17q12 deletion syndrome mouse model shows defects in craniofacial, brain and kidney development, and glucose homeostasis

ABSTRACT 17q12 deletion (17q12Del) syndrome is a copy number variant (CNV) disorder associated with neurodevelopmental disorders and renal cysts and diabetes syndrome (RCAD). Using CRISPR/Cas9 genome editing, we generated a mouse model of 17q12Del syndrome on both inbred (C57BL/6N) and outbred (CD-1) genetic backgrounds. On C57BL/6N, the 17q12Del mice had severe head development defects, potentially mediated by haploinsufficiency of Lhx1, a gene within the interval that controls head development. Phenotypes included brain malformations, particularly disruption of the telencephalon and craniofacial defects. On the CD-1 background, the 17q12Del mice survived to adulthood and showed milder craniofacial and brain abnormalities. We report postnatal brain defects using automated magnetic resonance imaging-based morphometry. In addition, we demonstrate renal and blood glucose abnormalities relevant to RCAD. On both genetic backgrounds, we found sex-specific presentations, with male 17q12Del mice exhibiting higher penetrance and more severe phenotypes. Results from these experiments pinpoint specific developmental defects and pathways that guide clinical studies and a mechanistic understanding of the human 17q12Del syndrome. This mouse mutant represents the first and only experimental model to date for the 17q12 CNV disorder. This article has an associated First Person interview with the first author of the paper.

Fig. S2.Adult male 17q12Del CD-1 brain malformations vary in severity.Nissl-stained serial sections from representative CD-1 6-week-old brains from wild-type and 17q12Del male mice.(m) brain sections are representative of a mild deletion phenotype, (s) brain sections are representative of a severe deletion phenotype.17q12Del(m) brains (center) have mild ventricular dilatation, mild callosal thinning, and increased brain height.17q12Del(s) brains (right) have profound ventricular dilatation, severe callosal thinning, increased brain height, and severe posterior cortical thinning.Sections are labeled to indicate landmark structure in the approximate region of coronal section; PFC -prefrontal cortex, STR -striatum, AC -anterior commissure, PHF -prehippocampal formation, MID HP -mid-hippocampus, POS HP -posterior hippocampus.Scale bar is 0.5mm.Fig. S3.Adult female 17q12Del CD-1 brain malformations are less prominent than in males.Nissl-stained serial sections from representative CD-1 6-week-old brains from wild-type and 17q12Del female mice.(m) brain sections are representative of a mild deletion phenotype, (s) brain sections are representative of a severe deletion phenotype.The 17q12Del(m) brain (center) has few macroscopic anomalies, though the brain is smaller than wild-type.The 17q12Del(s) brain (right) has asymmetric ventricular dilatation, moderate callosal thinning, increased brain height, and severe posterior cortical thinning.Sections are labeled to indicate landmark structure in the approximate region of coronal section; PFC -prefrontal cortex, STRstriatum, AC -anterior commissure, PHF -prehippocampal formation, MID HP -midhippocampus, POS HP -posterior hippocampus.Scale bar is 0.5mm.
Table S1.Animal numbers for each experiment.Tabulation of all animals used for experiments in this study.Litters for each genotype indicates number of litters where each sexgenotype combination was found.TS16-TS17, with overt abnormalities of the head and/or brain, including two or more of the following: -absence or severe malformation of the telencephalon and/or diencephalon -severe malformation and/or under-differentiation of the midbrain or hindbrain -absence of the lens vesicle or optic invagination Table S2.Severity score categories.≥75% C57BL/6N or CD-1 animals were collected at indicated stage and assessed for abnormal phenotypes.Abnormalities were binned into the above categories and each pup was assigned a severity score.For embryonic animals, Theiler staging was performed with reference to major developmental hallmarks.Developmental delay was determined in reference to average wildtype TS per litter.In brief, for stages where some deletion embryos were developmentally delayed, TS12a and TS12b were differentiated by allantois contact with the embryo, TS13 and TS14 were differentiated by appearance of the forelimb bud and position of the brachial arches, and TS16 and TS17 were differentiated by the shape of the otic vesicle.See Figure 3 for representative embryos for each category.For P0 animals, see Figure 4 for representative offspring for each category, and Figure S1 for representative Nissl sections from category 1 and 2 offspring.For CD-1 animals, see Figure 5

Disease Models & Mechanisms • Supplementary information
Table S3.MRI absolute volume results and statistics.
Click here to download Table S3 Table S4.MRI relative volume results and statistics.
Click here to download Table S4 Table S5.MRI regions and developmental structural ontogeny classifications.
Click here to download Table S5 Table S6.MRI structural ontogeny region volume results and statistics.
Click here to download for craniofacial features, and FiguresS2 and S4for representative Nissl sections from male and female deletion animals.