[Molecular diagnosis of spinal muscular atrophy by multiplex ligation-dependent probe amplification].
OBJECTIVE
To investigate the effect of multiplex ligation-dependent probe amplification (MLPA) in molecular diagnosis of spinal muscular atrophy (SMA).


METHODS
Peripheral blood samples were collected from 13 SMA patients, 31 parents of SMA patients, 50 healthy individuals without family history of SMA, and 10 specimens of amniotic fluid from these families were collected too. Genomic DNA was analyzed by MLPA, conventional PCR-RFLP, and allele-specific PCR.


RESULTS
In complete agreement with the results of conventional PCR-RFLP and allele-specific PCR, MLPA analysis showed that all of the 13 patients had homozygous deletion of the survival of motor neuron 1 (SMN1) gene, and there was significant difference between the SMA severity (type I to type III) and SMN2 copy number (P < 0.05). Of the 31 parents 29 (93.5%) had 1 copy of SMN1, 2 (6.5%) had 2 copies of SMN1. Of the 50 healthy individuals, 1 (2.0%) had 1 copy of SMN1, 48 (96.0%) had 2 copies of SMN1, and 1 (2.0%) had 3 copies. The SMN1 copy number of the parents was significantly higher than that of the healthy individuals (P < 0.01). Two of the 10 fetuses had homozygous deletion of SMN1.


CONCLUSIONS
The MLPA technique has proved to be an accurate and reliable tool for the molecular diagnosis of SMA, both in patients and in healthy carriers.
Zeng
Jian
J
Research Center for Molecular Diagnosis of Genetic Diseases, Fuzhou General Hospital, Nanjing Military Command, Fuzhou 350025, China.
Ke
Long-feng
LF
Deng
Xiao-jun
XJ
Cai
Mei-ying
MY
Tu
Xiang-dong
XD
Lan
Feng-hua
FH
D000483:Alleles; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D015342:DNA Probes; D005220:Fathers; D005260:Female; D018628:Gene Dosage; D005838:Genotype; D006801:Humans; D008297:Male; D009035:Mothers; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D055532:SMN Complex Proteins / Q000235:genetics; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis* / Q000235:genetics*; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics; D055540:Survival of Motor Neuron 2 Protein
D015342:DNA Probes; D055532:SMN Complex Proteins; C526471:SMN1 protein, human; C526477:SMN2 protein, human; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein