Neonatal diabetes


Neonatal diabetes mellitus is a disease that affects an infant and their body's ability to produce or use insulin. NDM is a monogenic form of diabetes that occurs in the first 6 months of life. Infants do not produce enough insulin, leading to an increase in glucose accumulation. It is a rare disease, occurring in only one in 100,000 to 500,000 live births. NDM can be mistaken for the much more common type 1 diabetes, but type 1 diabetes usually occurs later than the first 6 months of life. There are two types of NDM: permanent neonatal diabetes mellitus is a lifelong condition. Transient neonatal diabetes mellitus is diabetes that disappears during the infant stage but may reappear later in life.
Specific genes that can cause NDM have been identified. The onset of NDM can be caused by abnormal pancreatic development, beta cell dysfunction or accelerated beta cell dysfunction. Individuals with monogenic diabetes can pass it on to their children or future generations. Each gene associated with NDM has a different inheritance pattern.

Symptoms and signs

Common symptoms of NDM includes:
An excessive thirst and increased urination are common signs of diabetes. An individual with diabetes, have accumulated blood glucose. Their kidneys are working overtime to filter and uptake excess sugar. However, their kidneys cannot keep up, excess sugar is excreted into their urine, and this drag along fluids from the diabetic's tissues. This may lead to more frequent urination and lead to dehydration. As a diabetic individual drinks more fluids to satisfy their thirst, he or she urinates even more.
Effected areas of the body are the eyes, mouth, kidneys, heart, and pancreas. Other symptoms of dehydration includes headache, thirst and dry mouth, dizziness, tiredness, and dark colored urine. In severe cases of dehydration in diabetics, low blood pressure, sunken eyes, a weak pulse or rapid heart beat, feeling confused or fatigue. Dehydration and high blood glucose for extended period of time, the diabetic's kidney would try to filter the blood of access glucose and excrete this as urine. As the kidneys are filtering the blood, water is being removed from the blood and would need to be replaced. This leads to an increased thirst when the blood glucose is elevated in a diabetic individual. Water is needed to re-hydrate the body. Therefore, the body would take available from other parts of the body, such as saliva, tears, and from cells of the body. If access water is not available, the body would not be able to pass excess glucose out of the blood by urine and can lead to further dehydration.
Severe symptoms of NDM :
Is a diabetic complication that occurs when the body produces high levels of acid in the blood. This effects the pancreas, fat cells, and kidneys. This condition occurs when the body cannot produce enough insulin. In the absence or lack of insulin, the body of an diabetic individual will break down fat as fuel. This process produces a buildup of acids in the bloodstream known as ketones, in which leads to ketoacidosis if left untreated. The symptoms of ketoacidosis develop rapidly or within 24 hours. Symptoms of ketoacidosis are excessive thirst, frequent urination, nausea or vomiting, stomach pain, tiredness, shortness or fruity smell on breath and confusion.
A condition in which the unborn baby is smaller than he or she should be, due to the fact he or she not growing at a normal rate in the womb. Delayed growth puts the baby at risk of certain problems during pregnancy, delivery, and after birth. The problems are as follows: baby's birth weight is 90% less than normal weight, difficulty handling vaginal delivery, decreased oxygen levels, hypoglycemia, low resistance to infection, low Apgar scores, Meconium aspiration which causes breathing issues, irregular body temperature and high red blood cell count.
A condition characterized as high blood glucose, which occurs when the body has too little insulin or when the body cannot use insulin properly. Hyperglycemia affects the pancreas, kidneys, and body's tissues. Characterization of hyperglycemia is high blood glucose, high levels of sugar in the urine, frequent urination and increase thirst.
A condition characterized an extremely low blood glucose, usually less than 70 mg/dL. Areas of the body that are affected, pancreas, kidneys, and mental state.

Cause

Causes of NDM
PNDM and TNDM are inherited genetically from the mother or father of the infant. Different genetic inheritance or genetic mutations can lead to different diagnosis of NDM. The following are different types of inheritance or mutations:

Transient Neonatal Diabetes Mellitus (TNDM)

TNDM occurs within the first several days to weeks of an infant's life. Intrauterine growth restriction is commonly seen in affected individuals and defined as poor growth of an unborn baby while in his or her mother's womb. In comparison, of PNDM, the insulin dose requirement of TNDM is often lower. TNDM resolves on its own at an average age of twelve weeks. Although, individuals will relapse in 50% of cases. The parts of the body that are mostly affected are the pancreas, central nervous system and various tissues of the body.
An average of 70% of TNDM is caused by defects initiating over-expression of the father genes in the imprinted region of chromosome 6q24. There are three mechanism that can cause 6q24-related TNDM, which includes the father's DNA being defected by uniparental isodisomy on chromosome 6 and inherited duplication of 6q24. The last possible cause of TNDM, the mother's genes are affected by DNA methylation. In previous research, it has been observed the involvement of an imprinted gene within TNDM, is only expressed by the father's genetic material or chromosome, resulting in an increased expression of the imprinted gene by UPD or inherited duplication that leads to the onset of diabetes. Numerous defects within the genome can lead to over-expression of the father's defected genes in the chromosome 6q24 region and result in TNDM. However, there are two genes in this region that can be associated with TNDM:
ZAC and HYMAI Genes
ZAC is a zinc-finger protein that controls apoptosis and cell cycle arrest in PLAG1
. PLAG1 is a transcription regulator of the type 1 receptor for pituitary adenylated cyclase-activating polypeptide, which is important for insulin secretion regulation. The function of the HYMAI is unknown.
Second, chromosome 6q24-TNDM is caused by over-expression of imprinted genes at 6q24. It was discovered that a differentially methylated region is present within the shared promoter of these genes. Generally the expression of the mother's alleles of PLAGL1 and HYMAI are blocked or not expressed by DMR methylation and only the father's alleles of PLAG1 and HYMA1 are expressed. The previously listed genetic mechanisms result in twice the normal amount of these two genes and cause chromosome 6q24 TNDM.
ZFP57 Gene
Third, mother's hypomethylation defects can occur from an isolated genomic imprinting or occur as a defect called, "hypomethylation imprinted loci". HIL is defined as the loss of a methyl group in the 5-methylcytosine nucleotide at a fixed position on a chromosome. Homozygous or heterozygous ZFP57 pathogenic variant make up almost half of TNDM-HIL, but the other causes of HIL are unknown.
Moreover, half of TNDM patients that contain chromosome 6q24-related TNDM experiencing re-occurrence of diabetes during their childhood or young adulthood. The onset of insulin resistance and increased insulin requirements are associated with puberty and pregnancy initiating the relapse of diabetes. In the event of remission, individuals do not show symptoms or impairment Beta-cell function in the fasting state. Insulin secretory response to intravenous glucose loading might be abnormal in those destined to have a relapse of diabetes. TNDM caused by 6q24 genomic defects are always associated with IGUR. Other contributing factors are umbilical hernia and enlarged tongue, which are present in 9 and 30% of patients with chromosome 6q24 related TNDM.
KCNJ11 and ABCC8 Genes
In addition, TNDM initiated by the genes, KCNJ11 or ABCC8 mutations are similar to mutations in chromosome 6q24-related to TNDM. Normally, the birth weight in infants are lower in chromosome 6q24 TNDM patients and diabetes is initiated at an earlier age. There may be an overlap between chromosome 6q24 and KCNJ11 and ABCC8-related TNDM, making genetic diagnosis necessary for treatment.
INS Gene
Recessive mutations in the INS gene encoding insulin were discovered to trigger both PNDM and TNDM. Diabetes occurs because there is an decrease insulin biosynthesis as a result of homozygous mutations. Common phenotype is decreased birth weight and average age of diagnosis is one week. Previous studies show relapse of diabetes occurred at an average age of 26 weeks.

Permanent Neonatal Diabetes Mellitus (PNDM)

PNDM is associated with mutations in the Beta-cell ATP sensitive potassium channel initiated by heterozygous leading to mutations in KCNJ11 and ABCC8, which is a result of 31% and 10% of PNDM cases. Twelve percent of mutations in the insulin gene leads to PNDM.
KCNJ11 and ABCC8 Genes association with Beta-cell ATP Sensitive Potassium Channel
KCNJ11 encodes Kir6.2 and ABCC8 encodes the gene, SUR1, a member of the ATP-binding cassette transporter family, the two components of the KATP channel. This channel links glucose metabolism to insulin secretion by closing in response to ATP. Blood glucose storage into Beta-cells lead to glycolysis and cause ATP generation. The elevated ATP/adenosine diphosphate ratio causes closure of the KATP channel, and inhibit potassium efflux, that leads to depolarization of the Beta-cell membrane. Depolarization is the loss of the difference in charge between the inner and outer parts of the plasma membrane of a muscle. This occurs because of change in permeability and migration of sodium ions inside the cell. The voltage gated channels then open, allowing calcium to flow inside the channel and cause exocytosis of insulin-containing granules from the Beta-cells. Activation of defects in KCNJ11 or ABCC8 seems to make the KATP channel less sensitive to ATP, leaving more channels in an open state after high levels of glucose occurs. Resulting in the failure of insulin response to high blood glucose and leading to NDM.

Diagnosis

Diagnosis of TNDM and PNDM

The diagnostic evaluations are based upon current literature and research available on NDM. The following evaluation factors are: patients with TNDM are more likely to have intrauterine growth retardation and less likely to develop ketoacidosis than patients with PNDM. TNDM patients are younger at the age of diagnosis of diabetes and have lower insulin requirements, an overlap occurs between the two groups, therefore TNDM cannot be distinguished from PNDM based clinical feature. An early onset of diabetes mellitus is unrelated to autoimmunity in most cases, relapse of diabetes is common with TNDM, and extensive follow ups are important. In addition, molecular analysis of chromosomes 6 defects, KCNJ11 and ABCC8 genes provide a way to identify PNDM in the infant stages. Approximately,50% of PNDM are associated with the potassium channel defects which are essential consequences when changing patients from insulin therapy to sulfonylureas.

TNDM Diagnosis associated with Chromosome 6q24 Mutations

The uniparental disomy of the chromosome can be used as diagnostic method provide proof by the analysis of polymorphic markers is present on Chromosome 6. Meiotic segregation of the chromosome can be distinguished by comparing allele profiles of polymorphic makers in the child to the child's parents' genome. Normally, a total uniparental disomy of the chromosome 6 is evidenced, but partial one can be identified. Therefore, genetic markers that are close to the region of interest in chromosome 6q24 can be selected. Chromosome duplication can found by that technique also.

Medical Professionals of NDM

  • Physician
  • Endocrinologist
  • Geneticist Counselor

    Diagnostic Test of NDM

  • Fasting plasma glucose test: measures an diabetic's blood glucose after he or she has gone 8 hours without eat. This test is used to detect diabetes or pre-diabetes
  • Oral glucose tolerance test- measures an individual's blood glucose after he or she have gone at least 8 hours without eating and two hours after the diabetic individual have drunk a glucose-containing beverage. This test can be used to diagnose diabetes or pre-diabetes
  • Random plasma glucose test-the doctor checks one's blood glucose without regard to when an individual may have eaten his or her last meal. This test, along with an evaluation of symptoms, are used to diagnose diabetes but not pre-diabetes.

    Genetic Testing of NDM

  • Uniparental Disomy Test:
Samples from fetus or child and both parents are needed for analysis. Chromosome of interest must be specified on request form. For prenatal samples : if the amniotic fluid are provided. Amniotic fluid is added and charged separately. Also, if chorionic villus sample is provided, a genetic test will be added and charged separately. Microsatellites markers and polymerase chain reaction are used on the chromosomes of interest to test the DNA of the parent and child to identify the presence of uniparental disomy.
  • Intrauterine Growth Restriction
Apgar score is a test given after birth to test the baby's physical condition and evaluate if special medical care is needed.

Treatment

In many cases, neonatal diabetes may be treated with oral sulfonylureas such as glyburide. Physicians may order genetic tests to determine whether or not transitioning from insulin to sulfonylurea drugs is appropriate for a patient.
The transfer from insulin injections to oral glibenclamide therapy seems highly effective for most patients and safe. This illuminates how the molecular understanding of some monogenic form of diabetes may lead to an unexpected change of the treatment in children. This is a spectacular example of how the pharmacogenomic approach improves in a tremendous way the quality of life of the young diabetic patients.
Insulin Therapy
  • Long Acting Insulin: -is a hormone that works by lowering levels of blood glucose. It starts to work several hours after an injection and keeps working for 24 hours. It is used to manage blood glucose of diabetics. It is used to treat Type 1 and 2 diabetes in adults and Type 1 diabetes in kids as young as 6 years old.
  • Short Acting Insulin -It works similarly to natural insulin and takes up to 30 minutes and lasts for about 8 hours depending on the dosage used.
  • Intermediate Insulin: - Usually taken in combination with a short acting insulin. Intermediate acting insulin starts to activate within the first hour of injecting and enters a period of peak activity lasting for 7 hours.
Sulfonylureas
  • Sulfonylureas: This medication signals the pancreas to release insulin and help the body's cells use insulin better. This medication can lower A1C levels by 1-2%.

    Prognosis

The outcome for infants or adults with NDM have different outcomes among carriers of the disease. Among affected babies, some have PNDM while others have relapse of their diabetes and other patients may experience permanent remission. Diabetes may reoccur in the patient's childhood or adulthood. It was estimated that neonatal diabetes mellitus will be TNDM in about 50% are half of the cases.
During the Neonatal stage, the prognosis is determined by the severity of the disease, also based on how rapidly the disease is diagnosed and treated. Associated abnormalities can effect a person's prognosis. The long-term prognosis depends on the person's metabolic control, which effects the presence and complications of diabetes complications. The prognosis can be confirmed with genetic analysis to find the genetic cause of the disease. WIth proper management, the prognosis for overall health and normal brain development is normally good. It is highly advised people living with NDM seek prognosis from their health care provider.

Recent research

Clinical Trials of NDM
  • The research article is entitled, "A Successful Transition to sulfonamides treatment in male infant with novel neonatal diabetes mellitus caused by the ABBC8 gene mutation and 3 years follow up". It is a case study on the transitioning of treatments from insulin therapy to sulfonamides therapy. NDM is not initiated by an autoimmune mechanism but mutations in KATP-sensitive channel, KCNJ11, ABCC8 and INS genes are successful targets for changing treatments from insulin to sulfonamides therapy.
  • Introduction: Within this study a two month old male was admitted into the intensive care unit, because he was showing signs of diabetic ketoacidosis. Other symptoms include, respiratory tract infection, sporous, dehydration, reduced subcutaneous fat, Candida mucous infection. The infant's family history was negative for diseases of importance to hereditary and the eldest sibling was healthy.
  • Experiment: The current treatment plan consist of therapy for ketoacidosis was started upon admissions into the hospital. Also, subcutaneous insulin was given and adjusted to the glycaemic profiles and the patient was converted to euglycaemic state. After 24 hours, oral intake of insulin started and treatment continued with subcutaneous short acting insulin then intermediate acting insulin plus 2 dosage of short acting insulin. A genetic analysis was conducted for NDM and mutation of KCNJ11, ABCC8 and INS genes have been given. Sequence analysis showed a rare heterogeneous missense mutation, PF577L, in the patient's exon 12 of ABCC8 gene. This confirms diagnosis of NDM caused by heterozygous mutation in the SUR1 subunit of the pancreatic ATP-sensitive potassium channel, because his parents' white blood cells did not show signs of this mutation.
  • Results: Switching from the insulin therapy to the sulfonamides was a successful treatment. It is the current regimen used to treat NDM.
  • Discussion/Conclusion: ABCC8 gene produces SUR1 protein subunit that interacts with pancreatic ATP-sensitive potassium channel. When the channel opens a large amount of insulin is released. Mutations that occur in ABCC8 are associated with congential hyperinsulinism and PNDM or TNDM. Patients that have mutations in their potassium channel, improved their glucose levels with sulfonylurea regimen and glibenclamide showed successful results in managing glucose levels as well.
  • A 2006 study showed that 90% of patients with a KCNJ11 mutation were able to successfully transition to sulfonylurea therapy.