Early-onset facioscapulohumeral muscular dystrophy type 1 with some atypical features.
Facioscapulohumeral muscular dystrophy cases with facial weakness before the age of 5 and signs of shoulder weakness by the age of 10 are defined as early onset. Contraction of the D4Z4 repeat on chromosome 4q35 is causally related to facioscapulohumeral muscular dystrophy type 1, and the residual size of the D4Z4 repeat shows a roughly inverse correlation with the severity of the disease. Contraction of the D4Z4 repeat on chromosome 4q35 is believed to induce a local change in chromatin structure and consequent transcriptional deregulation of 4qter genes. We present early-onset cases in the Polish population that amounted to 21% of our total population with facioscapulohumeral muscular dystrophy. More than 27% of them presented with severe phenotypes (wheelchair dependency). The residual D4Z4 repeat sizes ranged from 1 to 4 units. In addition, even within early-onset facioscapulohumeral muscular dystrophy type 1 phenotypes, some cases had uncommon features (head drop, early disabling contractures, progressive ptosis, and respiratory insufficiency and cardiomyopathy).
Department of Neurology, Central Clinical Hospital of the Ministry of Interior, Warsaw, Poland Neuromuscular Unit, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Małgorzata
M
Dorobek
Leiden University Medical Center, Center for Human and Clinical Genetics, Leiden, the Netherlands.
Silvère M
SM
van der Maarel
Leiden University Medical Center, Center for Human and Clinical Genetics, Leiden, the Netherlands.
Richard J L F
RJ
Lemmers
Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
Barbara
B
Ryniewicz
Neuromuscular Unit, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Dagmara
D
Kabzińska
Leiden University Medical Center, Center for Human and Clinical Genetics, Leiden, the Netherlands.
Rune R
RR
Frants
Department of Neurology, Medical University of Warsaw, Warsaw, Poland mgawel@wum.edu.pl.
Malgorzata
M
Gawel
Department of Radiology, Central Clinical Hospital of the Ministry of Interior, Warsaw, Poland.
Jerzy
J
Walecki
Neuromuscular Unit, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Irena
I
Hausmanowa-Petrusewicz
D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D002894:Chromosomes, Human, Pair 4; D004252:DNA Mutational Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000473:pathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009132:Muscles / Q000473:pathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D010641:Phenotype; D011044:Poland; D012091:Repetitive Sequences, Nucleic Acid; D012720:Severity of Illness Index; D014910:Wheelchairs
4q35 deletion; early-onset facioscapulohumeral muscular dystrophy; infantile facioscapulohumeral muscular dystrophy