SummaryMitochondrial DNA is exclusively maternally inherited. We recently found the prevalence of diabetic patients with an A to G transition at position 3243 of leucine tRNA (3243 base pair (bp) mutation) to be nearly 1% in randomly selected Japanese subjects. Here, we report the higher prevalence of diabetic patients with the 3243 bp mutation in a specific Japanese population of women attending a diabetic pregnancy clinic. Of 102 patients with non-insulin-dependent diabetes mellitus 6 (5.9 %) were positive for the mutation, 1 (8.3 %) of 12 patients with gestational diabetes and 2 (5.9 %) out of 34 borderline diabetic patients. In contrast, none of 64 patients (0 %) with insulin-dependent diabetes mellitus had the 3243 bp mutation. Moreover, there was a difference in the prevalence of spontaneous abortions between patients with and without this mutation (27.3 vs 12.4%). Among nine probands with the mutation, four had a history of one spontaneous abortion (p = 0.0518) and two had a history of two abortions (p = 0.0479). Two probands had a spontaneous abortion even while under strict diabetic metabolic control. The 3243 bp mutation thus may cause spontaneous abortion during pregnancy. [Diabetologia (1995) 38: 809-815] Key words Mitochondrial DNA mutation, insulin-dependent diabetes mellitus, non-insulin-dependent diabetes mellitus, gestational diabetes mellitus.It is well-known that one of the main causes of spontaneous abortion is an abnormality in the fetus rather than a problem in the mother [1]. The prevalence of abortion in diabetic women is higher in the high-titre HbAI: group during the first trimester [2,3]. Pre-pregnancy education courses are available in diabetic pregnancy clinics in Japan, and diabetic mothers are instructed to keep postprandial blood
A 75-g oral glucose tolerance test (OGTT) was performed in 615 nonobese pregnant women (mean +/- SD age 29.7 +/- 4.3 yr) who were referred to the Division of Internal Medicine at our diabetes center because of glycosuria. Seventy-seven cases were found to have urinary glucose at the first trimester, 185 at the second trimester, and 353 at the third trimester. With their 75-g OGTT results, the diagnostic criteria of borderline (formulated by the Japan Diabetes Society), impaired glucose tolerance (IGT; defined by the World Health Organization [WHO]), and gestational diabetes mellitus (GDM; determined by the Japan Society of Obstetrics& Gynecology standards) were compared through blood glucose (BG) curves and immunoreactive insulin (IRI) responses. Borderline (fasting BG greater than or equal to 6.1 and less than 7.8 mM and 2-h BG greater than or equal to 6.7 and less than 11.1 mM) is neither diabetes nor normal. IGT is as referred to by the WHO. GDM exceeds two points of fasting BG greater than or equal to 5.6 mM, 1-h BG greater than or equal to 10.0 mM, or 2-h BG greater than or equal to 8.3 mM. Diabetes mellitus (DM) is as referred to by the Japan Diabetes Society (same as the WHO). The prevalence of abnormal glucose tolerance among all 615 pregnant women was 54.6% in borderline, 24.5% in IGT, 7.3% in GDM, and 3.4% in DM. The 2-h BG levels in IGT during the first trimester were higher than in borderline (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
It has been well known that there is a high incidence of congenital malformations in newborns from diabetic mothers when the mothers' diabetes control before and during pregnancy is poor. We treated 438 pregnant diabetics who bore 443 children between February 1964 and June 1992. Among these children, there were 51 cases (11.5%) with congenital malformations, 21 cases with major anomalies (4.7%) and 30 cases with minor anomalies (6.8%).
The type of malformations are not related to special organs; heart malformations and cleft lips are relatively frequent compared to other types of malformations. The mechanism of the congenital malformations in newborns from diabetic mothers remains unclear. However, clinically and experimentally it has been found to be due to fuel‐mediated teratogenesis. Since October 1978, HbAi has been used as an index of diabetic control and the relationship between congenital malformations and the mother's diabetes control has been observed. 1) There is no difference in the incidence of malformations in children from IDDM and NIDDM mothers. However, there are more severe malformations in the children from IDDM mothers compared to those from NIDDM mothers. 2) Mothers who bore children with major malformations had all made their first visit to our hospital after pregnancy. HbAi in the IDDM mothers who had children with malformations at the first visit was 11%. 3) In the NIDDM mothers, even if HbAi levels are near normal, children with major malformations were born and there was little relationship between congenital malformations and the mothers' diabetes control.
These data suggest that there are two kinds of congenital malformations in children from diabetic mothers, fuel‐mediated teratogenesis, and malformations as seen in children from non‐diabetic mothers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.