UMMS Affiliation

Department of Quantitative Health Sciences; Department of Molecular Cell and Cancer Biology; Li Weibo Institute for Rare Diseases Research

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Biochemical Phenomena, Metabolism, and Nutrition | Congenital, Hereditary, and Neonatal Diseases and Abnormalities | Diagnosis | Genetics and Genomics | Molecular Biology | Nervous System Diseases


Facioscapulohumeral muscular dystrophy (FSHD) is characterized by incomplete penetrance and intra-familial clinical variability. The disease has been associated with the genetic and epigenetic features of the D4Z4 repetitive elements at 4q35. Recently, D4Z4 hypomethylation has been proposed as a reliable marker in the FSHD diagnosis. We exploited the Italian Registry for FSHD, in which FSHD families are classified using the Clinical Comprehensive Evaluation Form (CCEF). A total of 122 index cases showing a classical FSHD phenotype (CCEF, category A) and 110 relatives were selected to test with the receiver operating characteristic (ROC) curve, the diagnostic and predictive value of D4Z4 methylation. Moreover, we performed DNA methylation analysis in selected large families with reduced penetrance characterized by the co-presence of subjects carriers of one D4Z4 reduced allele with no signs of disease or presenting the classic FSHD clinical phenotype. We observed a wide variability in the D4Z4 methylation levels among index cases revealing no association with clinical manifestation or disease severity. By extending the analysis to family members, we revealed the low predictive value of D4Z4 methylation in detecting the affected condition. In view of the variability in D4Z4 methylation profiles observed in our large cohort, we conclude that D4Z4 methylation does not mirror the clinical expression of FSHD. We recommend that measurement of this epigenetic mark must be interpreted with caution in clinical practice.


D4Z4 reduced allele, DNA methylation, FSHD, genotype–phenotype correlation, molecular diagnosis

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© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (

DOI of Published Version



Nikolic A, Jones TI, Govi M, Mele F, Maranda L, Sera F, Ricci G, Ruggiero L, Vercelli L, Portaro S, Villa L, Fiorillo C, Maggi L, Santoro L, Antonini G, Filosto M, Moggio M, Angelini C, Pegoraro E, Berardinelli A, Maioli MA, D'Angelo G, Di Muzio A, Siciliano G, Tomelleri G, D'Esposito M, Della Ragione F, Brancaccio A, Piras R, Rodolico C, Mongini T, Magdinier F, Salsi V, Jones PL, Tupler R. Interpretation of the Epigenetic Signature of Facioscapulohumeral Muscular Dystrophy in Light of Genotype-Phenotype Studies. Int J Mol Sci. 2020 Apr 10;21(7):2635. doi: 10.3390/ijms21072635. PMID: 32290091; PMCID: PMC7178248. Link to article on publisher's site

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International journal of molecular sciences


Full author list omitted for brevity. For the full list of authors, see article.

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.