Skip to main content


Mc Cune Albright syndrome: estimation of bone strength parameters and response to treatment using peripheral Quantitive Computed Tomography (pQCT) of the tibia

Article metrics

  • 727 Accesses


We assessed bone strength parameters and response to treatment in a girl with McCune -Albright syndrome (MAS) using tibia pQCT.


We present a 14y old girl with polyostotic fibrous dysplasia (right humerus, femur, tibia, skull), precocious puberty and café au lait skin spots, diagnosed as MAS with a confirmed heterozygous c.601C>T mutation of the GNAS1 gene. Due to initial bone pain and continuously increasing bone turnover, the patient was treated with iv bisphosphonates for 4 years. We used pQCT to estimate bone strength parameters at the site of fibrous dysplasia lesion of the right tibia (38% of tibia length) vs the same site of the left (healthy) tibia at baseline and after treatment. A Stratec XCT-2000 scanner was used (Stratec Medizintechnik, Pforzheim, Germany) and we specifically assessed for the 38% site cortical BMC (Cort_CNT), cortical BMD (Cort_DEN), cortical area (Cort_A),cortical thickness (Cort_THK) and Stress Strain Index (SSI) as an indicator of bending/torsional strength.


At baseline all parameters were lower at the right (lesional) tibia: Cort_DEN (right 916.53 vs left 1154.47 mg/cm³), Cort_CNT (0.78 vs 2.65 gr/cm), Cort_A (85 vs 230.25 mm2) , Cort_THK ( 0.99 vs 4.76 mm), SSI (941 vs 1110.35 mm3). All parameters increased significantly after 4 years of therapy at both legs with maximal increases at the lesional tibia: Cort_DEN (left +10.16% vs right + 13.54%), Cort CNT (+13.9% vs +34.6%), Cort_A (+3.14% vs +19.7%), Cort_THK (+4.2% vs +19.19%), SSI (+16.77% vs +26.4%).


1) With 3- dimensional densitometry we can actually measure the loss of cortical bone and derived strength of lesional sites in MAS 2) All bone strength parameters improved with iv bisphosphonates. P QCT, where applicable, is an easy, safe and accurate method for non invasive monitoring of disease progress.

Author information

Correspondence to E Atsali.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and Permissions

About this article


  • Fibrous Dysplasia
  • Precocious Puberty
  • Peripheral Quantitative Compute Tomography
  • Polyostotic Fibrous Dysplasia
  • GNAS1 Gene