Two novel nonsense mutations in GALNT3 gene are responsible for familial tumoral calcinosis

Anna Maria Barbieri, Marcello Filopanti, Guido Bua, Paolo Beck-Peccoz

Research output: Contribution to journalArticlepeer-review


Ectopic periarticular calcifications associated with elevated levels of serum phosphate represent the principal clinical features of hyperphosphatemic familial tumoral calcinosis (HFTC), a rare autosomal recessive metabolic disorder. The disease can be caused by recessive mutations in at least two different genes: GalNAc transferase 3 (GALNT3), encoding a glycosyltransferase that initiates mucin-type O-glycosylation, and fibroblast growth factor 23 (FGF23), which encodes a regulator of phosphate circulating levels. In the current study, we performed mutation analyses of the GALNT3 gene in a subject with HFTC and in his relatives. Sequence analyses revealed that the proband was a compound heterozygote for two novel nonsense mutations in exon 4 (Y322X) and in exon 7 (Q481X). Cosegregation of the mutations with the disease within the family was confirmed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. This is the first report describing the simultaneous presence of two different stop codons in the coding sequence of the GALNT3 gene.

Original languageEnglish
Pages (from-to)464-468
Number of pages5
JournalJournal of Human Genetics
Issue number5
Publication statusPublished - May 2007


  • Calcinosis
  • FGF23
  • GALNT3
  • Mutation
  • Phosphate

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics


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