Maturity-Onset Diabetes of the Young, Type II

Alternative Names

  • MODY2
  • MODY, Type 2
  • MODY, Type II
  • MODY, Glucokinase-Related
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WHO-ICD-10 version:2010

Endocrine, nutritional and metabolic diseases

Diabetes mellitus

OMIM Number

125851

Mode of Inheritance

Autosomal dominant

Gene Map Locus

7p13

Description

Maturity Onset Diabetes of the Young (MODY) refers to a group of autosomal dominant disorders, which present themselves generally in the second or third decades of life. MODYs are characterized by a reduction or loss in the capacity of the pancreas to release insulin. Six different forms of MODYs are recognized, of which MODY2 is the most common. Like all other MODYs, MODY2 is also characterized by non-ketotic hyperglycemia, presenting in young, non-obese individuals. In obese individuals, the age of onset may be further lowered. The hyperglycemia and the associated glucose intolerance, however, are of a mild nature, and the condition does not usually lead to long-term problems. Thus, microvascular complications, like nerve damages, kidney disease, and ocular complications are not as common as in other forms of diabetes.

MODY2 may be associated with pregnancy, in the form of gestational diabetes. Gestational diabetes needs to be controlled, in order to prevent complications to the fetus, including excess growth, low blood sugar, jaundice, and respiratory distress syndrome. Generally, MODY2 can be easily controlled by exercise and diet alone, without the need of any medications.

MODY2 is caused due to mutations in the Glucokinase (GCK) gene, located on chromosome 7. The glucokinase protein translated from this gene, serves as the glucose sensor for the beta cells of the pancreas. As soon as the glucose level in the blood rises over 90mg/dl, the glucokinase receptor recognizes it, and triggers insulin secretion. In mutated versions of the protein, this recognition is damaged, so that the glucokinase protein can only recognize serum glucose levels over 126-144mg/dl. The insulin trigger is, therefore, delayed, leading to the hyperglycemic condition.

Epidemiology in the Arab World

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Other Reports

Egypt

[See: Kuwait > Al-Sultan et al., 2004].

Iraq

[See: Kuwait > Al-Sultan et al., 2004].

Jordan

[See: Kuwait > Al-Sultan et al., 2004].

Kuwait

Johnstone et al. (1990) undertook a prospective case-control study in a Kuwaiti maternity hospital, between the years 1984 and 1986, to study the prevalence of glucose intolerance in pregnancy and its effect on perinatal mortality and fetal size in 731 women who delivered at the hospital and were recorded as being diabetic or having abnormal glucose tolerance. About 22% were established diabetics prior to pregnancy, 43% were classified as having gestational diabetes, and the remaining had impaired glucose tolerance. About half of the total cases were managed with insulin administration. When compared to an equal number of controls attending the same hospital, established and gestational diabetics were found to have a four times and twice greater risk, respectively, for perinatal mortality. Interestingly enough, those with impaired glucose tolerance had no stillbirths, and a lower rate of perinatal mortality when compared to the controls; the latter finding was statistically insignificant.

Al-Sultan et al. (2004) undertook a prospective descriptive study of the clinical and epidemiological features of pregnant women with gestational diabetes in Kuwait. The study included 38 Kuwaiti and 38 expatriate pregnant women suffering from gestational diabetes. Of the expatriate group, 32% were of other Arabian ethnicities, including Egyptian, Syrian, Iraqi, Jordanian, Moroccan, and Saudi Arabian. The average age among both groups of patients was around 33 years. About half the patients studied had an intermediate level of education. Among the Kuwaiti patients, 65% were obese, while in the expatriate group, only 34% were so. Other risk factors in this group of patients were found to be a positive family history of DM in first degree relatives, past history of GDM in previous pregnancies, past history of abortion, presence of glucosuria, and a past history of macrosomia. The presence of GDM was found to be positively associated with a younger age group, an intermediate level of education, past history of stillbirth(s) or abortion(s), and a past history of fetal macrosomia.

[Al-Sultan FA, Anan GD, Ahmed SAS. Clinical epidemiology of gestational diabetes in kuwait. Kuwait Med J. 2004; 36(3):195-8.]

Maksheed et al. (2004) compared the macroscopic and microscopic features of 30 placentas of patients with impaired gestational glucose tolerance (IGGT) with those of 65 controls. Mean maternal age, weight, parity, and mean birth weight of the baby were significantly higher in the IGGT group. Mean placental weight and percentage of delivery through Cesarean section were also higher, but not significantly so. The results stressed the similarity between the WHO criteria for definition of gestational diabetes and IGGT, and the need for more stringent criteria to define gestational diabetes.

Morocco

[See: Kuwait > Al-Sultan et al., 2004].

Oman

Dashora et al. (2002) screened 564 pregnant ladies for glucose intolerance by using oral glucose tolerance test (OGTT). The test was repeated two to three times with two months interval if the initial results were normal (the last being done on the seventh month of pregnancy). Out of 21.3% pregnant ladies who were found to have abnormal glucose tolerance, 1.1% had high fasting glucose levels (>6 mmol/l), while the rest (20.2%) had high post-glucose values (> 7.8 mmol/l). By early screening, over 88% of patients with GDM were diagnosed before reaching the seventh month of pregnancy, with 10% diagnosed on the second test while 2.5% diagnosed on the third test. With regard to the newborns, the mean birth weight of those born to gestational diabetic mothers was 3.13 kg (SD 0.54) while those of non diabetic mothers had a mean birth weight of 2.9 kg (SD 0.44). Three babies born to mothers with abnormal glucose tolerance had a birth weight > 4 kg, when compared to only one in the control group of 388 subjects (relative risk of 10.2). In addition, three babies (10%) in the abnormal glucose tolerance group were born with congenital anomalies as compared to only one in the control group. Dashora et al. (2002) concluded that early and multiple screening for GDM would increase its detection and hence improve pregnancy outcome, and recommended a more aggressive screening program for GDM in early pregnancy in Oman and other places where diabetes is common.

Qatar

Saad et al. (2000) performed a review of cases of Intra-Uterine Fetal Death (IUFD) in Qatar. Of the 10,188 births that took place in the year 1997, a total of 83 were stillborn. Eight of these stillbirths were attributed to maternal diabetes, giving the condition an incidence of 0.8 per 1000 births and 9.6 per 100 stillbirths. Saad et al. (2000) suggested that this high incidence could be due either to the high prevalence of pre-gestational and gestational diabetes among the Qatari population or to a poorer control of this condition.

Saudi Arabia

[See: Kuwait > Al-Sultan et al., 2004].

Al-Hakeem et al. (2016) carried out a study to determine the association between an ADRA2B polymorphism and gestational diabetes (GDM) in Saudi women.  A total of 200 pregnant women diagnosed with gestational diabetes were recruited for the study along with 300 pregnant controls.  An analysis revealed that GDM-affected women were older and had higher triglyceride and total cholesterol levels compared to controls.  They were also more likely to present with a family history of Type 2 diabetes and GDM.  Studying the 12Glu9 insertion/deletion (I>D) polymorphism of the ADRA2B gene, it was found that the DD genotype was more prevalent in GDM cases (6.5%) compared to controls (2.3%).  The Genotype ID+DD vs II (p=0.0002) and the allele D vs I (p=0.0002) were found to be statistically significant in their association with GDM.

Syria

[See: Kuwait > Al-Sultan et al., 2004].

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