Hyperphosphatemic familial tumoral calcinosis caused by a novel variant in the GALNT3 gene

Aim Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare endocrine disorder caused by autosomal recessive variants in GALNT3, FGF23, and KL leading to progressive calcification of soft tissues and subsequent clinical effects. The aim of this was to study the cause of HFTC in an Iranian family. Patients and methods Four generations of a family with HFTC were studied for understanding the genetic pattern of the disease. Whole exome sequencing was applied on genomic DNA of the proband. Based on its result, genetically altered sequences were checked in his family through sanger sequencing. Then bioinformatics approaches as well as co-segregation analysis were applied to validate the genetic alteration. Results A novel homozygous variant in exon four of GALNT3, namely p.R261Q was found. The parents and sister were carriers. Conclusion To our knowledge, it is the first-reported Iranian family with GALNT3-CDG novel variant.