Fig. 7. Genomic variants in LAMA5 affect BM structure and function.

(A) Top: Genetic pedigree for a 100KGP family carrying two LAMA5 pLoF variants. Bottom: Phenotypic abnormalities observed in two LAMA5 variant–carrying fetuses (19- and 20-week gestation) represented as bolded HPO terms. (B) Top: LAMA5 genomic structure and variant locations. Bottom: In vitro minigene splicing assay demonstrating altered splicing of LAMA5 variant 1b. (C) Left: Picrosirius red/Fast Green staining of the 19-week dysplastic kidney; asterisks indicate cysts. Boxed area is magnified on the right; arrowhead and arrows denote abnormal glomerulus and tubules, respectively. Scale bars, 5 mm (left) and 100 μm (right). (D) Pan-laminin (LAM; magenta) and laminin β2 (LAMB2; green) immunofluorescence in normal (left) and dysplastic (right) fetal kidney sections. Asterisks indicate laminin surrounding a cyst. Boxed regions are magnified below. Arrowheads, see text. Scale bars, 50 μm. Full uncropped images are available on figshare: 10.6084/m9.figshare.c.5662348. (E) Bright-field images of zebrafish tail regions (dashed lines) in control^gRNA- and lama5^gRNA-injected 4-dpf embryos. Arrowheads highlight reduced fin fold extension in lama5 crispants. Scale bars, 100 μm. (F) TEM of gut and kidney BMs (yellow arrowheads) in control and lama5 crispants. Boxed regions are magnified in insets. Red arrows indicate BM morphological irregularities. Scale bars, 2 μm (gut) and 1 μm (kidney). (G) Proteinuria in control versus lama5 crispants (n = 24 each). ***P < 0.001, unpaired Student’s t test. For boxplots, edges indicate the 25th and 75th percentiles, the line in the box represents the median, and whiskers mark the minimum and maximum values.