Endocrine features of Prader-Willi syndrome: a narrative review focusing on genotype-phenotype correlation.

Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.

Maintaining a gluten-free diet is associated with quality of life in youths with type 1 diabetes and celiac disease.

AIM: Conflicting findings have been reported on whether in youths, the double diagnosis of type 1 diabetes (T1D) and celiac disease (CD) substantially impacts quality of life QoL, compared to subjects with T1D only. METHODS: In this study, 86 youths with double diagnosis and their parents were compared to 167 subjects with T1D only. QoL was assessed through the KINDL questionnaire. Anti-tissue transglutaminase antibodies and dietary interviews evaluated the degree of maintaining a gluten-free diet (GFD). RESULTS: We found that having CD in addition to T1D has little effect on overall QoL. However, analysis of the degree of maintaining GFD revealed significantly lower total QoL scores in groups with T1D + CD not strictly maintaining GFD compared to T1D only (p = 0.0014). The multivariable linear regression model confirmed the importance of maintaining GFD on QoL in subjects (p = 0.0066) and parents (p = 0.023). CONCLUSION: The coexistence of T1D and CD and the adoption of a GFD resulted in poor QoL levels, as in youth as in their parents, when difficulties implementing the GFD are present. Psychological support should consider the importance of maintaining GFD not only to prevent potential complications in the future but also to improve actual QoL in different subdomains.

Sustained Effectiveness of an Advanced Hybrid Closed-Loop System in a Cohort of Children and Adolescents With Type 1 Diabetes: A 1-Year Real-World Study.

OBJECTIVE: To investigate glucose metrics and identify potential predictors of the achievement of glycemic outcomes in children and adolescents during their first 12 months of MiniMed 780G use. RESEARCH DESIGN AND METHODS: This multicenter, longitudinal, real-world study recruited 368 children and adolescents with type 1 diabetes (T1D) starting SmartGuard technology between June 2020 and June 2022. Ambulatory glucose profile data were collected during a 15-day run-in period (baseline), 2 weeks after automatic mode activation, and every 3 months. The influence of covariates on glycemic outcomes after 1 year of MiniMed 780G use was assessed. RESULTS: After 15 days of automatic mode use, all glucose metrics improved compared with baseline (P < 0.001), except for time below range (P = 0.113) and coefficient of variation (P = 0.330). After 1 year, time in range (TIR) remained significantly higher than at baseline (75.3% vs. 62.8%, P < 0.001). The mean glycated hemoglobin (HbA1c) over the study duration was lower than the previous year (6.9 ± 0.6% vs. 7.4 ± 0.9%, P < 0.001). Time spent in tight range (70-140 mg/dL) was 51.1%, and the glycemia risk index was 27.6. Higher TIR levels were associated with a reduced number of automatic correction boluses (P < 0.001), fewer SmartGuard exits (P = 0.021), and longer time in automatic mode (P = 0.030). Individuals with baseline HbA1c >8% showed more relevant improvement in TIR levels (from 54.3% to 72.3%). CONCLUSIONS: Our study highlights the sustained effectiveness of MiniMed 780G among youth with T1D. Findings suggest that even children and adolescents with low therapeutic engagement may benefit from SmartGuard technology.

Glucometrics and device satisfaction in children and adolescents with type 1 diabetes using different treatment modalities: A multicenter real-world observational study.

AIMS: To analyze metabolic outcomes, diabetes impact and device satisfaction in children and adolescents with type 1 diabetes in Italy who used different treatment modalities for diabetes care in a real-life context. METHODS: In this multicenter, nationwide, cross-sectional study, 1464 participants were enrolled at a routine visit. The following treatment modalities were considered MDI + SMBG; MDI + CGM; Sensor Augmented Pump Therapy; predictive management of low glucose; Hybrid Closed Loop (HCL); Advanced Hybrid Closed Loop (AHCL). Health related quality of life was evaluated by the Italian version of the Diabetes Impact and Device Satisfaction Scale (DIDS) questionnaire. RESULTS: Patients treated with AID systems were more likely to have HbA1c ≤ 6.5 %, higher percentage of time with glucose levels between 70 and 180 mg/dL, lower percentage of time with glucose levels above 180 mg/dL, higher device satisfaction, and reduced impact of diabetes. All the therapeutic modalities with respect to MDI + CGM, except for MDI + SMBG, contributed to increase the device satisfaction. HCL and AHCL respect to MDI + CGM were associated with lower diabetes impact. CONCLUSION: Real-life use of automated insulin delivery systems is associated with reduced type 1 diabetes impact, increased device satisfaction, and achievement of glycemic goals.

Satisfaction with continuous glucose monitoring is associated with quality of life in young people with type 1 diabetes regardless of metabolic control and treatment type.

AIMS: While continuous glucose monitoring (CGM) and associated technologies have positive effects on metabolic control in young people with type 1 diabetes (T1D), less is known about their impact on quality of life (QoL). Here, we quantified CGM satisfaction and QoL in young people with T1D and their parents/caregivers to establish (i) the relationship between QoL and CGM satisfaction and (ii) the impact of the treatment regimen on QoL. METHODS: This was a cross-sectional study of children and adolescents with T1D on different treatment regimens (multiple daily injections, sensor-augmented pumps and automated insulin delivery). QoL was assessed with the KINDL instrument, and CGM satisfaction with the CGM-SAT questionnaire was evaluated in both youths with T1D and their parents. RESULTS: Two hundred and ten consecutively enrolled youths with T1D completed the KINDL and CGM-SAT questionnaires. The mean total KINDL score was greater than neutral in both subjects with T1D (3.99 ± 0.47) and parents (4.06 ± 0.40), and lower overall CGM-SAT scores (i.e., higher satisfaction) were significantly associated with higher QoL in all six KINDL subscales (p < 0.05). There were no differences in KINDL scores according to delivery technology or when participants were grouped according to optimal and sub-optimal glucose control. CONCLUSIONS: Higher satisfaction with recent CGMs was associated with better QoL in all dimensions. QoL was independent of both the insulin delivery technology and glycaemic control. CGM must be further disseminated. Attention on perceived satisfaction with CGM should be incorporated with the clinical practice to improve the well-being of children and adolescents with T1D and their families.

Progression of type 1 diabetes is associated with high levels of soluble PD-1 in islet autoantibody-positive children.

AIMS/HYPOTHESIS: Type 1 diabetes is an autoimmune disorder that is characterised by destruction of pancreatic beta cells by autoreactive T lymphocytes. Although islet autoantibodies (AAb) are an indicator of disease progression, specific immune biomarkers that can be used as target molecules to halt development of type 1 diabetes have not been discovered. Soluble immune checkpoint molecules (sICM) play a pivotal role in counteracting excessive lymphocyte responses, but their role in type 1 diabetes is unexplored. In this longitudinal study, we measured sICM levels in AAb-positive (AAb+) children to identify molecules related to type 1 diabetes progression. METHODS: We measured the levels of 14 sICM in the sera of AAb+ children (n=57) compared to those with recent-onset type 1 diabetes (n=79) and healthy children (n=44), obtained from two cohorts. AAb+ children were followed up and divided based on their progression to type 1 diabetes (AAbP) or not (AAbNP) (if they lost islet autoimmunity and did not develop disease in subsequent years). sICM were also measured in the sample taken at the visit closest to disease onset in AAbP children. RESULTS: We found that AAb+ children had a distinct sICM profile compared with healthy children and those with recent-onset type 1 diabetes. In addition, AAb+ children who progressed to type 1 diabetes (AAbP) had higher sICM concentrations than non-progressors (AAbNP). Further, sICM levels decreased in AAbP children close to disease onset. Application of Cox regression models highlighted that high concentrations of soluble programmed cell death protein 1 (sPD-1) are associated with type 1 diabetes progression (HR 1.71; 95% CI 1.16, 2.51; p=0.007). CONCLUSIONS/INTERPRETATION: This study reveals an sICM profile that is dysregulated during the preclinical stage of type 1 diabetes, and identifies sPD-1 as a pathophysiologically-relevant molecule that is associated with disease progression, offering a potential target for early interventions in autoimmune diabetes.

Maintaining the gluten-free diet: The key to improve glycemic metrics in youths with type 1 diabetes and celiac disease.

AIMS: Gluten-free diets (GFD) were considered as high glycemic index and/or high content of saturated fats; this could affect keeping good metabolic control in individuals with both type 1 diabetes (T1D) and celiac disease (CD). Our objective was to analyze time in range and other continuous glucose monitoring (CGM) metrics with real-time CGM systems, in youths with T1D and CD, compared to those with T1D only. METHODS: An observational case-control study, comparing youths aged 8-18 years with T1D and CD, with people with T1D only was performed. The degree of maintaining GFD was assessed through anti-tissue transglutaminase antibodies and dietary interview, and maintaining Mediterranean diet through the KIDMED questionnaire. RESULTS: 86 youths with T1D and CD, 167 controls with T1D only, were included in the study and the two groups reported similar real-time CGM metrics. Among the first group, 29 % were not completely maintaining GFD and compared to people with T1D only they showed higher hyperglycemia rates (% time above range: 38.72 ± 20.94 vs 34.34 ± 20.94; P = 0.039). CONCLUSIONS: Individuals with T1D and CD who maintain GFD presented similar glucose metrics compared to youths with T1D only. Individuals not strictly maintaining GFD presented higher hyperglycemia rates.

An Italian case series' description of thiamine responsive megaloblastic anemia syndrome: importance of early diagnosis and treatment.

BACKGROUND: Individuals with thiamine-responsive megaloblastic anemia (TRMA) mainly manifest macrocytic anemia, sensorineural deafness, ocular complications, and nonautoimmune diabetes. Macrocytic anemia and diabetes may be responsive to high-dosage thiamine treatment, in contrast to sensorineural deafness. Little is known about the efficacy of thiamine treatment on ocular manifestations. CASES PRESENTATION: Our objective is to report data from four Italian TRMA patients: in Cases 1, 2 and 3, the diagnosis of TRMA was made at 9, 14 and 27 months. In 3 out of 4 subjects, thiamine therapy allowed both normalization of hyperglycemia, with consequent insulin suspension, and macrocytic anemia. In all Cases, thiamine therapy did not resolve the clinical manifestation of deafness. In Cases 2 and 3, follow-up showed no blindness, unlike Case 4, in which treatment was started for megaloblastic anemia at age 7 but was increased to high doses only at age 25, when the genetic diagnosis of TRMA was performed. CONCLUSIONS: Early institution of high-dose thiamine supplementation seems to prevent the development of retinal changes and optic atrophy in TRMA patients. The spectrum of clinical manifestations is broad, and it is important to describe known Cases to gain a better understanding of this rare disease.

Satisfaction with continuous glucose monitoring is positively correlated with time in range in children with type 1 diabetes.

AIMS: Continuous glucose monitoring (CGM) can improve glucometrics in children with type 1 diabetes (T1D), and its efficacy is positively related to glucose sensor use for at least 60% of the time. We therefore investigated the relationship between CGM satisfaction as assessed by a robust questionnaire and glucose control in pediatric T1D patients. METHODS: This was a cross-sectional study of children and adolescents with T1D using CGM. The CGM Satisfaction (CGM-SAT) questionnaire was administered to patients and demographic, clinical, and glucometrics data were recorded. RESULTS: Two hundred and ten consecutively enrolled patients attending 14 Italian pediatric diabetes clinics completed the CGM-SAT questionnaire. CGM-SAT scores were not associated with age, gender, annual HbA1c, % of time with an active sensor, time above range (TAR), time below range (TBR), and coefficient of variation (CV). However, CGM satisfaction was positively correlated with time in range (TIR, p < 0.05) and negatively correlated with glycemia risk index (GRI, p < 0.05). CONCLUSIONS: CGM seems to have a positive effect on glucose control in patients with T1D. CGM satisfaction is therefore an important patient-reported outcome to assess and it is associated with increased TIR and reduced GRI.

Measures of Patient-Reported Expectations, Acceptance, and Satisfaction Using Automated Insulin Delivery Systems: A Review.

In people with type 1 diabetes, Automated Insulin Delivery (AID) systems adjust insulin delivery in response to sensor glucose data and consist of three components: an insulin pump, a continuous glucose sensor, and an algorithm that determines insulin delivery. To date, all the available AID systems require users to announce carbohydrate intake and deliver meal boluses, as well as respond to system alarms. The use of AID devices both initially and over time may be influenced by a variety of psychological factors. Analysis of patient-related outcomes should be taken into account, while recruiting applicants for the systems who are motivated and have realistic expectations in order to prevent AID dropout. We report an up-to-date summary of the available measures and semi-structured interview content to assess AID expectations, acceptance, and satisfaction using the AID systems. In conclusion, we suggest, before and after starting using AID systems, performing a specific evaluation of the related psychological implications, using validated measures and semi-structured interviews, that allows diabetes care providers to tailor their education approach to the factors that concern the patient at that time; they can teach problem-solving skills and other behavioral strategies to support sustained use of the AID system.

Glycemia Risk Index as a Novel Metric to Evaluate the Safety of Glycemic Control in Children and Adolescents with Type 1 Diabetes: An Observational, Multicenter, Real-Life Cohort Study.

Glycemia risk index (GRI) is a novel composite metric for the evaluation of the safety of glycemic management and control. The aim of this study was to evaluate GRI and its correlations with continuous glucose monitoring (CGM) metrics by analyzing real-life CGM data in 1067 children/adolescents with type 1 diabetes (T1D) using four different treatment strategies (intermittently scanned CGM [isCGM]-multiple daily injections [MDIs]; real-time CGM-MDIs; rtCGM-insulin pump; hybrid closed-loop [HCL] therapy). GRI was positively correlated with high blood glucose index, low blood glucose index, mean glycemia, its standard deviation, coefficient of variation, and HbA1c. The four treatment strategy groups showed significantly different GRI with the lowest value in the HCL group (30.8) and the highest in the isCGM-MDIs group (68.4). These findings support the use of GRI for the assessment of the glycemic risk and the safety of specific treatment in pediatric subjects with T1D.

Analysis of Corneal Deformation in Paediatric Patients Affected by Maturity Onset Diabetes of the Young Type 2.

BACKGROUND: To evaluate corneal deformation in Maturity Onset Diabetes of the Young type 2 (MODY2), paediatric subjects were analysed using a Scheimpflug-based device. The purpose of this analysis was to find new biomarkers for MODY2 disease and to gain a better understanding of the pathogenesis of the disease. METHODS: A total of 15 patients with genetic and metabolic diagnoses of MODY2 (mean age 12.8 ± 5.66 years) and 15 age-matched healthy subjects were included. The biochemical and anthropometric data of MODY2 patients were collected from clinical records, and a complete ophthalmic check with a Pentacam HR EM-3000 Specular Microscope and Corvis ST devices was performed in both groups. RESULTS: Highest concavity (HC) deflection length, Applanation 1 (A1) deflection amplitude, and A1 deflection area showed significantly lower values in MODY2 patients compared to healthy subjects. A significant positive correlation was observed between Body Mass Index (BMI) and HC deflection area and between waist circumference (WC) and the following parameters: maximum deformation amplitude, HC deformation amplitude, and HC deflection area. The glycosylated hemoglobin level (HbA1c) showed a significant positive correlation with Applanation 2 time and HC time. CONCLUSIONS: The obtained results show, for the first time, differences regarding corneal distortion features in the MODY2 population compared with healthy eyes.

A systematic review on the impact of commercially available hybrid closed loop systems on psychological outcomes in youths with type 1 diabetes and their parents.

AIM: To systematically assess the impact of commercially available hybrid closed loop (HCL) systems on psychological outcomes in youths with type 1 diabetes and their parents. METHODS: We performed a systematic review including studies published in the last 10 years. PICOS framework was used in the selection process, and evidence was assessed using the GRADE system. RESULTS: A total of 215 studies were identified after duplicate removal, and 31 studies were included in this systematic review: 20 on first-generation HCL and 11 on second-generation HCL systems. According to studies with moderate- to high-level quality of evidence, HCL systems led to better, or in some studies, unchanged psychological outcomes such as distress and burden related to diabetes management, fear of hypoglycemia, quality of life, satisfaction; instead, quality of sleep was perceived as improved, although results were not confirmed in studies using actigraphy. From semi-structured interviews, answers were more homogeneous, and participants reported a positive experience and attitude towards HCL technology, which was felt to be easy to use and apt to achieve glycemic targets. CONCLUSIONS: Evidence confirms the importance of evaluating the psychosocial needs of youths with diabetes and their families when starting HCL systems and during follow-up, and to set realistic expectations of what can be achieved along with awareness of the limitations of the systems, and educate and motivate families to overcome barriers.

Italian translation and validation of the CGM satisfaction scale questionnaire.

AIMS: Patient-reported outcomes (PROs) are increasingly important for assessing patient satisfaction with diabetes technologies. PROs must be assessed with validated questionnaires in clinical practice and research studies. Our aim was to translate and validate the Italian version of the continuous glucose monitoring (CGM) Satisfaction (CGM-SAT) scale questionnaire. METHODS: Questionnaire validation followed MAPI Research Trust guidelines and included forward translation, reconciliation, backward translation, and cognitive debriefing. RESULTS: The final version of the questionnaire was administered to 210 patients with type 1 diabetes (T1D) and 232 parents. The completion rate was excellent, with almost 100% of items answered. The overall Cronbach's coefficient was 0.71 and 0.85 for young people (patients) and parents indicating moderate and good internal consistency, respectively. Parent-young people agreement was 0.404 (95% confidence interval: 0.391-0.417), indicating moderate agreement between the two assessments. Factor analysis identified that factors assessing the "benefits" and "hassles" of CGM accounted for 33.9% and 12.9% of score variance in young people and 29.6% and 19.8% in parents, respectively. DISCUSSION: We present the successful Italian translation and validation of the CGM-SAT scale questionnaire, which will be useful for assessing satisfaction with Italian T1D patients using CGM systems.

MiniMed 780G Six-Month Use in Children and Adolescents with Type 1 Diabetes: Clinical Targets and Predictors of Optimal Glucose Control.

Background: The aim of this multicenter observational real-world study was to investigate glycemic outcomes in children and adolescents with type 1 diabetes over the first 6-month use of MiniMed™ 780G. The secondary objective was to evaluate demographic and clinical factors that may be significantly associated with the achievement of therapeutic goals. Methods: Demographic, anamnestic, and clinical data of study participants were collected at the time of enrollment. Data on ambulatory glucose profile were acquired at 3 and 6 months after activating automatic mode. Aggregated glucose metrics and device settings of the entire study period were analyzed to identify predictors of optimal glycemic control, assessed by the concomitant achievement of time in range (TIR) >70%, coefficient of variation (CV) <36%, glucose management indicator (GMI) <7%, and time below range (TBR) <4%. Results: Our study cohort consisted of 111 children and adolescents (54.1% female) aged 7-18 years. All the most relevant clinical targets were achieved according to recommendations from the International Consensus both at 3 and 6 months. When considering aggregated data, primary goals in terms of TIR, CV, GMI, and TBR were achieved, respectively, by 72.1%, 74.8%, 68.5%, and 74.8% of participants. In addition, 44 individuals (39.6%) concomitantly addressed all the above clinical targets. Regression analysis revealed that older age, briefer duration of disease, and shorter active insulin time were significant predictors of optimal glucose control. Comparing two groups of individuals stratified according to the glycated hemoglobin (HbA1c) mean value in the year preceding MiniMed 780G use, achieving glycemic targets was observed in the subgroup with lower HbA1c. Conclusions: Our study highlights the effectiveness and safety of MiniMed 780G in the pediatric population. More extensive and personalized training on advanced hybrid closed-loop use should be considered for younger people and those with long disease duration.

Optimal Prandial Timing of Insulin Bolus in Youths with Type 1 Diabetes: A Systematic Review.

The aim of this systematic review was to report the evidence on optimal prandial timing of insulin bolus in youths with type 1 diabetes. A systematic search was performed including studies published in the last 20 years (2002-2022). A PICOS framework was used in the selection process and evidence was assessed using the GRADE system. Up to one third of children and adolescents with type 1 diabetes injected rapid-acting insulin analogues after a meal. Moderate-high level quality studies showed that a pre-meal bolus compared with a bolus given at the start or after the meal was associated with a lower peak blood glucose after one to two hours, particularly after breakfast, as well as with reduced HbA1c, without any difference in the frequency of hypoglycemia. There were no differences related to the timing of bolus in total daily insulin and BMI, although these results were based on a single study. Data on individuals' treatment satisfaction were limited but did not show any effect of timing of bolus on quality of life. In addition, post-prandial administration of fast-acting analogues was superior to rapid-acting analogues on post-prandial glycemia. There was no evidence for any difference in outcomes related to the timing of insulin bolus across age groups in the two studies. In conclusion, prandial insulin injected before a meal, particularly at breakfast, provides better post-prandial glycemia and HbA1c without increasing the risk of hypoglycemia, and without affecting total daily insulin dose and BMI. For young children who often have variable eating behaviors, fast-acting analogues administered at mealtime or post-meal could provide an additional advantage.

The impact of gluten-free diet on growth, metabolic control and quality of life in youth with type 1 diabetes and celiac disease: A systematic review.

AIMS: To evaluate the impact of gluten free diet (GFD) on growth, metabolic control and quality of life in children and adolescents with type 1 diabetes (T1D) and celiac disease (CD). METHODS: A systematic search was performed including studies published in the last 15 years. PICOS framework was used in the selection process and evidence was assessed using the GRADE system. RESULTS: Overall, studies comparing youth with T1D + CD on GFD to those with T1D only, showed no significant differences in growth parameters, HbA1c, number of episodes of hypoglycemia, total daily insulin doses. Studies assessing the effect of GFD introduction showed stable BMI and HbA1c. Only two studies assessed QoL of life, which was not different between T1D + CD vs T1D only youth, as well as pre- and post-CD diagnosis and introduction of GFD. CONCLUSION: This systematic review, including only studies of moderate-high evidence quality level and reporting data on objectively assessed adherence to GFD, highlights that adherence to GFD in youth with T1D + CD leads to regular growth, stable BMI, without any negative effect on HbA1c and insulin requirements. Although assessed in few studies, lipid profile and QoL improved with the introduction of GFD.

Uric acid and cardiometabolic risk by gender in youth with type 1 diabetes.

The aim of this study was to investigate the association between uric acid (UA) and cardiometabolic risk factors (CMRFs) by sex in youth with type 1 diabetes (T1D). Retrospective data collected from 1323 children and adolescents (5-18 years; 716 boys) with T1D recruited in 9 Italian Pediatric Diabetes Centers were analyzed. CMRFs included UA, HbA1c, blood pressure (BP), cholesterol (TC), HDL, triglycerides (TG), neutrophils (N) and lymphocytes (L) count, glomerular filtration rate (eGFR) (calculated using Schwartz-Lyon equation). In boys, we found a higher age, daily insulin dose, TG, TG/HDL ratio, TC/HDL ratio, systolic BP, N/L ratio and lower HDL, and eGFR across UA tertiles (p = 0.01-0.0001). Similar results were found in girls but not for TG and systolic BP. In boys, the odds ratio (OR) of high levels of TG/HDL ratio, TC/HDL ratio, BP and mildly reduced eGFR (MRGFR) increased for 0.5 mg/dL of UA. Instead, in girls an increased levels of 0.5 mg/dL of UA were associated with high OR of TC/HDL ratio, N/L ratio and MRGFR. Uric acid may represent a useful marker for identifying youth with T1D at high cardiometabolic risk, and this association appears to vary by sex.

Wolfram Syndrome Type 2: A Systematic Review of a Not Easily Identifiable Clinical Spectrum.

BACKGROUND: Wolfram syndrome (WS) is a rare autosomal recessive disorder that is characterized by the presence of diabetes mellitus, optic atrophy and hearing loss, all of which are crucial elements for the diagnosis. WS is variably associated with diabetes insipidus, neurological disorders, urinary tract anomalies, endocrine dysfunctions and many other systemic manifestations. Since Wolfram and Wagener first described WS in 1938, new phenotypic/genotypic variants of the syndrome have been observed and the clinical picture has been significantly enriched. To date, two main subtypes of WS that associated with two different mutations are known: WS type 1 (WS1), caused by the mutation of the wolframine gene (WS1; 606201), and WS type 2 (WS2), caused by the mutation of the CISD2 gene (WS2; 604928). METHODS: A systematic review of the literature was describe the phenotypic characteristics of WS2 in order to highlight the key elements that differentiate it from the classic form. CONCLUSION: WS2 is the rarest and most recently identified subtype of WS; its clinical picture is partially overlapping with that of WS1, from which it traditionally differs by the absence of diabetes insipidus and the presence of greater bleeding tendency and peptic ulcers.