Fig. 1

a Pedigree of patient 1 with a likely pathogenic OSGEP variant, c.81C > G p.(Asn27Lys), in homozygosity while his consanguineous parents are healthy heterozygous carriers. b The identified missense variant c.81C > G p.(Asn27Lys) affects a totally conserved amino acid N27 in OSGEP orthologs. c Silver-stained renal biopsy from patient 1 showed glomerular collapse with mesangial matrix increase, atrophic tubules, and interstitial fibrosis on light microscopy. d CMRI performed in patient 1 at 8 months of age: sagittal 3 Dimensional Imaging T1 sequence (a), axial reconstructions (b–e), and axial Turbo Spin Echo (TSE) T2 (f–j). k–o: Sequence TSE T2 of normal control individual. MRI revealed craniofacial disproportion in relation to microcephaly (a); supratentorial cortico-subcortical atrophy with increased extra-axial space, prominence of the frontal horns, and thinning of the corpus callosum (red arrow in a); bilateral subdural frontoparietal hygromas (red asterisks in h–j); and atrophy of the basal ganglia (h). A decrease in the number and depth of the grooves was observed (h–j) and there was an absence of normal myelination of the brainstem (red arrow in f), cerebellar peduncles (blue arrow in f), internal capsules (red arrow in h), and white bihemispheric substance (arrows in i and j). Hypointense T2 signal of the thalamus was evident (blue arrow in h). Enucleation of the left eye is denoted by the yellow arrow in f. Finally, there was an increase in the thickness of the cranial and facial subcutaneous cellular tissue (green arrows in a and b)