Diabetes Mellitus in Children and Adolescents with Genetic Syndromes

Screening for Turner syndrome-associated hyperglycemia: Evaluating hemoglobin A1c and fasting blood glucose

INTRODUCTION

Individuals with Turner syndrome (TS) are at increased risk of developing diabetes mellitus (DM). Currently, annual DM screening with hemoglobin A1c (HbA1c) with or without fasting blood glucose (FBG) is recommended starting at age 10. However, the optimal DM screening for individuals with TS is not known. The purpose of this study was to evaluate the correlation between HbA1c, FBG, and the 2-hour oral glucose tolerance test (OGTT). A second goal was to query whether optimal HbA1c and fasting (FBG) cut points for TS-associated DM and impaired glucose tolerance (IGT), as defined by the OGTT 2-hour blood glucose (BG), might differ from those for the general population.

METHODS

Individuals with TS ≥ age 10 from the TS: Genotype Phenotype study in the National Institute of Child Health and Human Development's Data and Specimen Hub (DASH) who had 2-hour OGTT BG, HbA1c, and FBG were included. Correlations between HbA1c, FBG, and 2-hour OGTT BG were evaluated. Areas under the receiver operative characteristic (ROC-AUC) curves were generated. Optimal cut points for predicting TS-associated IGT (2-hour BG ≥ 7.77 mmol/L ) and DM 2-hour BG ≥11.10 mmol/L) were determined.

RESULTS

348 individuals had complete data (2-hour OGTT BG < 7.77 mmol/L, n = 239; TS-associated IGT, n = 79; DM, n = 30). ROC-AUC was poor for HbA1c to predict IGT (0.57, 0.49-0.65) but better for DM (0.81, 0.71-0.90). ROC-AUC was also poor for FBG to predict IGT (0.63, 0.56-0.70) but better for DM (0.85, 0.77-0.93). At a cut point of 38 mmol/mol (5.6%), HbA1c had 67% sensitivity (95% CI: 47-83%) and 86% specificity (95% CI: 82-90%) for identifying TS-associated DM defined by 2-hour OGTT BG.

DISCUSSION/CONCLUSIONS

The correlation of HbA1c and 2-hour OGTT BG are lower in TS than other published studies regarding type 2 DM. HbA1c is fairly specific for DM in TS but lacks sensitivity especially at currently utilized levels. Future research should focus on characterizing individuals with TS whose glycemic status is discordant, as this may provide additional insights into the pathophysiology of glucose metabolism in TS. Longitudinal assessement of glycemia as it relates to micro- and macrovascular complications in individuals with TS will further inform DM screening in this population.

An exploratory study of plasma ceramides in comorbidities in Down syndrome

Plasma ceramide levels (henceforth, "ceramides") are biomarkers of some diseases that are comorbidities of Down syndrome (DS). We sought to determine if comorbidities in DS were associated with ceramides, studying a convenience cohort of 35 study participants, all ≥12 months old. To identify comorbidities, we reviewed the problem lists in electronic health records that were concurrent with sample collection. We placed clinically related comorbidities into one of five categories of comorbidities, henceforth, categories: obesity/overweight; autoimmune disease; congenital heart disease; bacterial infection; and central nervous system (CNS) condition. We measured the eight ceramides most frequently associated with disease using liquid chromatography-tandem mass spectrometry. We calculated a ceramide composite outcome score (CCOS) for each participant by normalizing each ceramide level to the mean for that level in the study population and then summing the normalized levels, to be proxy variable for all eight ceramides in aggregate. We used multivariable linear regression models adjusted for age and sex to test associations of categories with ceramides and with CCOSs. Post hoc, we realized that co-occurring comorbidities might interfere with establishing associations between predictor categories and ceramides and that stratified analyses might eliminate their influence on associations. We posited that CCOSs could be used to screen for associations of categories with multiple ceramides, since most diseases have been associated with more than one ceramide. We chose to omit in the stratified analyses the two categories that were the most different from one another in their associations with their CCOSs, having the most divergent regression coefficients (the highest positive and lowest negative coefficients). We first omitted one of these two divergent categories in a stratified analysis and tested in the remaining participants (those without a comorbidity in the interfering category) for associations of the other four categories with their CCOSs and then did the same for the other divergent category. In each of these two screening stratified analyses, we found one category was significantly associated with its CCOS. In the two identified categories, we then tested for associations with each of the eight ceramides, using the appropriate stratified analysis. Next, we sought to determine if the associations of the two categories with ceramides we found by omitting participants in the interfering categories held in our small sample for participants in the omitted categories as well. For each of the two categories, we therefore omitted participants without the interfering category and determined associations between the predictor category and individual ceramides in the remaining participants (those with a comorbidity in the interfering category). In the a priori analyses, autoimmune disease was inversely associated with C16 and CNS condition was inversely associated with C23. Obesity/overweight and CNS condition were the two categories with the most divergent regression coefficients (0.037 vs. -0.048). In post hoc stratified analyses, after omitting participants with obesity/overweight, thereby leaving participants without obesity/overweight, bacterial infection was associated with its CCOS and then with C14, C20, and C22. However, in the companion stratified analyses, omitting participants without obesity/overweight, thereby leaving participants with obesity/overweight, bacterial infection was not associated with any of the eight ceramides. Similarly, in post hoc stratified analyses after omitting participants with a CNS condition, thereby leaving participants without a CNS condition, obesity/overweight was associated with its CCOS and then with C14, C23, and C24. In the companion analyses, omitting participants without a CNS condition, thereby leaving participants with a CNS condition, obesity/overweight was inversely associated with C24.1. In conclusion, CNS and autoimmune disease were inversely associated with one ceramide each in a priori analyses. In post hoc analyses, we serendipitously omitted categories that interfered with associations of other categories with ceramides in stratified analyses. We found that bacterial infection was associated with three ceramides in participants without obesity/overweight and that obesity/overweight was associated with three ceramides in participants without a CNS condition. We therefore identified obesity/overweight and CNS conditions as potential confounders or effect modifiers for these associations. This is the first report of ceramides in DS and in human bacterial infection. Further study of ceramides in comorbidities of DS is justified.

Kidney disease in adults with Prader-Willi syndrome: international cohort study and systematic literature review

Background

Prader-Willi syndrome (PWS) is a rare, complex, genetic disorder characterized by hyperphagia, hypotonia, delayed psychomotor development, low muscle mass and hypothalamic dysfunction. Adults with PWS often have obesity, hypertension and type 2 diabetes mellitus (DM2), known risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD). Early symptoms of CVD and CKD may be masked by intellectual disability and inability to express physical complaints. Furthermore, kidney diseases are often asymptomatic. Therefore, renal and cardiovascular disease might be missed in patients with PWS. Microalbuminuria is an early sign of microvascular damage in the kidneys and other vascular beds. Therefore, we screened our adult PWS cohort for the presence of elevated urinary albumin and (micro)albuminuria.

Methods

We retrospectively collected anthropometric measurements, blood pressure, medical history, medication use, urine dipstick and biochemical measurements form electronic patient files. In addition, we performed a systematic literature review on kidney disease in PWS.

Results

We included 162 adults with genetically confirmed PWS (56% male, median age 28 years), of whom 44 (27%) had DM2. None had known CVD. All subjects had normal estimated glomerular filtration rate (eGFR) according to non-PWS reference intervals. Elevated urinary albumin or (micro)albuminuria was present in 28 (18%); 19 out of 75 (25%) had an increased urinary albumin-to-creatinine ratio (UACR) and 10 out of 57 (18%) had an increased urinary protein-to-creatinine ratio. Elevated urinary albumin was present at a young age (median age 26 (IQR 24-32) years) and was associated with an significantly higher BMI and LDL-cholesterol levels and higher prevalence of DM2, hypertension and dyslipidemia than those with normal UACR (p=0.027, p=0.019, p<0.001, p<0.001, p=0.011 and respectively).

Conclusion

Upon screening, one in every five adults with PWS had increased urinary albumin or (micro)albuminuria, early signs of microvascular disease. All had normal eGFR, according to non-PWS reference intervals, and none had a formal diagnosis of CVD. As muscle mass is low in PWS, creatinine levels and eGFR may be spuriously normal. Urinalysis in this patient group can be used as a screening tool for microvascular (kidney) disease. We propose an algorithm for the detection and management of microvascular disease in adults with PWS.

Hyperglycemia in Turner syndrome: Impact, mechanisms, and areas for future research

Turner syndrome (TS) is a common chromosomal disorder resulting from complete or partial absence of the second sex chromosome. Hyperglycemia, ranging from impaired glucose tolerance (IGT) to diabetes mellitus (DM), is common in TS. DM in individuals with TS is associated with an 11-fold excess in mortality. The reasons for the high prevalence of hyperglycemia in TS are not well understood even though this aspect of TS was initially reported almost 60 years ago. Karyotype, as a proxy for X chromosome (Xchr) gene dosage, has been associated with DM risk in TS - however, no specific Xchr genes or loci have been implicated in the TS hyperglycemia phenotype. The molecular genetic study of TS-related phenotypes is hampered by inability to design analyses based on familial segregation, as TS is a non-heritable genetic disorder. Mechanistic studies are confounded by a lack of adequate TS animal models, small and heterogenous study populations, and the use of medications that alter carbohydrate metabolism in the management of TS. This review summarizes and assesses existing data related to the physiological and genetic mechanisms hypothesized to underlie hyperglycemia in TS, concluding that insulin deficiency is an early defect intrinsic to TS that results in hyperglycemia. Diagnostic criteria and therapeutic options for treatment of hyperglycemia in TS are presented, while emphasizing the pitfalls and complexities of studying glucose metabolism and diagnosing hyperglycemia in the TS population.

A rare occurrence of non-classic congenital adrenal hyperplasia and type 1 diabetes mellitus in a girl with Prader-Willi Syndrome: Case report and review of the literature

Prader-Willi syndrome (PWS) is a rare genetic disorder resulting from lack of expression of the paternally derived chromosome 15q11-13, associated with several complications, including pubertal disorders, short stature, hyperphagia, obesity, glucose metabolism abnormalities, scoliosis, obstructive sleep apnea syndrome (OSAS) and behavioral problems. We report the case of a girl affected by PWS who presented at the age of 5.9 with premature pubarche, accelerated linear growth and advanced bone age (BA). She was subsequently diagnosed with non-classic congenital adrenal hyperplasia (CAH) confirmed by genetic analysis. Considering the clinical, biochemical, and genetic findings, hydrocortisone therapy was started to prevent rapid BA acceleration and severe compromission of final height. During infancy, short stature and low levels of insulin-like growth factor-1 (IGF-1) for age and gender led to suspicion of growth hormone deficiency (GHD), confirmed by stimulation testing (arginine and clonidine). rhGH therapy was administered and continued until final height was reached. During endocrinological follow up she developed impaired glucose tolerance with positive markers of β-cell autoimmunity (anti-glutamic acid decarboxylase antibodies, GAD Ab), which evolved over time into type 1 diabetes mellitus and insulin therapy with a basal-bolus scheme and an appropriate diet were needed.

Three Siblings With Woodhouse-Sakati Syndrome: A Case Report of A New Saudi Family

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive multi-system genetic disease caused by loss of function mutations in the DCAF17 gene on chromosome 2q31.1. The disease is characterized by gradual neurologic degeneration and polyendocrinopathy, particularly noteworthy for hypogonadism, beginning in early adolescence. Clinical features show wide variability with no clear genotype-phenotype correlation. The pathophysiology of WSS is unclear at present and no specific treatment is available other than hormone replacement which is administered in the course of individualized symptomatic multidisciplinary care. Genetic testing helps in confirming the diagnosis along with genetic counseling of the patient and family members. Here we report multiple cases of WSS in three siblings from a new Saudi Arabia family who were diagnosed with WSS as a consequence of a common founder mutation in the DCAF17 gene with DNA analysis showing a homozygous single nucleotide frameshift deletion (c.436delC) in exon 4 of the gene.

Characteristics of type 1 diabetes mellitus in children and adolescents with Down's syndrome in an admixed population

OBJECTIVE

People with Down's syndrome (DS) have a higher risk of developing type 1 diabetes mellitus (T1D) and may have specific clinical features compared to T1D patients without DS. This study evaluated the clinical and laboratory aspects of T1D in children and adolescents with DS in an admixed population.

METHODS

A case-control study comparing patients with T1D and DS (T1D+DS) to patients with T1D without DS (T1D controls) from two tertiary academic Hospitals in São Paulo, Brazil.

RESULTS

The sample consisted of 9 patients with T1D+DS and 18 T1D age and sex-matched controls. Anti-glutamic acid decarboxylase 65 antibodies were positive in 7/7 of the 9 T1D+DS patients, confirming the presence of diabetes autoimmunity in this group. Mean age at diagnosis of T1D was 4.9 ± 3.9 years in the T1D+DS group and 6.4 years ± 3 in the T1D control group; early diagnosis (<2 years old) occurred in three T1D+DS patients but only in one T1D control patients, both suggesting lower age of diagnosis in T1D+DS group, although without statistical significance (p = 0.282 and p = 0.093, respectively). The T1D+DS group presented lower total insulin dose (0.7 IU/kg/day ± 0.2) and HbA1c (7.2% ± 0.6) than the control group (1.0 IU/kg/day ± 0.3 and 9.1% ± 0.7, respectively) (p = 0.022 and p = 0.047, respectively).

CONCLUSION

We confirmed the autoimmune etiology of diabetes in people with DS in this admixed population. T1D+DS patients developed diabetes earlier and achieved better metabolic control with a lower insulin dose than T1D controls. These findings are in agreement with previous studies in Caucasian populations.

Monogenic diabetes mellitus and clinical implications of genetic diagnosis

Monogenic diabetes mellitus, which is diabetes caused by a defect in a single gene that is associated with β cell function or insulin action, accounts for 1% to 6% of all pediatric diabetes cases. Accurate diagnosis is important, as the effective treatment differs according to genetic etiology in some types of monogenic diabetes: high-dose sulfonylurea treatment in neonatal diabetes caused by activating mutations in KCNJ11 or ABCC8; low-dose sulfonylurea treatment in HNF1A/HNF4A-diabetes; and no treatment in GCK diabetes. Monogenic diabetes should be suspected by clinicians for certain combinations of clinical features and laboratory results, and approximately 80% of monogenic diabetes cases are misdiagnosed as type 1 diabetes or type 2 diabetes. Here, we outline the types of monogenic diabetes and the clinical implications of genetic diagnosis.

Prevalence of Hypertension and Albuminuria in Pediatric Type 2 Diabetes: A Systematic Review and Meta-analysis

Importance

Hypertension and albuminuria are markers of diabetes-related nephropathy and important factors associated with kidney outcomes in pediatric type 2 diabetes. However, their prevalence in these patients is unknown.

Objective

To measure the prevalence of hypertension and albuminuria in pediatric patients with type 2 diabetes and to evaluate the association of sex and race/ethnicity with these conditions.

Data Sources

MEDLINE, Embase, CINAHL, Cochrane Library, Web of Science, the gray literature, and references of the screened articles were searched for human studies from date of database inception to February 20, 2020.

Study Selection

Observational studies with at least 10 participants reporting the prevalence of hypertension and/or albuminuria in pediatric patients with type 2 diabetes were included. Three teams of 2 independent reviewers screened 7614 papers, of which 60 fulfilled the eligibility criteria.

Data Extraction and Synthesis

Three teams of 2 independent reviewers performed data extraction, risk of bias analysis, and level of evidence analyses. The meta-analysis was conducted using a random-effects model and followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines.

Main Outcomes and Measures

The primary outcomes included the pooled prevalence rates (percentages with 95% CI) for hypertension and albuminuria. The secondary outcomes assessed pooled prevalence rates by sex and racial/ethnic group.

Results

Sixty studies were included in the systematic review. Diabetes duration varied from inclusion at diagnosis to 15.0 years after diagnosis, and the reported mean age at diagnosis ranged from 6.5 to 21.0 years. Hypertension prevalence among 3463 participants was 25.33% (95% CI, 19.57%-31.53%). Male participants had higher hypertension risk than female participants (odds ratio [OR], 1.42 [95% CI, 1.10-1.83]), with Pacific Islander and Indigenous youth having the highest prevalence of all racial/ethnic groups (Pacific Islander youth: 26.71% [95% CI, 14.54%-40.72%]; Indigenous youth: 26.48% [95% CI, 17.34%-36.74%]; White youth: 20.95% [95% CI, 12.65%-30.57%]; African American youth: 19.04% [95% CI, 12.01%-27.23%]; Hispanic/Latino youth: 15.11% [95% CI, 6.56%-26.30%]; Asian youth: 18.37% [95% CI, 9.49%-29.23%]). Albuminuria prevalence among 2250 participants was 22.17% (95% CI, 17.34%-27.38%). Pacific Islander youth, Indigenous youth, and Asian youth had higher prevalence rates than White youth (Pacific Islander youth: 31.84% [95% CI, 11.90%-55.47%]; Indigenous youth: 24.27% [95% CI, 14.39%-35.73%]; Asian youth: 23.00% [95% CI, 18.85%-27.41%]; White youth: 12.59% [95% CI, 7.75%-18.33%]), with no sex differences (OR for male vs female participants, 0.68 [95% CI, 0.46-1.01]). Heterogeneity was high among studies, with a low to moderate risk of bias.

Conclusions and Relevance

In this study, markers of diabetes-related nephropathy were commonly detected in pediatric patients with type 2 diabetes, with a disproportionate burden noted among Pacific Islander and Indigenous youth. Personalized management strategies to target kidney outcomes are urgently needed in pediatric patients with type 2 diabetes to alleviate the burden of this condition on the kidneys.

Monogenic diabetes: A single center experience from South India

Monogenic forms of diabetes in children are frequently misclassified as either type 1 diabetes or young-onset type 2 diabetes. There is a paucity of literature regarding pediatric monogenic diabetes in the Indian population. A retrospective analysis of case records of 37 children with monogenic diabetes who were diagnosed between 2008 and 2019 in a South Indian tertiary care center was performed. The write-up describes the clinical, biochemical, and genetic characterization of these patients with the diagnoses of neonatal diabetes mellitus (15 patients), MODY (five patients), and various forms of syndromic diabetes (13 with Wolfram syndrome, two with H syndrome, one with mitochondrial diabetes, and one with thiamine responsive megaloblastic anemia).

Early Onset of Autoimmune Diabetes in Children with Down Syndrome-Two Separate Aetiologies or an Immune System Pre-Programmed for Autoimmunity?

PURPOSE OF REVIEW

An increased frequency of autoimmunity in children with Down syndrome (DS) is well described but few studies have investigated the underlying mechanisms. Recent immune system investigation of individuals with DS may shed light on the increased risk of autoimmune conditions including type 1 diabetes.

RECENT FINDINGS

Diagnosis of type 1 diabetes is accelerated in children with DS with 17% diagnosed at, or under, the age of 2 years compared with only 4% in the same age group in the general population. Counterintuitively, children with DS and diabetes have less human leukocyte antigen (HLA)-mediated susceptibility than age-matched children with autoimmune diabetes from the general population. Early onset of diabetes in DS is further highlighted by the recent description of neonatal cases of diabetes which is autoimmune but not HLA associated. There are two potential explanations for this accelerated onset: (1) an additional chromosome 21 increases the genetic and immunological risk of autoimmune diabetes or (2) there are two separate aetiologies in children with DS and diabetes. Autoimmunity in DS is an under-investigated area. In this review, we will draw on recent mechanistic studies in individuals with DS which shed some light on the increased risk of autoimmunity in children with DS and consider the current support for and against two aetiologies underlying diabetes in children with DS.

Clinical and exome sequencing findings in seven children with Bardet-Biedl syndrome from Turkey

BACKGROUND

Bardet-Biedl syndrome (BBS) is a very-rare autosomal recessive genetic disorder with severe multisystem manifestations. Genetic testing plays an important role in the early diagnosis of the disease. In this study, while trying to elucidate the genetic etiology of seven individuals with clinical BBS diagnosis from six different families, we also aimed to examine the distribution of BBS variations in this region of Turkey.

METHODS AND MATERIALS

Exome sequencing analysis is performed for clinically diagnosed patients with BBS in the present study followed by parental segregation. The unreported and previously described clinical features are presented.

RESULTS

Homozygous variants, four of which are unreported, in BBS-related genes (BBS5 [c.682-2A > G], MKKS [c.775del], BBS7 [c.849+1G > T], BBS9 [c.965G > A], BBS10 [c.145C > T], LZTFL1[c.384G > A]) are detected for all the seven individuals included in the study. The most common clinical finding is polydactyly followed by renal anomalies. The clinical features not previously described are correlated to the unreported variant.

CONCLUSIONS

In this study, exome sequencing findings are discussed and four previously unreported disease-associated variants are described including the fifth BBS-implicated LZTFL1 change and possible genotype-phenotype correlation is described.

Update on Diabetes Mellitus and Glucose Metabolism Alterations in Prader-Willi Syndrome

PURPOSE OF REVIEW

This review summarizes our current knowledge on type 2 diabetes mellitus (T2DM) and glucose metabolism alterations in Prader-Willi syndrome (PWS), the most common syndromic cause of obesity, and serves as a guide for future research and current best practice.

RECENT FINDINGS

Diabetes occurs in 10-25% of PWS patients, usually in adulthood. Severe obesity is a significant risk factor for developing of T2DM in PWS. Paradoxically, despite severe obesity, a relative hypoinsulinemia, without the expected insulin resistance, is frequently observed in PWS. The majority of PWS subjects with T2DM are asymptomatic and diabetes-related complications are infrequent. Long-term growth hormone therapy does not adversely influence glucose homeostasis in all ages, if weight gain does not occur. Early intervention to prevent obesity and the regular monitoring of glucose levels are recommended in PWS subjects. However, further studies are required to better understand the physiopathological mechanisms of T2DM in these patients.

Pediatric diabetic ketoacidosis in a patient with Down syndrome. Case report

Introduction:. Patients with Down syndrome (DS) have an increased risk of developing autoimmune diseases. This is a rare case of a pediatric patient with DS with an initial clinical profile of diabetic ketoacidosis.Case presentation:. 6-year-old male patient with symptoms suggestive of diabetes mellitus type 1 (DM1) of 15 days of evolution (polyuria, polydipsia, polyphagia and loss of 2 kilos of weight), who was admitted to the emergency department of the Hospital de San José, in Bogotá, Colombia, with uncontrollable vomiting and dehydration. The tests performed confirmed moderate ketoacidosis: glycometry: 592 mg/dL, pH: 7.19, HCO3: 10 mmol/L, PCO2: 45, PO2: 95 and lactic acid: 1.4 mmol/L. Management with isotonic fluids and intravenous insulin therapy was initiated and the patient was transferred to the pediatric intensive care unit, where ketoacidosis was controlled in approximately 10 hours. Subcutaneous insulin schedule was initiated without complications.Discussion:. This case highlights the importance of monitoring possible autoimmune complications in patients with DS, since the risk of developing them is 4.2 times higher than in the general population.Conclusion:. This case calls on to contemplate autoimmune complications in patients with DS during clinical practice. Although they are not part of the most frequent reasons for consultation, they cannot be underestimated and should be suspected and treated in a timely manner.

Understanding childhood diabetes mellitus: new pathophysiological aspects

Diabetes mellitus (DM) is not a single disease, but several pathophysiological conditions where synthesis, release, and/or action of insulin are disturbed. A progressive autoimmune/autoinflammatory destruction of islet cells is still considered the main pathophysiological event in the development of T1DM, but there is evidence that T1DM itself is a heterogeneous disease. More than 50 gene regions are closely associated with T1DM and a variety of epigenetic factors and metabolic patterns have been characterized, which may play a role in the development of T1DM. The pathogenesis and genetics of type 2 DM (T2DM) are distinct from T1DM. Genes associated with T2DM are distinct from those in T1DM. Characteristic metabolic patterns, different from those in T1DM were reported in T2DM, and some children with T2DM also express islet-antibodies. Huge progress has been made in the characterization of other specific types of DM, which had been considered very rare before. The molecular clarification of maturity-onset diabetes of the young (MODY) has greatly improved our understanding of the pathophysiology of DM. There are genetic overlaps between T2DM and monogenetic DM. Neonatal DM has been shown to be monogenetic in most cases, and genetic elucidation leads to more precise and individualized therapies. Cystic fibrosis related DM (CFRDM) should be considered a genuine part of cystic fibrosis, and not a complication, since pancreatic fibrosis does not sufficiently explain the pathophysiology of CFRDM. Disturbances of cystic fibrosis transmembrane conductance regulator (CFTR) as well as autoimmunity are involved in the pathogenesis of CFRDM.

Disorders of glucose metabolism in Prader-Willi syndrome: Results of a multicenter Italian cohort study

BACKGROUND AND AIMS

Prader-Willi syndrome (PWS) is characterized by a high incidence of altered glucose metabolism (AGM). However, epidemiological data on impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) are still discordant.

METHODS AND RESULTS

We performed a multicenter study based on 274 PWS patients [144 females, aged 20.3 ± 10.4 yrs (range: 8.1-50.1 years)] evaluating the prevalence for AGM in the entire group, and according to age (children <10 yrs; adolescents 10-18 yrs, and adults >18 yrs), Body Mass Index (BMI = kg/m(2)), gender, genotypes (deletion or uniparental disomy for chromosome 15), and GH therapy (GHT) (untreated, previously or currently treated). Altogether, AGM was detected in 67 (24.4%) of patients (0.7% IFG, 10.2% IGT, 13.5% T2DM). The prevalence of AGM was correlated to age (p = 0.001), BMI (p = 0.001) and HOMA-IR (p = 0.001). However, gender, genotype, and GHT did not influence AGM development in univariate analysis. These data were confirmed as positive predictors when inserted in a multivariate analysis model.

CONCLUSION

This study is the first report on the prevalence of AGM in a large population of PWS. Overall, PWS subjects show a high prevalence of AGM that appears more common in obese and adult subjects. Our data confirm the main role of obesity on the individual metabolic risk clustering in PWS, and thus reinforce the concept that improvement in weight control remains the most important goal of any PWS treatment program.

Vitrectomy for Proliferative Diabetic Retinopathy Associated with Klinefelter Syndrome

Introduction

We encountered a patient with Klinefelter syndrome (KS) who experienced poor outcomes after vitrectomy for proliferative diabetic retinopathy (PDR).

Case

A 44-year-old male with poorly controlled diabetes was diagnosed with KS by chromosome analysis. Ocular findings revealed severe PDR complicated with extensive preretinal hemorrhages and traction retinal detachment in his left eye, and pars plana vitrectomy was subsequently performed for treatment.

Results

A clotting hemorrhage developed during surgery and proved difficult to control. Due to postoperative bleeding and redetachment, the vitrectomy was repeated. At the second operation, we performed a silicone oil tamponade; however, the retina was redetached under the silicone oil, and the light perception vision ultimately disappeared.

Conclusion

The patient, despite showing increased blood coagulability due to diabetes, presented severe coagulopathy, likely related to KS. In patients with KS and severe PDR, the potential difficulty of vitrectomy should always be kept in mind.

Complex X chromosome rearrangement associated with multiorgan autoimmunity

BACKGROUND

Turner syndrome, a congenital condition that affects 1/2,500 births, results from absence or structural alteration of the second sex chromosome. Turner syndrome is usually associated with short stature, gonadal dysgenesis and variable dysmorphic features. The classical 45,X karyotype accounts approximately for half of all patients, the remainder exhibit mosaicism or structural abnormalities of the X chromosome. However, complex intra-X chromosomal rearrangements involving more than three breakpoints are extremely rare.

RESULTS

We present a unique case of a novel complex X chromosome rearrangement in a young female patient presenting successively a wide range of autoimmune diseases including insulin dependent diabetes mellitus, Hashimoto's thyroiditis, celiac disease, anaemia perniciosa, possible inner ear disease and severe hair loss. For the genetic evaluation, conventional cytogenetic analysis and FISH with different X specific probes were initially performed. The complexity of these results and the variety of autoimmune problems of the patient prompted us to identify the exact composition and breakpoints of the rearranged X as well as methylation status of the X chromosomes. The high resolution array-CGH (assembly GRCh37/hg19) detected single copy for the whole chromosome X short arm. Two different sized segments of Xq arm were present in three copies: one large size of 80,3 Mb from Xq11.1 to Xq27.3 region and another smaller (11,1 Mb) from Xq27.3 to Xq28 region. An 1,6 Mb Xq27.3 region of the long arm was present in two copies. Southern blot analysis identified a skewed X inactivation with ≈ 70:30 % ratios of methylated/unmethylated fragments. The G-band and FISH patterns of the rearranged X suggested the aspect of a restructured i(Xq) chromosome which was shattered and fortuitously repaired. The X-STR genotype analysis of the family detected that the patient inherited intact maternal X chromosome and a rearranged paternal X chromosome. The multiple Xq breakages and fusions as well as inverted duplication would have been expected to cause a severe Turner phenotype. However, the patient lacks many of the classic somatic features of Turner syndrome, instead she presented multiorgan autoimmune diseases.

CONCLUSIONS

The clinical data of the presented patient suggest that fragmentation of the i(Xq) chromosome elevates the risk of autoimmune diseases.

Effects of metformin in children and adolescents with Prader-Willi syndrome and early-onset morbid obesity: a pilot study

Prader-Willi syndrome (PWS) is one of the most commonly recognized causes of early-onset childhood obesity. Individuals with PWS have significant hyperphagia and decreased recognition of satiety. The exact etiology of the hyperphagia remains unknown and, therefore, untreatable. We conducted a pilot, open-label study of response to metformin in 21 children with PWS and six with early morbid obesity (EMO). Participants had significant insulin resistance and glucose intolerance on oral glucose tolerance testing (OGTT) and were started on metformin for these biochemical findings. We administered the Hyperphagia Questionnaire to parents of patients before and after starting metformin treatment. Both the PWS and EMO groups showed significant improvements in food-related distress, anxiety, and ability to be redirected away from food on the Hyperphagia Questionnaire. In the PWS group, improvements were predominantly seen in females. Within the PWS group, responders to metformin had higher 2-h glucose levels on OGTT (7.48 mmol/L vs. 4.235 mmol/L; p=0.003) and higher fasting insulin levels (116 pmol/L vs. 53.5 pmol/L; p=0.04). Additionally, parents of 5/13 individuals with PWS and 5/6 with EMO reported that their child was able to feel full while on metformin (for many this was the first time they had ever described a feeling of fullness). Metformin may improve sense of satiety and decrease anxiety about food in some individuals with PWS and EMO. Positive response to metformin may depend on the degree of hyperinsulinism and glucose intolerance. Nonetheless, the results of this pilot study bear further investigation.

Endocrine disorders in Woodhouse-Sakati syndrome: a systematic review of the literature

First described in 1983, Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive genetic disorder that leads to a spectrum of hypogonadal symptoms in adolescence. The responsible gene, DCAF17 located on chromosome 2q31.1, was discovered in 2008 and to date nine mutations have been reported in the literature. The aim of the study was to review WSS descriptively in the light of new case reports with focus on endocrine features. Phenotypic description of three patients (two females, one male) with WSS followed in the Endocrinology Department of the University Hospital of Nancy, France, and exhaustive review of the literature using the PUBMED database were performed. Of 72 patients from 29 families with documented WSS who were identified, 39 had undergone genetic testing. WSS was invariably associated with hypogonadism, decreased IGF1 and frontotemporal alopecia starting in childhood. In addition to this triad, some patients exhibited intellectual disabilities of varying severity (87 %), bilateral deafness (76 %), cervicofacial dystonia and limb pain (42 % of cases, rising to 89 % after 25 years) and diabetes (66 %, rising to 96 % after 25 years). The pathophysiology of WSS remains unclear.