We have now talked about methods to identify genetic causes to disease. Now I would like to present you a genetic atlas of the non-autoimmune diabetes. And I will then focus in this part of my talk to describe monogenic forms of diabetes. This is an atlas of what we know about non-autoimmune diabetes. On the x-axis you will have increase in the frequency of the variation in the population. To the very right, you will have the common variance, with the frequency in the population above 5%. Then you will have the low frequency variance between 1/2% to about 5%. The rare variance between half percent and then the very rare variants. On the y-axis, you will have the effect size. What is the increase of disease risk of these variance? And you can see in the upper left corner, there are a number of monogenic diseases, they are very rare in the population, but they are causing disease and if you have these mutations, you are very likely to get the disease. So I will talk more about these monogenic forms of diabetes. This slide illustrates the age of onset of diabetes according to different genetic etiology. On the x-axis you again will have the, the age of the patient on the y-axis you will have the prevalence of the diabetic patients. And far to the left, very early after birth you can see there is a peak. Some patients, they will develop diabetes very early in life. I'll just give you an example. This is Danish patient. She was two months old when she was clinically diagnosed with diabetes. She was the third child out of three, born after the 39 weeks of gestation, normal birth weight and normal birth length. And at two months of age, she was diagnosed with a blood glucose of 48. She had ketoacidosis, and she was immediately treated with insulin pump. At that time she was the youngest patient treated with insulin pump in Denmark. She was given a half unit of insulin a day, and with that insulin dosage she was well treated. Her metabolic status before genetic, tests, testing was good. She didn't have any circulating autoantibodies. We could not measure any beta cell function, estimated from C-peptide. Blood glucose was fine, A1C was fine, and she would develop normally. Then at four years of age she was referred to our clinic. And we made a genetic test, which revealed a mutation in the Kasian J 11 gene. This figure illustrates a Beta cell. To the, in the blue area, you will have out the, the blood stream outside the the beta cell, where you will have different levels of glucose. Glucose is entering the beta cell via the GLUT-2 transporter, and there you will have phosphorylation of the glucose by the glucokynase inside. You will have metabolism of the glucose, which will increase the ATP concentration in the cell, which then will close the potassium-dependent ATP channel. When the potassium dependent ATP channel is closed, you will have membrane depolarization, calcium influx and then you will have insulin release. So this is the way the beta cell is sensing glucose, and why elevated glucose is, the signal is transmitted through the beta cell to influence secretion. And we examined the, one of the two subunit comprising the ATP sensitive potassium channel and identify a mutation there, which led to a dysfunction of the channel so it could not close. So even though the small girl she had normal glucose uptake, normal metabolism, she could not close the channel, thereby there were no membrane depolarizations, and she could not secret insulin. So what should we do? So that time it was discovered that the channel the ATP-sensitive potassium channel, is actually also the binding site for a block called sulfonylurea, and some studies in England has already revealed that treating these children with this kind of mutation might help that diabetic status. So we treated the girl with Glibenclamid at high dose and then after one week we could terminate insulin therapy. We then again looked at beta cell function and found that she now was able to secrete insulin, C-peptide was now more than 1,500. Blood glucose was normal, A1C was decreasing. So this is an example of a familial genetic approach. If you have a specific mutation then you can take a specific drug, which can help the patient. This is the electronic patient record from this patient. The green line show the dosage of insulin everyday. The red line shows the fluctuation in glucose levels, and the blue line the treatment will give Glibenclamid. You can see after approximately one week of in glibenclamide treatment then insulin treatment could be terminated, and the fluctuation of glucose is normal. This has been repeated now in many children with this kind of mutation, and as you can see to the left side of the panel, all children who were treated with insulin before their genetic diagnosis has a less optimal diabetic regulation estimated from hemoglobin A1C compared to when there was, insulin treatment was stopped and they were transferred to Sulfonylureas. So there are many forms of neonatal diabetes. I will not go through all of them. But especially the permanent neonatal diabetic forms, and especially those mutation in the KCNJ11 and ABCC8 gene are responsive very often to Sulfonylureas, so we should have an attention on diagnosing children with these forms of mutations. Now, let's move to the right on, on this cartoon illustrating age of onset. If we look at those with age of onset between 10 and 30 years, you will see that there are different forms of diabetes with onset in that age span. These, those Type 1 diabetes, there are Type 2 diabetes, those called, what we call MODY, Maturity Onset Diabetes of the Young, and there's also Mitochondrial form of diabetes. So sometimes it can be difficult, actually, to give the right diagnosis when you have onset in this age span. But let's, let's look at one of the faults. That is maturity onset diabetes of the young. It's very important when you have the patient to ask about the whether there are other family members with diabetes. In the clinic, it's very important to get information on the family history of diabetes. This slides illustrates two forms of pedigrees. To the left, the Mendelian form of inheritance, and to the right, the complex form of inheritance. Each square represents a man, the circle represent a woman. The black dotted illustrates those with the disease. The white those without disease, and you can see that several generations. So you can see the children and the grandchildren for example, in the figure to the left was a Mendelian inheritance. In that family, you can see there are siblings with diabetes, and there are diabetes in many generations. To the right, you have the more complex form of inheritance. To the upper left corner, you have a family with father and mother and three children, but only one with diabetes. Next to that, you have father and mother without diabetes with two siblings with diabetes. And in other pedigrees you will both have siblings and parents with diabetes. Those with a Mendelian form of inheritance, where you have early onset, and where you have diabetes in many generations, are those families you should suspect to have a monogenic form of diabetes. So maturity onset diabetes is of the young is a clinical diagnosis. It's a monogenetic form of diabetes. It has what we call autosomal dominant mode of inheritance. At least two generations, ideally three or more generations, should be affected consecutively. Each of diagnosis should be before 25 years of age in at least one family member, ideally in more family members. It should be non-insulin dependent. That means that either the patient has not been treated with insulin for three or more years before starting insulin treatment, those who should have insulin. Or if they have been treated with insulin from onset, that we still can measure C-peptide for years after diagnosis, diagnosis, meaning that there's some residual beta cell function. This is a clinical diagnosis of maturity cell onset of the, of the young, and in these families, we will identify the genetic cause in Europeans in may be to 70 to 80% of, of all these families. In Asian population it's much less, maybe only 20 to 30%. So here you have also a slide illustrating that even maturity onset diabetes of the young, the MODY, is very heterogeneous. There are many different genes. There are some genes many of these are in transcription factors, and then there's also mutations in the glucokinase, the GCK. The most common are in glucokinase and in HNF1A. Those with imitations and glucokinase, they have a mild defect in glucose sensing, and they have no diabetic complications. Those with imitations, in the transcription factors, they have a severe form of diabetes. Often, they progress through insulin treatment and we'll come back to that, and frequently the will have the development of diabetic complications. But let's see on the two most common forms of diabetes the glucokinase mode, which we also call model two, and the HNF1A, diabetes. What we call mode three. First MODY2. Because it's so mild, it's rare in hospital diabetic clinics. Often it's incidental, incidental identify. It could be identified in gestational diabetic women. They will always have a persistent raised fasting plasma glucose, between 5.5 and nine millimolar, most normally, and they will have that from birth. And if you do an oral glucose tolerance test, they will only have a small rise in their glycemic level. There are no extra pancreatic features. They have normal weight, and they, in the family they are often asymptomatic family members, so if you have a mutation carrier, then test the parents. This is an example of a family we have had in our clinic. You can see the father labeled M139-4. He was diagnosed when he was 52, and when we examined him, he was 62 and he was on a diet. He has elevated A1C, slightly elevated glucose levels and here's residual beta cell function estimated by C-peptide. Then there's these three kids, diagnosed five, three and one years respectively. The oldest girl M10-1, she was treated with diet, whole life. She has only slightly elevated her glycemic, but the other children, they were treated with insulin from three and one years of age respectively. And when we realize that they actually have MODY glucokinase diabetes, we knew that this was beneath benign form of diabetes, and we could terminate insulin treatment. Because it's only a glucose sensing defect they can most likely elevate the glucose level, secrete normal amounts of insulin with terminated insulin treatment, and no change in their metabolic features. This illustrates where have in the beta cell, the glucokinase, so this is the enzyme which phosphorylate with phosphate glucose when in enters GLUT-2. So we have slight elevation in glucose levels, we will have normal signaling throughout the beta cell, and normal insulin secretion. Those who have glucokinase mutations, it's safe to leave children off treatment, and often also adult, they should not have any treatment. Then let's jump to the other and the most common forms of MODY in Europeans. That's HNF1A diabetes or MODY3. It's a severe form, sometimes misdiagnosed as type one diabetes. Typically develops between 12 and 30 years. Fasting glucose may be normal initially. If you do an oral glucose tolerance test, you will often see a high increase in glucose levels during the test. The glycemic regulation is worsening with age. You'll have what we call a low renal threshold for glycosuria. So with only a slight elevation in glucose levels, you will have glucose in your urine. They are also normally not obese. And, you will have a positive family history. Normally with parents and grandparents affected as well. This is another slide from our clinic, illustrating a family. The MODY family with a HNF1A mutation. There you can see, M17 20, she was diagnosed when she was 19 years, she has a massive family history, with diabetes in many generations. She was not treated with insulin for the first many years of her diabetic life, so clinically it is a MODY family. We screened the family and identify the mutation. We also clinically know that these mutation carriers, they respond very well to sulfoylurea. So even though this patient at the age of 38 years have had insulin initiated with insulin treatment, and have had it for 6 years until she was 44 years of age, then we could stop insulin treatment. We gave her some [UNKNOWN] and in this case Tolbutamide. It optimized to a diabetic regulation, and her only complain was that she has sometimes experienced hypoglycemia. And now in 2013 I've just checked her record, she is still on sulfoylurea. So these forms, this form of diabetes you should always consider treating this with sulfoylurea. This is again the beta cell, and here we can see that an HNF1A, which is a transcription fat regulate in sans important for metabolism of glucose within the beta cell. So if you have decreased metabolism, you'll have decreased generation of ATP, you'll have decreased closure of the ATP, the ATP sensitive procession channel and decreased signalling to insulin release. But you can bypass this by giving sulphonylurea, which binds to the ATP sensitive potassium channel. This has been demonstrated and started where you compare treatment with Metformin, the drug Metformin, to Type 2 diabetic patients, that's the blue column and to patients with glycemic diabetes that's the yellow cone. And you can see when you treat with Metformin, there's no difference in the glucose level, lowering effect of the drug. But if you treat with sulfonylurea in this case Gliclazide, then the responsiveness among the HNF1A diabetic patients is much better compared to the Type 2 diabetic patients. So here you, this is a example of pharmacogenetic treatment. You should choose Sulphonylurea to treat your HNF1A diabetic patients. So, to sum up here for the monogenetic forms of diabetes, when you have permanent neonatal diabetes, age of onset of diabetes before six months it's a very important to do genetic testing, because these patients often can be treated with a drug which will be a better treatment compared to insulin treatment. If you have clinical MODY, then you should use cliny, clinical information to suggest a MODY diagnosis, then you should do the genetic tests, which makes the diagnosis, defines the MODY subtype. It will help counseling and it will help telling the patients about their prognosis and it will help you to, to choose the right treatment. So how to diagnose through a genetic diagnose. Until now you have to send the samples to a specific genetic diagnostic unit, and most units they have used Sanger sequencing and other techniques to identify mutations in the number of genes. But with the development of next generation sequencing, you could then sequence all the, these genes in one go. You could maybe choose to do a whole exome sequencing or whole genome sequencing. So in the very near future, it will be much cheaper to sequence all genes influencing glucose metabolism, so that you can examine both for neonatal diabetes and maturities onset diabetes of the young in one go. [MUSIC]
