Study of gene expression profile in facioscapulohumeral muscular dystrophy (FSHD)

Author(s)

Patricia Arashiro

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2009-03-19

Examining board members

Mayana Zatz; Maria Rita dos Santos e Passos Bueno; Fernando Kok; Helga Cristina Almeida da Silva; Mariz Vainzof

• Advisor: Mayana Zatz

Abstract

FSHD is characterized by a great clinical inter and intrafamilial variability. Approximately 10-20% of patients eventually becoming wheelchair-bound while 20-30% with a shortened D4Z4 array, remains asymptomatic or minimally affected. Interestingly, these cases seem to be concentrated in some particular families, suggesting that some mechanism might be acting in these individuals, protecting them form the effects of the disease. In order to try to explain this clinical variability observed in FSHD, we compared the expression profiles of muscle tissue from three members (affected, asymptomatic carrier and normal control) from five unrelated FSHD families through expression and exon microarrays. Our results suggest that the expression of genes on chromosome 4q is altered in affected and asymptomatic individuals. Remarkably, the changes seen in asymptomatic samples are largely in products of genes encoding several chemokines, whereas the changes seen in affected samples are largely in genes governing the synthesis of GPI-linked proteins and histone acetylation. Besides this, the affected patient and related asymptomatic carrier share the 4qA161 haplotype, thus these polymorphisms by themselves do not explain the pathogenicity of the contracted allele. Together, our results support the previous evidences that FSHD may be caused by transcriptional dysregulation of multiple genes, in cis and in trans, and suggest some factors potentially important for FSHD pathogenesis. The study of gene expression profiles from asymptomatic carriers is a novel approach that is revealing new and interesting results. Understanding such mechanisms is a great challenge, but will certainly lead to the development of new tools for prognosis and also for future treatment. (AU)