TY - JOUR
T1 - Is mutated serine hydroxymethyltransferase (SHMT) involved in the etiology of neural tube defects?
AU - Heil, Sandra G.
AU - Van Der Put, Nathalie M.J.
AU - Waas, Erwin T.
AU - Den Heijer, Martin
AU - Trijbels, Frans J.M.
AU - Blom, Henk J.
N1 - Funding Information: The authors thank Addy de Graaf-Hess, Dinny van Oppenraaij-Emmerzaal, Maria Te Poele-Pothoff, and Lydia Afman for their valuable contribution. This study was supported by Grants 93- 1104 and 94-029 from the Princes Beatrix foundation, The Netherlands, and by Grant D97.021 of The Netherlands Heart Foundation.
PY - 2001
Y1 - 2001
N2 - Neural tube defects (NTD) arise in the first weeks of pregnancy due to a combination of environmental and genetic factors. In mothers of children with NTD elevated homocysteine (Hcy) levels and decreased plasma folate levels were observed, which suggests a defect in the folate-dependent Hcy metabolism. Therefore, mutations in genes coding for enzymes of this metabolism could be involved in NTD. Serine hydroxymethyltransferase (SHMT) catalyzes the reversible reaction of serine and tetrahydrofolate (THF) to glycine and 5,10-methylene THF. Two different isoforms of SHMT are known, one is present in the cytosol (cSHMT) and the other in the mitochondrion (mSHMT). Theoretically, mutated SHMT could lead to elevated Hcy levels and to an altered distribution of the different folate derivatives and might therefore become a risk factor for NTD. This study concerns the molecular genetic analysis of genes coding for both isoforms of the SHMT enzyme by single-stranded conformation polymorphism analysis. Several mutations as well as polymorphisms were found in both genes. The relevance of two variations, the 1420 C>T mutation of the cytosolic isoform and the 4-bp deletion of the mitochondrial isoform (delTCTT 1721-1724), to NTD risk was tested in a study group, which consisted of 109 NTD patients, 120 mothers of children with NTD, and 420 controls. Neither of the two polymorphisms led to an increased risk of NTD. In mothers with the 1420 CC genotype, significant increased Hcy levels are present. Also, significantly decreased red blood cell folate and plasma folate levels were present in individuals with the 1420 CC genotype. Probably, the 1420 C>T polymorphism causes a shift in distribution of the different folate derivatives. The 4-bp deletion of the mSHMT gene did not lead to altered Hcy or folate levels. So far, the results of this study provide no direct evidence for a role of defective SHMT functioning in NTD. Still, the influence of the 1420 C>T polymorphism of the cSHMT gene on the folate-orelated risk of NTD needs further investigation.
AB - Neural tube defects (NTD) arise in the first weeks of pregnancy due to a combination of environmental and genetic factors. In mothers of children with NTD elevated homocysteine (Hcy) levels and decreased plasma folate levels were observed, which suggests a defect in the folate-dependent Hcy metabolism. Therefore, mutations in genes coding for enzymes of this metabolism could be involved in NTD. Serine hydroxymethyltransferase (SHMT) catalyzes the reversible reaction of serine and tetrahydrofolate (THF) to glycine and 5,10-methylene THF. Two different isoforms of SHMT are known, one is present in the cytosol (cSHMT) and the other in the mitochondrion (mSHMT). Theoretically, mutated SHMT could lead to elevated Hcy levels and to an altered distribution of the different folate derivatives and might therefore become a risk factor for NTD. This study concerns the molecular genetic analysis of genes coding for both isoforms of the SHMT enzyme by single-stranded conformation polymorphism analysis. Several mutations as well as polymorphisms were found in both genes. The relevance of two variations, the 1420 C>T mutation of the cytosolic isoform and the 4-bp deletion of the mitochondrial isoform (delTCTT 1721-1724), to NTD risk was tested in a study group, which consisted of 109 NTD patients, 120 mothers of children with NTD, and 420 controls. Neither of the two polymorphisms led to an increased risk of NTD. In mothers with the 1420 CC genotype, significant increased Hcy levels are present. Also, significantly decreased red blood cell folate and plasma folate levels were present in individuals with the 1420 CC genotype. Probably, the 1420 C>T polymorphism causes a shift in distribution of the different folate derivatives. The 4-bp deletion of the mSHMT gene did not lead to altered Hcy or folate levels. So far, the results of this study provide no direct evidence for a role of defective SHMT functioning in NTD. Still, the influence of the 1420 C>T polymorphism of the cSHMT gene on the folate-orelated risk of NTD needs further investigation.
KW - Folate
KW - Homocysteine (Hcy)
KW - Mutation
KW - Neural tube defects (NTD)
KW - Plasma folate
KW - RBC folate
KW - SSCP
KW - Serine hydroxymethyltransferase (SHMT)
UR - http://www.scopus.com/inward/record.url?scp=0034968527&partnerID=8YFLogxK
U2 - https://doi.org/10.1006/mgme.2001.3175
DO - https://doi.org/10.1006/mgme.2001.3175
M3 - Article
C2 - 11386852
SN - 1096-7192
VL - 73
SP - 164
EP - 172
JO - Molecular Genetics and Metabolism
JF - Molecular Genetics and Metabolism
IS - 2
ER -