SNX10 mutations define a subgroup of human Autosomal Recessive Osteopetrosis with variable clinical severity.

• Human Autosomal Recessive Osteopetrosis (ARO) is a genetically heterogeneous disorder caused by reduced bone resorption by osteoclasts. In 2000, we found that mutations in TCIRG1 gene encoding for a subunit of the proton pump (V-ATPase) are responsible for more than half of ARO cases. Afterwards, five additional genes have been demonstrated to be involved in the pathogenesis of the disease, leaving approximately 25% of cases that could not be associated with a genotype. Very recently, a mutation in the Sorting Nexin 10 (SNX10) gene, whose product is suggested to interact with the proton pump, has been found in three consanguineous families of Palestinian origin, thus adding a new candidate gene in patients not previously classified. Here we report the identification of 9 novel mutations in this gene in 14 ARO patients from 12 unrelated families of different geographic origin. Interestingly, we define the molecular defect in 3 cases of "Västerbottenian osteopetrosis", named for the Swedish Province where a higher incidence of the disease has been reported. In our cohort of more than 310 patients from all over the world, SNX10-dependent ARO constitutes 4% of the cases, with a frequency comparable to the RANKL, RANK and OSTM1-dependent subsets. Although the clinical presentation is relatively variable in severity, bone seems to be the only affected tissue and the defect can be almost completely rescued by Hematopoietic Stem Cell Transplantation (HSCT). These results confirm the involvement of SNX10 gene in human ARO and identify a new subset with a relatively favorable prognosis as compared to TCIRG1-dependent cases. Further analyses will help to better understand SNX10 role in osteoclast physiology and verify whether this protein might be considered a new target for selective anti-resorptive therapies. © 2012 American Society for Bone and Mineral Research.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Pediatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Pediatrics (hsv//eng)

Nyckelord

osteopetrosis

SNX10

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