Predominance of a maternal history of diabetes for patients with non-insulin-dependent diabetes mellitus. Implications for the intrauterine transmission of diabetes

Maternal vs paternal diabetes: The parental history is different in younger onset versus older onset type 2 diabetes

BACKGROUND

A number of previous studies exploring family history of type 2 diabetes have reported a predominance of maternal diabetes. These studies have not explicitly compared parental history of diabetes across the spectrum of disease onset from youth to later adulthood.

METHODS

Family history data from 11,467 patients with type 2 diabetes were extracted from the RPA Diabetes Centre database. Parental histories of diabetes were compared across a range of age of diagnosis strata (15-<30, 30-<40, 40-<50, 50-<60 and 60-<70 years). For the young-onset group (diagnosed between 15 and 30 years of age), associations between parental history of diabetes and the presence of cardio-metabolic risk factors and diabetic complications were also explored.

RESULTS

For the total cohort and within each age of diagnosis strata, more individuals reported maternal history than paternal history of diabetes. The young-onset group demonstrated the highest prevalence of any parental history of diabetes (60.7%), the highest combined maternal and paternal history (15.8%) and the smallest differential between maternal (25.1%) and paternal (19.7%) history of diabetes. Within the young-onset group, no significant association between parental history and cardio-metabolic risk factors or diabetic complications were identified after a median of 15.0 years of diabetes exposure.

CONCLUSION

Overall, our results demonstrate a consistent maternal excess of diabetes which could be consistent with an underlying epigenetic effect. However, the differential between maternal and paternal history is significantly lower in the young-onset group. Earlier emergence of type 2 diabetes may therefore reflect a different interaction and impact of genetic and environmental factors.

Prion-Like Protein Aggregates and Type 2 Diabetes

Type 2 diabetes (T2D) is a highly prevalent metabolic disease characterized by chronic insulin resistance and β-cell dysfunction and loss, leading to impaired insulin release and hyperglycemia. Although the mechanism responsible for β-cell dysfunction and death is not completely understood, recent findings suggest that the accumulation of misfolded aggregates of the islet amyloid polypeptide (IAPP) in the islets of Langerhans may play an important role in pancreatic damage. Misfolding and aggregation of diverse proteins and their accumulation as amyloid in different organs is the hallmark feature in a group of chronic, degenerative diseases termed protein misfolding disorders (PMDs). PMDs include highly prevalent human illnesses such as Alzheimer's and Parkinson's disease, as well as more than 25 rarer disorders. Among them, prion diseases are unique because the pathology can be transmitted by a proteinaceous infectious agent, termed a prion, which induces disease by propagating protein misfolding and aggregation. This phenomenon has a striking resemblance to the process of protein misfolding and aggregation in all of the PMDs, suggesting that misfolded aggregates have an intrinsic potential to be transmissible. Indeed, recent studies have shown that the pathological hallmarks of various PMDs can be induced in vivo under experimental conditions by inoculating tissue extracts containing protein aggregates into animal models. In this review, we describe our current understanding of the molecular mechanism underlying the prion-like transmission of protein aggregates and its possible role in T2D.

Excessive maternal transmission of diabetes in Japanese families with young-onset type 2 diabetes and insulin secretion defect according to clinical features

The aim of the study is to identify the clinical characteristics of Japanese patients with young-onset type 2 diabetes (YT2D). Family history of diabetes and clinical data were collected for 30 unrelated males (from 11 to 20 years old at age of onset) and 20 females (from 10 to 20 years old at age of onset) with YT2D diagnosed at ≤ 20 years of age. Fasting C-peptide levels were measured in all, and glucagon stimulation tests were performed twice in six of them over several years. Moreover, 858 people with type 2 diabetes (T2D) diagnosed at >20 years of age were randomly recruited in order to compare the transmission pattern of them. Among the study subjects, 68% reported at least one parent with diabetes. Diabetes was more frequent among mothers than fathers of probands (P = 0.020), although this tendency was not observed in T2D diagnosed at >20 years of age. Fasting C-peptide levels of patients with diabetes duration of ≥ 10 years were significantly lower than for patients with diabetes duration of <10 years (0.61 ± 0.26 vs. 0.84 ± 0.43 nmol/l, P = 0.036). The fasting C-peptide levels among male patients with a family history of diabetes were also significantly lower than those without a family history (0.56 ± 0.25 vs. 0.83 ± 0.37 nmol/l, P = 0.034), while all female subjects had a family history of diabetes. Glucagon stimulation tests showed the following data; 0 min: 0.56 ± 0.31 vs. 0.39 ± 0.22 nmol/l, 3 min: 1.41 ± 0.77 vs. 0.87 ± 0.47 nmol/l, 6 min: 1.37 ± 0.80 vs. 0.79 ± 0.35 nmol/l, 10 min: 1.06 ± 0.60 vs. 0.81 ± 0.49 nmol/l, and 30 min: 0.58 ± 0.30 vs. 0.50 ± 0.19 nmol/l, respectively. These results demonstrated that YT2D among Japanese people occurring in excess with maternal transmission is associated with β-cell dysfunction at the onset of diabetes and as the disease advances.

Familial clustering of type 2 diabetes in Korean women with gestational diabetes mellitus

BACKGROUND/AIMS

This study was conducted to examine the relationship between family history of type 2 diabetes (T2DM) and risk of developing gestational diabetes mellitus (GDM) in Korean women.

METHODS

We performed a 100-g oral glucose tolerance test in 858 pregnant women who had abnormal glucose tolerance in 50-g oral glucose challenge. In addition, we reviewed the incidence of T2DM in the parents and siblings and analyzed the association between the familial history of T2DM and the risk of GDM.

RESULTS

Of the 858 subjects, 427 were normal, and 431 were diagnosed with GDM. Compared with women with no family history of T2DM, women with first degree family history of T2DM displayed higher risk of T2DM (odd ratio: parent only 1.91, sibling only 6.24, any 2.27).

CONCLUSIONS

The risk of developing GDM was significantly increased in Korean women with a family history of T2DM in first-degree relatives.

Familial aggregation and excess maternal transmission of type 2 diabetes in Tunisia

AIM

To evaluate the degree of familial aggregation of type 2 diabetes mellitus in Tunisia and to investigate transmission patterns of the disease and their relationships with patients' clinical profiles.

METHODS

Family history of diabetes and clinical data were collected for 132 unrelated type 2 diabetic Tunisian patients. Diabetes status was recorded for first degree relatives (parents, siblings) and second degree relatives (aunts and uncles from both maternal and paternal sides). Information about family history of diabetes was gathered for a total of 1767 individuals.

RESULTS

Familial aggregation of type 2 diabetes was prominent and more important among first degree relatives than among second degree relatives (p = 0.01). Among studied subjects, 70% reported at least one relative with diabetes and 34% had at least one parent with diabetes. Diabetes was more frequent among mothers than fathers of probands (p = 0.03). This maternal effect extends to second degree relatives as diabetes was more common among maternal than paternal aunts and uncles (p = 0.01). There is no significant difference in clinical and metabolic profiles between patients according to transmission patterns of the disease.

CONCLUSION

These results suggest familial aggregation and excess maternal transmission of type 2 diabetes in the Tunisian studied population.

Mother to child transmission of diabetes mellitus: does gestational diabetes program Type 2 diabetes in the next generation?

AIM

Type 2 diabetes is frequently familial. Hyperglycaemia in pregnancy might act in addition to genetic factors to cause diabetes in the children of mothers with gestational diabetes mellitus (GDM). The first manifestation of this in female offspring is likely to be GDM in their own pregnancies. We compared the incidence of GDM in daughters of diabetic mothers and diabetic fathers to determine if in utero exposure to hyperglycaemia increased the risk of a diabetes-prone phenotype in offspring.

METHODS

We analysed the outcome of a GDM screening programme in women with a family history of diabetes in their mother (n = 535), father (n = 566), both parents (n = 77) or neither (n = 4672).

RESULTS

GDM was twice as common in the daughters of diabetic mothers (11%) than diabetic fathers (5%, P = 0.002). Women with two diabetic parents were no more likely to have GDM than women with only a diabetic mother.

CONCLUSIONS

Genetic predisposition to GDM should be equally shared by daughters of diabetic mothers and fathers. An excess of maternal transmission of diabetes is consistent with an epigenetic effect of hyperglycaemia in pregnancy acting in addition to genetic factors to produce diabetes in the next generation.

Influence of a familial history of diabetes on the clinical characteristics of patients with Type 2 diabetes mellitus

AIMS

To evaluate the roles of maternal and paternal diabetes and diabetes in relatives other than parents on the clinical characteristics in Type 2 diabetes mellitus.

METHODS

A total of 2,113 Type 2 diabetic patients were recruited, and those with diabetic mothers, diabetic fathers, diabetic relatives other than parents and no known diabetic relatives, were considered separately.

RESULTS

The prevalence of diabetes in the mother, father and other relatives was 25.5, 6.5 and 21.2%, respectively. No difference in the clinical characteristics was found in patients with diabetes in the mother or father. Patients with parental diabetes were significantly younger, with higher LDL-cholesterol, prevalence of retinopathy and lower age at diabetes diagnosis than those without familial diabetes; on multiple logistic regression, only age (P = 0.0003), age at diabetes diagnosis (P = 0.0014) (inverse association), and LDL-cholesterol (P = 0.030) remained significantly associated with parental diabetes. Patients with diabetic relatives other than parents displayed significantly higher total and LDL-cholesterol, prevalence of retinopathy and lower age at diabetes diagnosis that those with no known diabetic relatives; on multiple logistic regression, only age at diabetes diagnosis was inversely associated with diabetes in relatives other than parents (P = 0.013).

CONCLUSIONS

The data do not indicate a different influence of maternal and paternal diabetes on the clinical characteristics of Type 2 diabetic patients, while there is evidence that parental diabetes brings to an earlier onset of the disease and higher LDL-cholesterol values; the presence of diabetes in relatives other than parents constituted a small risk for earlier manifestation of the disease.

Mitochondrial DNA A3243G mutation in patients with early- or late-onset type 2 diabetes mellitus in Hong Kong Chinese

BACKGROUND AND OBJECTIVES

The mitochondrial DNA A to G mutation at nucleotide 3243 (mt3243) is associated with a subtype of diabetes characterized by maternal transmission and deafness. We have previously reported a 2.7% prevalence of this mutation in a cohort of young patients with either type 1 or type 2 diabetes. In this study, we aimed to confirm this finding by examining for the prevalence of this mutation in a large-scale study.

SUBJECTS AND METHODS

Nine hundred and six unrelated Chinese patients with type 2 diabetes and 213 nondiabetic controls were studied. The presence of mt3243 mutation was determined by polymerase chain reaction amplification and ApaI digestion.

RESULTS

This mutation was found in four of 133 (3.0%) patients with early onset (</= 40 years) diabetes who also had a positive maternal family history, and in one of 348 (0.3%) patients with late-onset (> 40 years) diabetes and no family history. Basal pancreatic beta-cell function, as assessed by fasting plasma C-peptide, was variable amongst mutation carriers, and did not correlate with the level of heteroplasmy of mutation.

CONCLUSIONS

In agreement with most studies, our results suggest that despite the high prevalence of positive maternal family history of diabetes amongst our type 2 diabetic patients, mt3243 mutation was not a major cause of diabetes in either early- or late-onset diabetic patients in Hong Kong. The role of other genetic, environmental and intrauterine factors needs further investigation.