Zhang XY, Qi J, Shen YQ, Liu X, Liu A, Zhou Z, Han J, Zhang ZC. Mutations of PQBP1 in Renpenning syndrome promote ubiquitin-mediated degradation of FMRP and cause synaptic dysfunction. Hum Mol Genet. 2017 Mar 1;26(5):955-968. PMID: 28073926.
From the abstract: "Renpenning syndrome is a group of X-linked intellectual disability syndromes caused by mutations in human polyglutamine-binding protein 1 (PQBP1) gene. ... In this study, we examine the cellular and synaptic functions of the most common mutations found in the patients ... In Drosophila neuromuscular junction model, PQBP1 c.463_464dupAG transgenic flies showed remarkable defects of synaptic over-growth, which can be rescued by exogenously expressing dFMRP. Our data strongly support a gain-of-function pathogenic mechanism of PQBP1 c.459_462delAGAG and c.463_464dupAG mutations, and suggest that therapeutic strategies to restore FMRP function may be beneficial for those patients."