Screening for monogenic diabetes in primary care

Genetically guided precision medicine clinical decision support tools: a systematic review

OBJECTIVES

Patient care using genetics presents complex challenges. Clinical decision support (CDS) tools are a potential solution because they provide patient-specific risk assessments and/or recommendations at the point of care. This systematic review evaluated the literature on CDS systems which have been implemented to support genetically guided precision medicine (GPM).

MATERIALS AND METHODS

A comprehensive search was conducted in MEDLINE and Embase, encompassing January 1, 2011-March 14, 2023. The review included primary English peer-reviewed research articles studying humans, focused on the use of computers to guide clinical decision-making and delivering genetically guided, patient-specific assessments, and/or recommendations to healthcare providers and/or patients.

RESULTS

The search yielded 3832 unique articles. After screening, 41 articles were identified that met the inclusion criteria. Alerts and reminders were the most common form of CDS used. About 27 systems were integrated with the electronic health record; 2 of those used standards-based approaches for genomic data transfer. Three studies used a framework to analyze the implementation strategy.

DISCUSSION

Findings include limited use of standards-based approaches for genomic data transfer, system evaluations that do not employ formal frameworks, and inconsistencies in the methodologies used to assess genetic CDS systems and their impact on patient outcomes.

CONCLUSION

We recommend that future research on CDS system implementation for genetically GPM should focus on implementing more CDS systems, utilization of standards-based approaches, user-centered design, exploration of alternative forms of CDS interventions, and use of formal frameworks to systematically evaluate genetic CDS systems and their effects on patient care.

Cost-effectiveness of genetic-based screening strategies for maturity-onset diabetes of the young

Maturity-onset diabetes of the young (MODY) is often misdiagnosed as Type I or II diabetes. This study was designed to assess the cost-effectiveness of MODY screening strategies in Hungary, which included a recent genetic test compared with no routine screening for MODY. A simulation model that combined a decision tree and an individual-level Markov model was constructed to assess the costs per quality-adjusted life year of screening strategies. Stratifying patients based on age and insulin treatment followed by a risk assessment questionnaire, a laboratory test and genetic testing was the most cost-effective strategy, saving EUR 12 and generating 0.0047 quality-adjusted life years gained per screened patient. This screening strategy could be considered for reimbursement, especially in countries with limited resources.

Identification of a novel mutation in ALMS1 in a Chinese patient with monogenic diabetic syndrome by whole-exome sequencing

Alstrom syndrome (AS) is one type of monogenic diabetic syndromes caused by mutation in the ALMS1. Due to rare prevalence and overlaps of clinical symptoms, monogenic diabetes is often misdiagnosed. Here, we report a Chinese diabetes patient with poor blood glucose control and insulin resistance. With whole-exome sequencing (WES), this patient was classified into monogenic diabetes and diagnosed as AS with one novel gene mutation identified. This study highlights the clinical application of WES in the diagnosis of monogenic diabetes.

Monogenic diabetes in adults: A multi-ancestry study reveals strong disparities in diagnosis rates and clinical presentation

AIM

Identification of monogenic diabetes (MgD) conveys benefits for patients' care. Algorithms for selecting the patients to be genetically tested have been established in EuroCaucasians, but not in non-EuroCaucasian individuals. We assessed the diagnosis rate, the phenotype of MgD, and the relevance of selection criteria, according to ancestry in patients referred for a suspected MgD.

METHODS

Seven genes (GCK, HNF1A, HNF4A, HNF1B, ABCC8, KCNJ11, INS) were analyzed in 1975 adult probands (42% non-EuroCaucasians), selected on the absence of diabetes autoantibodies and ≥2 of the following criteria: age ≤40 years and body mass index <30 kg/m² at diagnosis, and a family history of diabetes in ≥2 generations.

RESULTS

Pathogenic/likely pathogenic variants were identified in 6.2% of non-EuroCaucasian and 23.6% of EuroCaucasian patients (OR 0.21, [0.16-0.29]). Diagnosis rate was low in all non-EuroCaucasian subgroups (4.1-11.8%). Common causes of MgD (GCK, HNF1A, HNF4A), but not rare causes, were less frequent in non-EuroCaucasians than in EuroCaucasians (4.1%, vs. 21.1%, OR 0.16 [0.11-0.23]). Using ethnicity-specific body mass index cutoffs increased the diagnosis rate in several non-EuroCaucasian subgroups.

CONCLUSION

The diagnosis rate of MgD is low in non-EuroCaucasian patients, but may be improved by tailoring selection criteria according to patients'ancestry.

NEUROD1 mutation in an Italian patient with maturity onset diabetes of the young 6: a case report

BACKGROUND

Maturity Onset Diabetes of the Young (MODY) is a monogenic, autosomal, dominant disease that results in beta-cells dysfunction with consequent hyperglycaemia. It represents a rare form of diabetes (1-2% of all the cases). Sulphonylureas (SUs) represent the first-line treatment for this form of diabetes mellitus. NEUROD1 is expressed by the nervous and the pancreatic tissues, and it is necessary for the proper development of beta cells. A neurogenic differentiation factor 1 (NEUROD1) gene mutation causes beta-cells dysfunction, inadequate insulin secretion, and hyperglycaemia (MODY 6).

CASE PRESENTATION

We have documented a new missense mutation (p.Met114Leu c.340A > C) of the NEUROD1 gene, pathogenetic for diabetes mellitus, in a 48 years-old man affected by diabetes since the age of 25 and treated with insulin basal-bolus therapy. Unfortunately, an attempt to replace rapid insulin with dapagliflozin has failed. However, after the genetic diagnosis of MODY6 and treatment with SUs, he was otherwise able to suspend rapid insulin and close glucose monitoring. Interestingly, our patient had an early onset dilated cardiomyopathy, though no data about cardiac diseases in patients with MODY 6 are available.

CONCLUSIONS

Diagnostic criteria for MODY can overlap with other kinds of diabetes and most cases of genetic diabetes are still misdiagnosed as diabetes type 1 or 2. We encourage to suspect this disease in patients with a strong family history of diabetes, normal BMI, early-onset, and no autoimmunity. The appropriate therapy simplifies disease management and improves the quality of the patient's life.

The epidemiology, molecular pathogenesis, diagnosis, and treatment of maturity-onset diabetes of the young (MODY)

Background

The most common type of monogenic diabetes is maturity-onset diabetes of the young (MODY), a clinically and genetically heterogeneous group of endocrine disorders that affect 1–5% of all patients with diabetes mellitus. MODY is characterized by autosomal dominant inheritance but de novo mutations have been reported. Clinical features of MODY include young-onset hyperglycemia, evidence of residual pancreatic function, and lack of beta cell autoimmunity or insulin resistance. Glucose-lowering medications are the main treatment options for MODY. The growing recognition of the clinical and public health significance of MODY by clinicians, researchers, and governments may lead to improved screening and diagnostic practices. Consequently, this review article aims to discuss the epidemiology, pathogenesis, diagnosis, and treatment of MODY based on relevant literature published from 1975 to 2020.

Main body

The estimated prevalence of MODY from European cohorts is 1 per 10,000 in adults and 1 per 23,000 in children. Since little is known about the prevalence of MODY in African, Asian, South American, and Middle Eastern populations, further research in non-European cohorts is needed to help elucidate MODY’s exact prevalence. Currently, 14 distinct subtypes of MODY can be diagnosed through clinical assessment and genetic analysis. Various genetic mutations and disease mechanisms contribute to the pathogenesis of MODY. Management of MODY is subtype-specific and includes diet, oral antidiabetic drugs, or insulin.

Conclusions

Incidence and prevalence estimates for MODY are derived from epidemiologic studies of young people with diabetes who live in Europe, Australia, and North America. Mechanisms involved in the pathogenesis of MODY include defective transcriptional regulation, abnormal metabolic enzymes, protein misfolding, dysfunctional ion channels, or impaired signal transduction. Clinicians should understand the epidemiology and pathogenesis of MODY because such knowledge is crucial for accurate diagnosis, individualized patient management, and screening of family members.

Fasting C-peptide, a biomarker for hypoglycaemia risk in insulin-naïve people with type 2 diabetes initiating basal insulin glargine 100 U/mL

AIM

To examine the relationship between baseline fasting C-peptide (FCP) and outcomes in insulin-naïve people with type 2 diabetes initiating basal insulin glargine 100 U/mL (Gla-100).

MATERIALS AND METHODS

Post hoc pooled analysis of nine randomized, treat-to-target trials in patients with type 2 diabetes inadequately controlled on oral antihyperglycaemic drugs initiating once-daily Gla-100. Participants (n = 2165) were stratified at baseline according to FCP (≤0.40, >0.40-1.20, >1.20-2.00, >2.00 nmol/L). Glycaemic control, body weight, insulin dose and hypoglycaemia were determined at 24 weeks.

RESULTS

At baseline low FCP levels were associated with longer known diabetes duration, lower body mass index and higher fasting plasma glucose (FPG). Following Gla-100 introduction, the mean HbA1c reduction at week 24 was similar in all four FCP groups, albeit fewer people in the lowest FCP group achieved HbA1c <7.0% versus FCP groups >0.40 nmol/L. By contrast, FPG reduction and proportion reaching FPG ≤5.6 mmol/L were greatest in the lowest FCP group, diminishing at higher FCP levels. Gla-100 dose at week 24 was lowest in the ≤0.40 nmol/L FCP group and highest in the >1.20 nmol/L FCP group. Incidence and event rate of overall, nocturnal and severe hypoglycaemia were higher at week 24 in groups with lower FCP levels. In multivariable regression analysis baseline FCP, concomitant sulphonylurea use and endpoint HbA1c were strong predictors of hypoglycaemia.

CONCLUSIONS

FCP levels identified patients with type 2 diabetes experiencing different responses to basal insulin Gla-100. A low FCP identifies a markedly insulin-deficient, insulin-sensitive subgroup/phenotype with an enhanced risk of hypoglycaemia, which requires a low initial basal insulin dose, cautious titration and earlier addition of prandial glucose-lowering therapy.