsufficiency which was responsible for cancer susceptibility. Moreover, transmission of the deletion was related to intellectual disability in this family. The 14q32.13q32.2 locus has been previously associated with autosomal recessive mental retardation, suggesting the presence in the region of genes implicated in cerebral development and cognitive functions