Homozygous myotonic dystrophy with craniosynostosis.
Myotonic dystrophy is considered a true dominant condition with no difference in the phenotype between heterozygous and homozygous cases. The homozygous state is very rare and only a few patients have been reported in the literature. We report a 2.5-year-old boy from a nonconsanguineous marriage, with a unique combination of clinical and radiological findings: hypotonia, motor and language developmental delay, ventriculomegaly, subcortical white matter lesions, and craniosynostosis. Mutation analysis revealed 2 copies of expansion mutation of 1260 and 60 cytosine-thymine-guanine repeats in the myotonic dystrophy protein kinase gene. Both the mildly symptomatic (434 repeats) mother and the asymptomatic (37 repeats) father are heterozygous. Craniosynostosis has not been reported previously in myotonic dystrophy. This homozygous case expands the clinical spectrum of myotonic dystrophy type 1 and provides support to the hypothesis that myotonic dystrophy type 1 pathophysiology could be, in part, due to the loss of normal function of the wild-type protein.
Cerghet
Mirela
M
Department of Pediatrics, Wayne State University, Detroit, Michigan 48201 USA.
Tapos
Daniela
D
Serajee
Fatema J
FJ
Mahbubul Huq
A H M
AH
D000483:Alleles; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002675:Child, Preschool; D003393:Cranial Sutures / Q000000981:diagnostic imaging; D003398:Craniosynostoses / Q000175:diagnosis / Q000235:genetics*; D003596:Cytosine / Q000378:metabolism; D004252:DNA Mutational Analysis; D042622:DNA Repeat Expansion / Q000235:genetics; D006147:Guanine / Q000378:metabolism; D006720:Homozygote; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007805:Language Development Disorders / Q000175:diagnosis / Q000235:genetics; D008297:Male; D009223:Myotonic Dystrophy / Q000175:diagnosis / Q000235:genetics*; D065636:Myotonin-Protein Kinase; D009460:Neurologic Examination; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D011859:Radiography; D012886:Skull / Q000000981:diagnostic imaging; D013941:Thymine / Q000378:metabolism
C585517:DMPK protein, human; D006147:Guanine; D003596:Cytosine; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases; D013941:Thymine