Cystic kidney diseases associated with mutations in phosphomannomutase 2 promotor: a large spectrum of phenotypes

• Published in: Pediatric nephrology (Berlin, West) West), 2021-08, Vol.36 (8), p.2361-2369
• Main Authors: Dorval, Guillaume, Jeanpierre, Cécile, Morinière, Vincent, Tournant, Carole, Bessières, Bettina, Attié-Bittach, Tania, Amiel, Jeanne, Spaggari, Emmanuel, Ville, Yves, Merieau, Elodie, Gubler, Marie-Claire, Saunier, Sophie, Heidet, Laurence
• Format: Article
• Language: English
• Subjects: Children; Congenital Hyperinsulinism; Exons; Fetuses; Gene mutations; Genetic aspects; Glycosylation; Humans; Hypoglycemia; Kidney diseases; Medicine; Medicine & Public Health; Mutation; Nephrology; Original Article; Pancreas; Pediatric research; Pediatrics; Phenotype; Phenotypes; Phosphomannomutase; Phosphotransferases (Phosphomutases); Polycystic kidney; Polycystic kidney disease; Polycystic Kidney Diseases; Promoter Regions, Genetic; Promoters (Genetics); Renal failure; Risk factors; Syndrome; Urology
• ISSN: 0931-041X; 1432-198X
• DOI: 10.1007/s00467-021-04953-9

Background Co-occurrence of polycystic kidney disease and hyperinsulinemic hypoglycemia has been reported in children in a few families associated with a variant in the promotor of the PMM2 gene, at position -167 upstream of the coding sequence. PMM2 encodes phosphomannomutase 2, a key enzyme in N-glycosylation. While biallelic coding PMM2 mutations are involved in congenital disorder of glycosylation CDG1A, that particular variant in the promoter of the gene, either in the homozygous state or associated with a mutation in the coding exons of the gene, is thought to restrict the N-glycosylation defect to the kidney and the pancreas. Methods Targeted exome sequencing of a panel of genes involved in monogenic kidney diseases. Results We identified a PMM2 variant at position -167 associated with a pathogenic PMM2 variant in the coding exons in 3 families, comprising 6 cases affected with a cystic kidney disease. The spectrum of phenotypes was very broad, from extremely enlarged fetal cystic kidneys in the context of a COACH-like syndrome, to isolated cystic kidney disease with small kidneys, slowly progressing toward kidney failure in adulthood. Hypoglycemia was reported only in one case. Conclusion These data show that the PMM2 promotor variation, in trans of a PMM2 coding mutation, is associated with a wide spectrum of kidney phenotypes, and is not always associated with extra-renal symptoms. When present, extra-renal defects may include COACH-like syndrome. These data prompt screening of PMM2 in unresolved cases of fetal hyperechogenic/cystic kidneys as well as in cystic kidney disease in children and adults. Graphical Abstract