Differentiating Among Type 1, Type 2 Diabetes, and MODY: Raising Awareness About the Clinical Implementation of Genetic Testing in Latin America

Objective

To describe a case of maturity-onset diabetes of the young (MODY) to highlight the importance of a correct diabetes diagnosis.

Methods

We describe a Mexican family misdiagnosed with T1D and T2D.

Results

A 36-year-old woman with diabetes and adverse outcomes during 2 pregnancies had been diagnosed with T2D 10 years ago. Genetic testing was performed due to clinical and family history, which showed a pathogenic heterozygous variant c.544G>T (p.Val182Leu) in the GCK gene. This mutation was also confirmed in most of the family members who had been diagnosed with diabetes.

Conclusion

This case highlights the need for a correct diabetes classification. Reassessment of diabetes etiology is justified, especially in individuals with unclear clinical presentation or when family history is suggestive.

Comparison of Clinical Tests for Peripheral Diabetic Neuropathy in a Type 1 Diabetes Cohort

OBJECTIVE

To examine the performance and agreement of 5 modalities for testing sensory neuropathy against a neurothesiometer among Hispanic patients with type 1 diabetes (T1D) in an outpatient setting.

METHODS

A cross-sectional study was conducted at a tertiary reference center in Mexico City. Sensitivity, specificity, predictive values, and likelihood ratios were calculated using a VibraTip device, 128 Hz tuning fork, and the Semmes-Weinstein 5.07/10 g monofilament test, Ipswich touch test (IpTT), and pinprick test (PPT). The VPT obtained using a neurothesiometer was used as the standard. Agreement between tests was calculated using kappa coefficients.

RESULTS

Our study included 78 patients (156 examinations), of whom 56.4% were females. The mean age was 38.2 ± 13.0 years, and the mean body mass index was 24.6 ± 4.8 kg/m². The best sensitivity was found for IpTT and VibraTip (89.7% and 79.3%, respectively), while the PPT and IpTT had the highest positive predictive values (94.4% and 92.9%, respectively). The highest kappa coefficients were obtained for the IpTT vs neurothesiometer (kappa coefficient [κ] = 0.893, P < .001), followed by VibraTip vs neurothesiometer (κ = 0.782, P < .001). The VibraTip vs IpTT also had a substantial agreement (κ= 0.713, P < .001).

CONCLUSION

Our findings demonstrated that the IpTT had the best diagnostic performance and agreement compared with the standard in this cohort of Hispanic patients with T1D. The IpTT is a useful, simple test for diabetic neuropathy screening. These findings support its inclusion in future guidelines for diabetic foot examination.