Extensive germinal mosaicism in a family with X linked myotubular myopathy simulates genetic heterogeneity.
A family with two male cousins affected with myotubular myopathy (MTM) was referred to us for genetic counselling. Linkage analysis appeared to exclude the Xq28 region. As a gene for X linked MTM was recently identified in Xq28, we screened the obligatory carrier mothers for mutation. We found a 4 bp deletion in exon 4 of the MTM1 gene, which originated from the grandfather of the affected children and which was transmitted to three daughters. This illustrates the importance of mutation detection to avoid pitfalls in linkage analysis that may be caused by such cases of germinal mosaicism.
Vincent
M C
MC
Laboratoire de Génétique Moleculaire Humaine, Faculté de Médecine et CHRU, Illkirch, Strasbourg, France.
Guiraud-Chaumeil
C
C
Laporte
J
J
Manouvrier-Hanu
S
S
Mandel
J L
JL
D004252:DNA Mutational Analysis; D005260:Female; D005817:Genetic Counseling; D018740:Genetic Heterogeneity; D008040:Genetic Linkage; D005820:Genetic Testing; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009030:Mosaicism; D009123:Muscle Hypotonia / Q000235:genetics*; D018908:Muscle Weakness / Q000235:genetics; D010375:Pedigree; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D014960:X Chromosome
D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; C099588:myotubularin