Update on Monogenic Diabetes in Korea

Identification of rare variants in candidate genes associated with monogenic diabetes in polish mody-x patients

Purpose

Monogenic diabetes (MD) is caused by a mutation in a single gene and accounts for approximately 2.5-6% of all diabetes cases. Maturity-onset diabetes of the young (MODY) is the most common form of MD. To date, 14 different genes have been identified and associated with the presence of MODY phenotype. However, the number of potential candidate genes with relevance to beta cell function and glucose metabolism is increasing as more research is published. The aim of the study was to identify potentially causative variants in selected candidate genes in patients with a clinical diagnosis of MD.

Methods

Targeted Next-Generation Sequencing (tNGS) on Illumina NextSeq 550 platform involving Agilent SureSelectQXT Target Enrichment protocol for 994 patients with suspected MD was performed. In the next step, the sequencing data of 617 patients with no pathogenic variants in main MD-related genes were reanalysed for the presence of causative variants in six candidate genes (MTOR, TBC1D4, CACNA1E, MNX1, SLC19A2, KCNH6). The presence of the selected variants was confirmed by Sanger sequencing.

Results

Seven heterozygous possibly damaging variants were identified in four candidate genes (MTOR, TBC1D4, CACNA1E, MNX1). Five changes were assessed as novel variants, not previously described in available databases. None of the described variants were present among patients previously diagnosed with MODY diabetes due to causative, pathogenic variants in known MODY-related genes.

Conclusions

The results obtained seem to confirm the effectiveness of the NGS method in identifying potentially causative variants in novel candidate genes associated with MODY diabetes.

Genetic perspectives on childhood monogenic diabetes: Diagnosis, management, and future directions

Monogenic diabetes is caused by one or even more genetic variations, which may be uncommon yet have a significant influence and cause diabetes at an early age. Monogenic diabetes affects 1 to 5% of children, and early detection and gene-tically focused treatment of neonatal diabetes and maturity-onset diabetes of the young can significantly improve long-term health and well-being. The etiology of monogenic diabetes in childhood is primarily attributed to genetic variations affecting the regulatory genes responsible for beta-cell activity. In rare instances, mutations leading to severe insulin resistance can also result in the development of diabetes. Individuals diagnosed with specific types of monogenic diabetes, which are commonly found, can transition from insulin therapy to sulfonylureas, provided they maintain consistent regulation of their blood glucose levels. Scientists have successfully devised materials and methodologies to distinguish individuals with type 1 or 2 diabetes from those more prone to monogenic diabetes. Genetic screening with appropriate findings and interpretations is essential to establish a prognosis and to guide the choice of therapies and management of these interrelated ailments. This review aims to design a comprehensive literature summarizing genetic insights into monogenetic diabetes in children and adolescents as well as summarizing their diagnosis and mana-gement.

Efficacy of acupuncture on cardiovascular complications in patients with diabetes mellitus in Korea: A nationwide retrospective cohort

OBJECTIVE

The main aim of this study is to investigate whether acupuncture could be an effective complementary treatment for reducing the risk of macrovascular complications in diabetic patients currently taking antidiabetic medications using a nationwide population-based database.

METHODS

We conducted a retrospective cohort study to assess the efficacy of acupuncture on cardiovascular complications in diabetic patients using data from patients between 40 and 79 years of age, newly diagnosed with diabetes between 2003 and 2006, found in the National Health Insurance Service-National Sample Cohort (NHIS-NSC) in Korea. From the data, we identified 21,232 diabetic patients who were taking antidiabetic medication between 2003 and 2006. The selected patients were divided into two groups-those who received acupuncture at least three times and those who received no acupuncture (non-acupuncture) in the year following their diagnosis of diabetes. After 1:1 propensity score matching (PSM), each group had 3350 patients, and the observation ceased at the occurrence of a major adverse cardiovascular event (MACE), which was defined as either myocardial infarction, stroke, or death due to cardiovascular cause.

RESULTS

After PSM, the acupuncture group had a lower incidence of MACE (hazard ratio [HR]: 0.87; 95% confidence interval [CI]: 0.81-0.94; P = 0.0003) and all-cause mortality (HR: 0.77; 95% CI: 0.70-0.84; P < 0.0001) than the non-acupuncture group; the HRs for stroke-related mortality (HR: 0.75; 95% CI: 0.56-1.00; P = 0.0485), ischemic heart disease mortality (HR: 0.53; 95% CI: 0.34-0.84; P = 0.006) and circulatory system disease mortality (HR: 0.67; 95% CI: 0.55-0.82; P < 0.0001) were lower in the acupuncture group than in the non-acupuncture group in the secondary analysis.

CONCLUSION

Our results indicate that diabetic patients receiving acupuncture treatment might have a lower risk of MACE, all-cause mortality and cardiovascular mortality. This population-based retrospective study suggests beneficial effects of acupuncture in preventing macrovascular complications associated with diabetes. These findings call for further prospective cohort or experimental studies on acupuncture treatment for cardiovascular complications of diabetes. Please cite this article as: Jung H, Won T, Kim GY, Jang J, Yeo S, Lim S. Efficacy of acupuncture on cardiovascular complications in patients with diabetes mellitus in Korea: A nationwide retrospective cohort. J Integr Med. 2023; Epub ahead of print.

The Genetic Spectrum of Maturity-Onset Diabetes of the Young (MODY) in Qatar, a Population-Based Study

Maturity-onset diabetes of the young (MODY) is a rare monogenic form of diabetes mellitus. In this study, we estimated the prevalence and genetic spectrum of MODY in the Middle Eastern population of Qatar using whole-genome sequencing (WGS) of 14,364 subjects from the population-based Qatar biobank (QBB) cohort. We focused our investigations on 14 previously identified genes ascribed to the cause of MODY and two potentially novel MODY-causing genes, RFX6 and NKX6-1. Genetic variations within the 16 MODY-related genes were assessed for their pathogenicity to identify disease-causing mutations. Analysis of QBB phenotype data revealed 72 subjects (0.5%) with type 1 diabetes, 2915 subjects (20.3%) with type 2 diabetes and 11,377 (79.2%) without diabetes. We identified 22 mutations in 67 subjects that were previously reported in the Human Genetic Mutation Database (HGMD) as disease-causing (DM) or likely disease causing (DM?) for MODY. We also identified 28 potentially novel MODY-causing mutations, predicted to be among the top 1% most deleterious mutations in the human genome, which showed complete (100%) disease penetrance in 34 subjects. Overall, we estimated that MODY accounts for around 2.2-3.4% of diabetes patients in Qatar. This is the first population-based study to determine the genetic spectrum and estimate the prevalence of MODY in the Middle East. Further research to characterize the newly identified mutations is warranted.

Targeted gene panel analysis of Japanese patients with maturity-onset diabetes of the young-like diabetes mellitus: Roles of inactivating variants in the ABCC8 and insulin resistance genes

AIMS/INTRODUCTION

To investigate the genetic background of Japanese patients with suspected maturity-onset diabetes of the young (MODY).

MATERIALS AND METHODS

On 340 proband patients referred from across Japan, genomic variants were analyzed using a targeted multigene panel analysis combined with the multiplex ligation probe amplification (MLPA) analysis, mitochondrial m.3243A > G analysis and methylation-specific polymerase chain reaction of the imprinted 6q24 locus. Pathogenic/likely pathogenic variants were listed according to the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology criteria. Additionally, variants with a population frequency <0.001 and Combined Annotation Dependent Depletion score >20 (CS >20) were listed as rare variants of uncertain significance-CS >20.

RESULTS

A total of 157 pathogenic/likely pathogenic variants and 44 rare variants of uncertain significance-CS >20 were identified. In the pathogenic/likely pathogenic variants, alterations in the GCK gene were the most common (82, 52.2%) followed by HNF1A (29, 18.5%), HNF4A (13, 8.3%) and HNF1B (13, 8.3%). One patient was a 29.5% mosaic with a truncating INSR variant. In the rare variants of uncertain significance-CS >20, 20 (45.5%) were in the genes coding for the adenosine triphosphate-sensitive potassium channel, KCNJ11 or ABCC8, and four were in the genes of the insulin-signaling pathway, INSR and PIK3R1. Four variants in ABCC8 were previously reported in patients with congenital hyperinsulinism, suggesting the inactivating nature of these variants, and at least two of our patients had a history of congenital hyperinsulinism evolving into diabetes. In two patients with INSR or PIK3R1 variants, insulin resistance was evident at diagnosis.

CONCLUSIONS

Causative genomic variants could be identified in at least 46.2% of clinically suspected MODY patients. ABCC8-MODY with inactivating variants could represent a distinct category of MODY. Genes of insulin resistance should be included in the sequencing panel for MODY.

Muscle strength, an independent determinant of glycemic control in older adults with long-standing type 2 diabetes: a prospective cohort study

Background

Although the proportion of older patients with type 2 diabetes mellitus (T2DM) has increased, few studies have reported the factors affecting glucose levels in older patients with long-standing T2DM. This study assessed the determinants of glycemic control in older adults with T2DM of a duration of ≥10 years, including muscle mass, muscle quality, and β-cell function.

Methods

This was a prospective study of older patients aged ≥60 years with a T2DM duration of ≥10 years. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index, handgrip strength (HGS), and body composition through bioelectrical impedance analysis were assessed. The primary outcome was a composite of: (i) increment of glycated hemoglobin (HbA1c) from the baseline ≥0.6% and (ii) HbA1c ≥ 9% at any time point during the follow-up period. To find the predicting determinants of the outcome, we performed the Cox proportional hazard analysis.

Results

Among 100 patients (mean age, 64.0 ± 8.6 years; median duration of diabetes, 20 [interquartile range (IQR), 17–23] years; median HbA1c at baseline, 7.1 [IQR, 6.7–7.4] %), the primary outcome was observed in 40 (40.0%) patients during 4.0 (IQR 2.3–5.0) years of follow-up. A Cox proportional hazards model adjusted for age, sex, baseline HbA1c, obesity, duration of DM and anti-diabetic medication at baseline showed that low HGS and insulin resistance at the baseline were independent determinants of the primary outcome (hazard ratio [HR] = 2.23 [95% confidence interval (CI), 1.06–4.72] and 2.39 [95% CI, 1.18–4.83], respectively). Sex stratification confirmed that HGS and muscle mass were independent determinants of the primary outcome only in women (HR per quartile, 0.58 [95% CI, 0.37–0.93] and 0.46 [95% CI, 0.25–0.85], respectively). `.

Conclusions

Low HGS and insulin resistance were independent risk factors for aggravated glycemic control among older patients with long standing T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02629-5.

Sequencing Cell-free Fetal DNA in Pregnant Women With GCK-MODY

CONTEXT

Individuals with monogenic diabetes due to inactivating glucokinase (GCK) variants typically do not require treatment, except potentially during pregnancy. In pregnancy, fetal GCK genotype determines whether treatment is indicated, but noninvasive methods are not clinically available.

OBJECTIVE

This work aims to develop a method to determine fetal GCK genotype noninvasively using maternal cell-free fetal DNA.

METHODS

This was a proof-of-concept study involving 3 pregnant women with a causal GCK variant that used information from 1) massive parallel sequencing of maternal plasma cell-free DNA, 2) direct haplotype sequences of maternal genomic DNA, and 3) the paternal genotypes to estimate relative haplotype dosage of the pathogenic variant-linked haplotype. Statistical testing of variant inheritance was performed using a sequential probability ratio test (SPRT).

RESULTS

In each of the 3 cases, plasma cell-free DNA was extracted once between gestational weeks 24 and 36. The fetal fraction of cell-free DNA ranged from 21.8% to 23.0%. Paternal homozygous alleles that were identical to the maternal GCK variant-linked allele were not overrepresented in the cell-free DNA. Paternal homozygous alleles that were identical to the maternal wild-type-linked allele were significantly overrepresented. Based on the SPRT, we predicted that all 3 cases did not inherit the GCK variant. Postnatal infant genotyping confirmed our prediction in each case.

CONCLUSION

We have successfully implemented a noninvasive method to predict fetal GCK genotype using cell-free DNA in 3 pregnant women carrying an inactivating GCK variant. This method could guide tailoring of hyperglycemia treatment in pregnancies of women with GCK monogenic diabetes.