Duchenne muscular dystrophy: a clinical, histopathological and genetic study at a neurology tertiary care center in Southern India.
BACKGROUND
Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy that affects young boys and the dystrophin gene on the X chromosome has been found to be associated with the disorder.


METHODS
In this prospective study, 112 clinically diagnosed DMD patients had muscle biopsy and were tested for exon deletions. Genotyping was also carried out at STR44, STR45, STR49 and STR 50 markers in 15 families.


RESULTS
Of the 112 clinically suspected DMD patients, the diagnosis of DMD was confirmed by histopathology and/or genetics in 101 patients. The mean age of onset was 3.1+/-1.44 years (1-6 years) and the mean age at presentation was 8.0+/-3.1 years (1.1-18.0 years). Delayed motor milestones were present in 63 (62.3%) patients. The mean creatine kinase value was 11822.64+/-8206.90 U/L (1240-57,700). Eighty-four patients had muscle biopsy and immunohistochemistry was done in 60 muscle samples, all of which demonstrated absence of dystrophin staining. Of the 60 dystrophin-negative cases, 73% showed deletion of at least one exon. Single exon deletion was found in 20.4%. Distal hotspot Exons 45, 47, 49 and 50 were the commonly deleted xenons and the deletion rates were 36%, 35%, 33.7% and 38.5% respectively.


CONCLUSIONS
In this study population in south India the deletion rate was 73% and were more frequent in the distal end exon. With the availability of genetic analysis, the first investigation of choice in DMD should be genetic studies and muscle biopsy should be considered only if the genetic tests are negative or not available.
Swaminathan
Bhairavi
B
Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India.
Shubha
G N
GN
Shubha
D
D
Murthy
A Ram
AR
Kiran Kumar
H B
HB
Shylashree
S
S
Gayathri
N
N
Jamuna
R
R
Jain
Sanjeev
S
Purushottam
Meera
M
Nalini
A
A
D002648:Child; D003402:Creatine Kinase / Q000097:blood; D004252:DNA Mutational Analysis; D016189:Dystrophin / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics; D005192:Family Health; D005260:Female; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D009034:Mother-Child Relations; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000097:blood / Q000235:genetics* / Q000473:pathology*; D011446:Prospective Studies; D049031:Sarcoglycans / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics*
D016189:Dystrophin; C526571:SGCA protein, human; D049031:Sarcoglycans; D003402:Creatine Kinase