We have read the analysis by Rudland et al. (1) with interest. Aside from demonstrating how the use of the new pregnancy-specific screening criteria (NSC) can provide a cost-effective approach to monogenic diabetes (maturity-onset diabetes of the young [MODY]) testing, the article highlights the crucial fact that the knowledge of a patient’s glucokinase [GCK]-MODY status may protect the fetus from harm from intensive glycemic control. We also greatly appreciate the fact that this study was carried out in a multiethnic cohort.
One point that we would like to highlight is that Southeast Asian women and Indian women are reported to have a lower disease prevalence as opposed to their Anglo-Celtic counterparts. The authors estimate a GCK-MODY prevalence rate of ∼1.4–2.7 per 100 for Anglo-Celtic women versus ∼1–1.9 per 100 for Indian women. Although the multiethnic approach to the study is certainly a step in the right direction, the given value may underreport the true prevalence of GCK-MODY in patients of Indian origin. Unfortunately, large-scale epidemiological data from India are still unavailable. In 1985, Mohan et al. (2) reported that out of 4,560 consecutive patients with diabetes seen in their clinic, 4.8% could be classified as having MODY. The diagnosis of MODY was based on the revised Tattersall criteria: age of onset of diabetes <25 years, control of diabetes possible for at least 5 years without insulin, and an absence of ketones. Subgroup classification by mutation was not done. Prior to this, in 1981, Asmal et al. (3) followed a cohort of approximately 1,445 patients of Indian origin who had diabetes. The following criteria was used to ascertain if they had insulin-independent diabetes (MODY): age at diagnosis of diabetes <35 years, duration of diabetes longer than 12 months, symptomatic presentation, control of symptoms without insulin therapy, and prevention of ketosis without insulin treatment. They ascertained that approximately 10% of the Indian patients with diabetes fit the then-used criterion for the diagnosis of MODY.
Undoubtedly, current epidemiological data may differ from a historical perspective of disease prevalence, as would the distribution of genetic mutations that result in MODY. Several studies, such as that by McNeeley and Boyko (4), document that patients of Asian ethnicity are at a higher risk for developing diabetes. Our experience has shown that out of a cohort of 152 women screened at 24–28 weeks’ gestation, 22.36% had isolated fasting hyperglycemia (≥92 mg/dL) (5). It is unclear whether the genetic predisposition to this increased risk also translates into an increased prevalence of entities like MODY in an Indian population. Furthermore, this may vary depending on which part of the Indian subcontinent a patient is from. Ongoing epidemiological studies, such as one currently under way in our institution, may ultimately shed light on this. Again, until large-scale population data are at hand, it may be difficult to truly say whether or not Indian women have a lower prevalence of GCK-MODY as compared with an Anglo-Celtic cohort.
Article Information
Duality of Interest. No potential conflicts of interest relevant to this article were reported.
The author(s) of the cited article did not respond.
