Hybridization analysis of D4Z4 repeat arrays linked to FSHD.
Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease involving shortening of D4Z4, an array of tandem 3.3-kb repeat units on chromosome 4. These arrays are in subtelomeric regions of 4q and 10q and have 1-100 units. FSHD is associated with an array of 1-10 units at 4q35. Unambiguous clinical diagnosis of FSHD depends on determining the array length at 4q35, usually with the array-adjacent p13E-11 probe after pulsed-field or linear gel electrophoresis. Complicating factors for molecular diagnosis of FSHD are the phenotypically neutral 10q D4Z4 arrays, cross-hybridizing sequences elsewhere in the genome, deletions including the genomic p13E-11 sequence and part of D4Z4, translocations between 4q and 10q D4Z4 arrays, and the extremely high G + C content of D4Z4 arrays (73%). In this study, we optimized conditions for molecular diagnosis of FSHD with a 1-kb D4Z4 subfragment probe after hybridization with p13E-11. We demonstrate that these hybridization conditions allow the identification of FSHD alleles with deletions of the genomic p13E-11 sequence and aid in determination of the nonpathogenic D4Z4 arrays at 10q. Furthermore, we show that the D4Z4-like sequences present elsewhere in the genome are not tandemly arranged, like those at 4q35 and 10q26.
Ehrlich
Melanie
M
Program in Human Genetics and Department of Biochemistry, Tulane Medical School, New Orleans, LA, USA. ehrlich@tulane.edu
Jackson
Kesmic
K
Tsumagari
Koji
K
Camaño
Pilar
P
Lemmers
Richard J F L
RJ
D000818:Animals; D001483:Base Sequence / Q000235:genetics*; D002460:Cell Line; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D006224:Cricetinae; D003412:Cricetulus; D017931:DNA Primers; D015342:DNA Probes / Q000235:genetics; D004586:Electrophoresis; D040461:Gene Components; D006801:Humans; D015151:Immunoblotting; D025202:Molecular Diagnostic Techniques / Q000379:methods; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000235:genetics*; D009426:Netherlands; D009693:Nucleic Acid Hybridization / Q000379:methods; D017384:Sequence Deletion / Q000235:genetics*; D020080:Tandem Repeat Sequences / Q000235:genetics*
D017931:DNA Primers; D015342:DNA Probes