Facioscapulohumeral muscular dystrophy with EcoRI/BlnI fragment size of more than 32 kb.
Facioscapulohumeral muscular dystrophy (FSHD) is associated with the deletion of a variable number of 3.3-kb subunits of a tandemly arranged repeat (D4Z4) on chromosome 4q35. EcoRI/BlnI fragments in the range of 10-35 kb are currently defined as disease-associated. Diagnosis of FSHD is frequently complicated by interchromosomal exchange with a homologous locus on 10q26. We present clinical and laboratory data of six subjects from two unrelated families with a marked FSHD phenotype and EcoRI/BlnI fragments of 39 and 33 kb, respectively. Origin on chromosome 4q35 was confirmed by haplotype analysis in the first family and was supported by pulsed field gel electrophoresis data in the second family. Our data further confirm the existence of a region of overlap of normal and pathological fragments. Fragments from this region can obviously be associated with marked FSHD phenotypes. Furthermore, application of linked markers and resolution of all EcoRI/BlnI fragments by pulsed field gel electrophoresis in addition to routine laboratory tests considerably augments the information obtained from molecular tests, upon which genetic counselling can then be based.
Vielhaber
Stefan
S
Department of Neurology, Otto-von-Guericke University Magdeburg, Medical Center, Leipziger Strasse 44, D-39120 Magdeburg, Germany. stefan.vielhaber@medizin.uni-madgeburg.de
Jakubiczka
Sibylle
S
Schröder
J Michael
JM
Sailer
Michael
M
Feistner
Helmut
H
Heinze
Hans-Jochen
HJ
Wieacker
Peter
P
Bettecken
Thomas
T
D000328:Adult; D000368:Aged; D001483:Base Sequence / Q000235:genetics; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics*; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D053938:DNA Fragmentation / Q000235:genetics*; D004252:DNA Mutational Analysis; D015246:Deoxyribonuclease EcoRI / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D005820:Genetic Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D011995:Recombination, Genetic / Q000235:genetics*
D015246:Deoxyribonuclease EcoRI; C064053:CCTAGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific