Predictive genetic testing in maturity‐onset diabetes of the young (MODY)

Abstract

This case emphasizes that decisions on predictive testing are very personal and require appropriate counselling.

Clinical utility gene card for: Maturity-onset diabetes of the young

“…31 The diabetes in HNF1A and HNF4A MODY is progressive and the penetrance increases with age; for HNF1A mutations, it is approximately 63% by age 25 years, 93.6% by age 50 years and 98.7% by age 75 years. 32 Patients can therefore have the mutation but be clinically unaffected at a young age, or have biochemical evidence of abnormal glucose homeostasis but be clinically asymptomatic. Patients with HNF1A and HNF4A mutations can have FBG within the non-diabetic range, but have oral glucose tolerance test results diagnostic for diabetes.…”

Type 2 Diabetes Mellitus and its Complications: From the Molecular Biology to the Clinical Practice

“…We should notice, however, that genetic research in type 2 diabetes already has not only scientific, but also prognostic and prophylactic significance, moreover it sometimes determines therapeutic decisions. For example, the molecular diagnosis of MODY that in some countries has become clinical reality is not just the domain of the scientific research [40]. It influences the mode of treatment of diabetes patients in the family, since it is generally accepted that the sulfonylurea are the agents of choice in this form of diabetes [41].…”

Maturity Onset Diabetes of the Young 5

“…(1,2,4,13) Até à data, foram identificadas mutações em 11 genes que conduzem ao fenótipo de O diagnóstico correto e a distinção de MODY de Diabetes tipo 1 e 2 são essenciais, dado que tratamentos adequados diferem, bem como a avaliação do prognóstico e a necessidade de aconselhamento genético. (14) Os familiares de primeiro grau têm uma probabilidade de 50% de adquirirem a mutação, conferindo-lhes um risco superior a 95% (penetrância elevada) de desenvolverem diabetes durante a sua vida ou, pelo menos, diminuição da tolerância à glicose ou anomalias da glicemia em jejum, até à sexta década de vida (3,7,15) . A distinção entre doentes com formas raras de Diabetes, como é o caso de MODY, de doentes com Diabetes tipo 1 e 2, revela-se um desafio diagnóstico, pois as características clínicas são semelhantes.…”