Homozygous stop-gain variant in LRRC32, encoding a TGFβ receptor, associated with cleft palate, proliferative retinopathy, and developmental delay.

The transforming growth factor-beta (TGFβ) signaling pathway is essential for palatogenesis and retinal development. Glycoprotein A repetitions predominant (GARP), encoded by LRRC32, is a TGFβ cell surface receptor that has been studied primarily in the context of cellular immunity. We identified a homozygous stop-gain variant in LRRC32 (c.1630C>T; p.(Arg544Ter)) in two families with developmental delay, cleft palate, and proliferative retinopathy. Garp-null mice have palate defects and die within 24 h after birth. Our study establishes LRRC32 as a candidate disease-associated gene in humans and lends further support to the role of the TGFβ pathway in palatogenesis and retinal development.