A Novel Homozygous Missense Variant in the LRRC32 Gene Is Associated With a New Syndrome of Cleft Palate, Progressive Vitreoretinopathy, Growth Retardation, and Developmental Delay.

Cleft lip and/or cleft palate are a common group of birth defects that further classify into syndromic and non-syndromic forms. The syndromic forms are usually accompanied by additional physical or cognitive abnormalities. Isolated cleft palate syndromes are less common; however, they are associated with a variety of congenital malformations and generally have an underlying genetic etiology. A single report in 2019 described a novel syndrome in three individuals, characterized by cleft palate, developmental delay and proliferative retinopathy due to a homozygous non-sense mutation in the LRRC32 gene encoding glycoprotein A repetitions predominant (GARP), a cell surface polypeptide crucial for the processing and maturation of transforming growth factor ß (TGF-ß). We describe a patient who presented with cleft palate, prenatal and postnatal severe growth retardation, global developmental delay, dysmorphic facial features and progressive vitreoretinopathy. Whole exome sequencing (WES) revealed a very rare homozygous missense variant in the LRRC32 gene, which resulted in substitution of a highly conserved isoleucine to threonine. Protein modeling suggested this variant may negatively affect GARP function on latent TGF-ß activation. In summary, our report further expands the clinical features of cleft palate, proliferative retinopathy and developmental delay syndrome and emphasizes the association of LRRC32 pathogenic variants with this new syndrome.

ATP-dependent RNA helicase domain of the ZC3H41 protein from Trypanosoma brucei: expression, purification and crystallization.

A fragment of the Trypanosoma brucei ZC3H41 protein encompassing the ATP-dependent RNA helicase domain was successfully subcloned for expression in a bacterial system (Escherichia coli). Following expression, the protein was purified and crystallized using the vapor-diffusion method. The protein crystals were optimized at a 1:1 protein:reservoir solution ratio using PPGBA 2000. The optimized crystals diffracted to a dmin of 3.15 Å. The collected data revealed preliminary structural information regarding this newly discovered protein.