Correlative MR imaging and 31P-MR spectroscopy study in sarcoglycan deficient limb girdle muscular dystrophy.
We combined magnetic resonance (MR) imaging and phosphorus magnetic resonance spectroscopy (31P-MRS) to study skeletal muscle in seven patients with limb girdle muscular dystrophy (LGMD) with a variable deficiency of the alpha-, beta-, and gamma-sarcoglycan but normal dystrophin expression on muscle biopsy. T1- and T2-weighted spin-echo axial leg images showed the highest degree of fat replacement in soleus, tibialis anterior and peroneal muscles while gastrocnemius and tibialis posterior were less affected. In LGMD patients as a group, calf muscle phosphorylated compound content did not differ from controls, but the cytosolic pH was increased (P = 0.02). The degree of calf muscle fat replacement correlated inversely with cytosolic pH (r = 0.74) and directly with PCr/ATP (r = 0.74). Muscle oxidative metabolism was normal in LGMD patients. Our findings show that primary deficits of sarcoglycan complex lead to specific morphological and metabolic patterns of skeletal muscle involvement.
Lodi
R
R
Magnetic Resonance Unit, Oxford Radcliffe Hospital, UK. ral@bioch.ox.ac.uk
Muntoni
F
F
Taylor
J
J
Kumar
S
S
Sewry
C A
CA
Blamire
A
A
Styles
P
P
Taylor
D J
DJ
D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008562:Membrane Glycoproteins / Q000172:deficiency*; D018482:Muscle, Skeletal / Q000378:metabolism; D009136:Muscular Dystrophies / Q000175:diagnosis* / Q000378:metabolism; D010084:Oxidation-Reduction; D010758:Phosphorus
D008562:Membrane Glycoproteins; D010758:Phosphorus