Prenatal prediction of childhood-onset spinal muscular atrophy (SMA) in Turkish families.
Childhood-onset spinal muscular atrophy (SMA) is one of the most common neurodegenerative genetic disorders. SMN1 is the SMA-determining gene deleted or mutated in the majority of SMA cases. There is no effective cure or treatment for this disease yet. Thus, the availability of prenatal testing is important. Here we report prenatal prediction for 68 fetuses in 63 Turkish SMA families using direct deletion analysis of the SMN1 gene by restriction digestion. The genotype of the index case was known in 40 families (Group A) but unknown in the remaining 23 families (Group B). A total of ten fetuses were predicted to be affected. Eight of these fetuses were derived from Group A and two of these fetuses were from Group B families. Two fetuses from the same family in Group A had the SMNhyb1 gene in addition to homozygous deletion of the NAIP gene. One fetus from Group A was homozygously deleted for only exon 8 of the SMN2 gene, and further analysis showed the presence of both the SMN1 and SMNhyb1 genes but not the SMN2 gene. In addition, one carrier with a homozygous deletion of only exon 8 of the SMN1 gene was detected to have a SMNhyb2 gene, which was also found in the fetus. To our knowledge, these are the first prenatal cases with SMNhyb genes. Follow-up studies demonstrated that the prenatal predictions and the phenotype of the fetuses correlated well in 33 type I pregnancies demonstrating that a careful molecular analysis of the SMN genes is very useful in predicting the phenotype of the fetus in families at risk for SMA.
Savas
S
S
Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey. savas@mshri.on.ca
Eraslan
S
S
Kantarci
S
S
Karaman
B
B
Acarsoz
D
D
Tükel
T
T
Cogulu
O
O
Ozkinay
F
F
Basaran
S
S
Aydinli
K
K
Yuksel-Apak
M
M
Kirdar
B
B
D017362:Cyclic AMP Response Element-Binding Protein; D004262:DNA Restriction Enzymes; D005091:Exons; D005260:Female; D017353:Gene Deletion; D005838:Genotype; D006720:Homozygote; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics*; D051616:Neuronal Apoptosis-Inhibitory Protein; D010641:Phenotype; D011247:Pregnancy; D011296:Prenatal Diagnosis; D016601:RNA-Binding Proteins; D055532:SMN Complex Proteins; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis* / Q000235:genetics*; D055533:Survival of Motor Neuron 1 Protein; D055540:Survival of Motor Neuron 2 Protein; D014421:Turkey
D017362:Cyclic AMP Response Element-Binding Protein; C496800:NAIP protein, human; D009419:Nerve Tissue Proteins; D051616:Neuronal Apoptosis-Inhibitory Protein; D016601:RNA-Binding Proteins; 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; D004262:DNA Restriction Enzymes