Transient neonatal diabetes mellitus in a pair of twins

Neonatal Diabetes – From Gene Discovery yo Clinical Practice Changes

Diabetes mellitus is one of the most common chronic diseases but also one of the most heterogeneous. Apart the common phenotypes of type 1 and type 2 diabetes, around 1-2% of all cases arise from a single gene mutation and are known as monogenic diabetes. Diabetes diagnosed within the first 6 months of life is known as neonatal diabetes and has been extensively studied during the last two decades. Unraveling the genetic cause and molecular mechanism of this rare diabetes phenotype led to a dramatic change in the treatment of these children who often can be switched from insulin to sulphonylurea treatment. The aim of this paper is to review the known genetic causes of neonatal diabetes and to highlight the most recent aspects of the disease caused by mutations in the KATP and insulin genes, with a special focus on the individualized treatment of these cases

Partial paternal uniparental disomy of chromosome 6 in monozygotic twins with transient neonatal diabetes mellitus and macroglossia

Transient neonatal diabetes mellitus (TNDM) usually develops within the first few weeks of life and resolves at a median age of 3 months. In most of the cases, TNDM is caused by the over-expression of a paternally expressed imprinted PLAGL1 locus on chromosome 6q24. The most frequent manifestation other than TNDM is intrauterine growth retardation (IUGR), and in some cases macroglossia. We investigated monozygotic twins who had macroglossia without IUGR. Both of the twins developed insulin-dependent hyperglycemia within the first week of life, which subsequently resolved. DNA profiling with polymerase chain reaction amplification was performed for polymorphic microsatellite markers of chromosome 6. The six informative markers, located between 6p24 and 6q15, showed normal biparental inheritance. However, the six distal informative markers, located between 6q23.2 and the 6q telomeric region, showed the absence of a maternal allele and the presence of a single paternal allele. The monosomy of the 6q telomeric region was not confirmed by chromosome banding showing 46, XX. These findings provide further evidence that partial paternal uniparental disomy of chromosome 6 (pUPD6) causes TNDM. The phenotypes other than diabetes observed in patients with partial pUPD6 may differ from those observed in patients with complete pUPD6.

Neonatal diabetes mellitus: a model for personalized medicine

Neonatal diabetes mellitus occurs in approximately 1 out of every 100,000 live births. It can be either permanent or transient, and recent studies indicate that is likely to have an underlying genetic cause, particularly when diagnosed before 6 months of age. Permanent neonatal diabetes is most commonly due to activating mutations in either of the genes encoding the two subunits of the ATP-sensitive potassium channel. In most of these patients, switching from insulin to oral sulfonylurea therapy leads to improved metabolic control, as well as possible amelioration of occasional associated neurodevelopmental disabilities. It remains to be determined what is the most appropriate treatment of other causes. The diagnosis and treatment of neonatal diabetes, therefore, represents a model for personalized medicine.

Neonatal diabetes mellitus

An explosion of work over the last decade has produced insight into the multiple hereditary causes of a nonimmunological form of diabetes diagnosed most frequently within the first 6 months of life. These studies are providing increased understanding of genes involved in the entire chain of steps that control glucose homeostasis. Neonatal diabetes is now understood to arise from mutations in genes that play critical roles in the development of the pancreas, of beta-cell apoptosis and insulin processing, as well as the regulation of insulin release. For the basic researcher, this work is providing novel tools to explore fundamental molecular and cellular processes. For the clinician, these studies underscore the need to identify the genetic cause underlying each case. It is increasingly clear that the prognosis, therapeutic approach, and genetic counseling a physician provides must be tailored to a specific gene in order to provide the best medical care.

[Transitory neonatal diabetes mellitus and pericentric chromosome 9 inversion]

Neonatal diabetes mellitus is an infrequent carbohydrate metabolism disorder with an estimated incidence of approximately one case every 400,000 to 600,000 live newborns. We present the case of a 1-month-old girl with irritability, polyuria, and a 24-h history of eagerness to feed, without fever or other associated symptoms. The patient's karyotype, obtained by amniocentesis, was 46XX with a pericentric chromosome 9 inversion. Her birth weight and length were 2,230 g (-2.65 SD) and 46 cm (-1.8 SD), respectively. Glycemic determinations during the first 72 h of extrauterine life oscillated between 90 and 157 mg/dl. Physical examination revealed general involvement, skin and mucosal pallor, evident signs of dehydration, and impaired awareness. Laboratory tests revealed glycemia: 1552 mg/dL, pH 7.16, pCO2: 23.7 mmHg; bicarbonate: 8.1 mEq/L, base excess: -19.1, and positive ketonemia. After initial stabilization, the patient was treated with intravenous fluids and continuous intravenous regular insulin infusion (initial dose 0.03-0.05 IU/kg/h). After intensive treatment, breast feeding was restored and a short-acting insulin analog was administered subcutaneously after every feed (0.1 to 0.3 IU according to capillary glycemic determinations). Insulin requirements decreased and were discontinued when the infant was 5 months old. Currently, the patient is 2 years and 7 months old and her glycemia and glycosylated hemoglobin levels are normal. Anti-islet (ICA and GAD) and anti-tyrosin phosphatase (IA2) antibodies were absent, as were mutations in the glucokinase gene (GCK).

Characterization of the methylation-sensitive promoter of the imprinted ZAC gene supports its role in transient neonatal diabetes mellitus

ZAC is a recently isolated zinc finger protein that induces apoptosis and cell cycle arrest. The corresponding gene is imprinted maternally through an unknown mechanism and maps to 6q24-q25, within the minimal interval harboring the gene responsible for transient neonatal diabetes mellitus (TNDM) and a tumor suppressor gene involved in breast cancer. Because of its functional properties, imprinting status, and expression pattern in mammary cell lines and tumors, ZAC is the best candidate so far for both disease conditions. In the present work, we delineated ZAC genomic organization and mapped its transcriptional start site. It is noteworthy that the ZAC promoter localized to the CpG island harboring the methylation imprint associated with TNDM and methylation of this promoter silenced its activity. These data indicate that the methylation mark may have a direct effect on the silencing of the ZAC imprinted allele. Our findings further strengthen the hypothesis that ZAC is the gene responsible for TNDM and suggest a novel mechanism for ZAC inactivation in breast tumors.

Neonatal diabetes mellitus: patient report and review of the literature

A female infant born at 33 weeks gestation to a gestationally diabetic mother developed apnea and respiratory distress at 6 hours of age. Laboratory investigation demonstrated persistent hyperglycemia, and the patient was treated with continuous intravenous and subsequent subcutaneous insulin therapy. Detailed laboratory investigation to reveal the etiology of hyperglycemia and further endocrine evaluation were not significant. The baby's insulin requirement has continued thereafter, and she is being followed up in an outpatient clinic still under insulin therapy at 18 months of age. Neonatal diabetes mellitus should be considered in the differential diagnosis of neonatal hyperglycemia, and it may develop in newborns born to diabetic mothers, as well as neonatal hypoglycemia. Insulin treatment with close blood glucose monitoring is essential as long as hyperglycemia persists since neonatal diabetes mellitus may be either transient or permanent and it is not possible to differentiate these two outcomes before 18 months of age.

Transient and permanent neonatal diabetes

Neonatal diabetes, which may be transient or permanent, is rare. Most patients are full-term but small- for-date infants. Typical symptoms of diabetes mellitus occur within the first 4 weeks of life, requiring insulin therapy and very strict blood glucose monitoring. Subsequent growth and psychomotor development are usually normal. In about 33% of these patients the diabetes remains permanent; the transient cases, however, often develop permanent diabetes mellitus later in life. Exocrine pancreatic insufficiency is present in some patients. Neonatal diabetes differs from type-I diabetes in many aspects and seems to form a distinct entity of inborn pancreatic malfunction.

Long-term course of neonatal diabetes

BACKGROUND

Neonatal diabetes mellitus--defined here as hyperglycemia occurring within the first month of life that lasts for at least two weeks and requires insulin therapy--is a very rare form of the disease. Little is known about it, particularly with respect to its long-term course.

METHODS

We studied two brothers who had neonatal diabetes and obtained follow-up information on 34 patients described in the literature as well as information on 21 additional patients. Forty-seven of the patients had neonatal diabetes, as defined above, and in 10 others the onset was between the first and third month of life.

RESULTS

Twenty-six of the 57 infants had permanent diabetes, 18 had transient diabetes, and 13 had transient diabetes that recurred when they were 7 to 20 years old. Neonatal diabetes was associated with the Wolcott-Rallison syndrome in six infants, hyperuricemia due to phosphoribosyl-ATP pyrophosphatase hyperactivity in two, and celiac disease in two. Forty-one of 45 neonates in whom the duration of gestation and birth weight were known were small for their gestational ages. There were two pairs of affected twins and four other families with two or more infants with neonatal diabetes, but only three parents had diabetes. The incidence of neonatal diabetes mellitus in Germany has been estimated to be 1 in 500,000 neonates.

CONCLUSIONS

Neonatal diabetes differs from insulin-dependent diabetes in that its course is highly variable. Some patients have permanent diabetes, but others have transient or lasting remissions.

Two interesting cases of transient neonatal diabetes mellitus

Two cases of transient neonatal diabetes mellitus associated with anemia, macroglossia and umbilical hernia were studied in relation to the possible etiologies that have been postulated to be responsible for this syndrome. Both patients required insulin therapy for the control of their hyperglycemia but case number two needed to be treated for 14 months before glucose normalization occurred. This patient developed classical insulin dependent diabetes mellitus during our follow-up; the HLA typing showed DR4 allele.