RFX6 haploinsufficiency predisposes to diabetes through impaired beta cell function.

AIMS/HYPOTHESIS: Regulatory factor X 6 (RFX6) is crucial for pancreatic endocrine development and differentiation. The RFX6 variant p.His293LeufsTer7 is significantly enriched in the Finnish population, with almost 1:250 individuals as a carrier. Importantly, the FinnGen study indicates a high predisposition for heterozygous carriers to develop type 2 and gestational diabetes. However, the precise mechanism of this predisposition remains unknown. METHODS: To understand the role of this variant in beta cell development and function, we used CRISPR technology to generate allelic series of pluripotent stem cells. We created two isogenic stem cell models: a human embryonic stem cell model; and a patient-derived stem cell model. Both were differentiated into pancreatic islet lineages (stem-cell-derived islets, SC-islets), followed by implantation in immunocompromised NOD-SCID-Gamma mice. RESULTS: Stem cell models of the homozygous variant RFX6-/- predictably failed to generate insulin-secreting pancreatic beta cells, mirroring the phenotype observed in Mitchell-Riley syndrome. Notably, at the pancreatic endocrine stage, there was an upregulation of precursor markers NEUROG3 and SOX9, accompanied by increased apoptosis. Intriguingly, heterozygous RFX6+/- SC-islets exhibited RFX6 haploinsufficiency (54.2% reduction in protein expression), associated with reduced beta cell maturation markers, altered calcium signalling and impaired insulin secretion (62% and 54% reduction in basal and high glucose conditions, respectively). However, RFX6 haploinsufficiency did not have an impact on beta cell number or insulin content. The reduced insulin secretion persisted after in vivo implantation in mice, aligning with the increased risk of variant carriers to develop diabetes. CONCLUSIONS/INTERPRETATION: Our allelic series isogenic SC-islet models represent a powerful tool to elucidate specific aetiologies of diabetes in humans, enabling the sensitive detection of aberrations in both beta cell development and function. We highlight the critical role of RFX6 in augmenting and maintaining the pancreatic progenitor pool, with an endocrine roadblock and increased cell death upon its loss. We demonstrate that RFX6 haploinsufficiency does not affect beta cell number or insulin content but does impair function, predisposing heterozygous carriers of loss-of-function variants to diabetes. DATA AVAILABILITY: Ultra-deep bulk RNA-seq data for pancreatic differentiation stages 3, 5 and 7 of H1 RFX6 genotypes are deposited in the Gene Expression Omnibus database with accession code GSE234289. Original western blot images are deposited at Mendeley ( https://data.mendeley.com/datasets/g75drr3mgw/2 ).

Prenatal, newborn and childhood factors and the timing of puberty in boys and girls.

BACKGROUND: Our aim was to determine if prenatal factors, gestational age, birth weight and length, and childhood body mass index (BMI) are associated with the timing of puberty. METHODS: Our population-based study comprised 4826 girls and 5112 boys born between 1997 and 2002. Multiple linear regression modeled the relationships between the maternal and child predictors and the age at peak height velocity (PHV). RESULTS: Maternal smoking throughout pregnancy was associated with earlier age at PHV (-1.8 months in girls, 95%CI = -3.2 to -0.3, p = 0.015 and -1.7 months in boys, 95%CI = -3.1 to -0.3, p = 0.016). Older gestational age predicted later age at PHV in boys. One SDS increase in birth weight led to 1.7 months later age at PHV in girls (95%CI = 1.2 to 2.2, p < 0.001) and 0.8 months in boys (95%CI = 0.2 to 1.3, p = 0.005). At the age of 9 years, each increment of BMI by 1 kg/m2 was associated with 1.7 months (95%CI = -1.9 to -1.6, p < 0.001) and 1.3 months (95%CI = -1.4 to -1.1, p < 0.001) earlier age at PHV in girls and boys, respectively. CONCLUSIONS: Fetal exposure to smoking can potentially exert enduring effects on pubertal timing. Birth weight and childhood nutritional status are significant determinants of pubertal timing in both sexes. IMPACT: Maternal smoking was associated with earlier timing of puberty and greater birth weight with later timing of puberty in both girls and boys. Most previous studies have focused on girls and used surveys to assess pubertal development, but we studied both sexes and used the same objective measure (age at peak height velocity) for the timing of puberty. Our study increases knowledge especially regarding factors associated with the timing of puberty among boys.

During an 18-month course of automated insulin delivery treatment, children aged 2 to 6 years achieve and maintain a higher time in tight range.

AIMS: To investigate whether the positive effects on glycaemic outcomes of 3-month automated insulin delivery (AID) achieved in 2- to 6-year-old children endure over an extended duration and how AID treatment affects time in tight range (TITR), defined as 3.9-7.8 mmol/L. RESEARCH DESIGN AND METHODS: We analysed 18 months of follow-up data from a non-randomized, prospective, single-arm clinical trial (n = 35) conducted between 2021 and 2023. The main outcome measures were changes in time in range (TIR), glycated haemoglobin (HbA1c), time above range (TAR), TITR, and mean sensor glucose (SG) value during follow-up visits (at 0, 6, 12 and 18 months). The MiniMed 780G AID system in SmartGuard Mode was used for 18 months. Parental diabetes distress was evaluated at 3 and 18 months with the validated Problem Areas in Diabetes-Parent, revised (PAID-PR) survey. RESULTS: Between 0 and 6 months, TIR and TITR increased, and HbA1c, mean SG value and TAR decreased significantly (p < 0.001); the favourable effect persisted through 18 months of follow-up. Between 3 and 18 months, PAID-PR score declined significantly (0 months: mean score 37.5; 3 months: mean score 28.6 [p = 0.06]; 18 months: mean score 24.6 [p < 0.001]). CONCLUSIONS: Treatment with AID significantly increased TITR and TIR in young children. The positive effect of AID on glycaemic control observed after 6 months persisted throughout the 18 months of follow-up. Similarly, parental diabetes distress remained reduced during 18 months follow-up. These findings are reassuring and suggest that AID treatment improves glycaemic control and reduces parental diabetes distress in young children over an extended 18-month follow-up.

Health-related quality of life and self-reported health status in adolescents with chronic health conditions before transfer of care to adult health care: an international cohort study.

BACKGROUND: Heath-related quality of life (HRQoL) is lower in adolescents with chronic health conditions compared to healthy peers. While there is evidence of some differences according to the underlying condition and gender, differences by measure and country are poorly understood. In this study we focus on the differences in HRQoL in adolescents with various chronic medical conditions in the year before transfer of care to adult health services. We also study the associations of two different HRQoL measurements to each other and to self-reported health. METHODS: We recruited 538 adolescents from New Children`s Hospital, Helsinki, Finland, and the Royal Children`s Hospital, Melbourne, Australia in 2017-2020. We used two validated HRQoL measurement instruments, Pediatric Quality of Life Inventory (PedsQL) and 16D, and a visual analog scale (VAS) for self-reported health status. RESULTS: In total, 512 adolescents (50.4% female, mean age 17.8 [SD 1.2] years), completed the survey measures. Higher HRQoL was reported in males than females in both countries (PedsQL 79.4 vs. 74.1; 16D 0.888 vs. 0.846), and in adolescents from Finland than Australia (80.6 vs. 72.2 and 0.905 vs. 0.825, p < 0.001 for all). Adolescents with diabetes, rheumatological, nephrological conditions and/or organ transplants had higher HRQoL than adolescents with neurological conditions or other disease syndromes (p < 0.001). PedsQL and 16D scores showed a strong correlation to each other (Spearman correlation coefficient r = 0.81). Using the 7-point VAS (1-7), 52% (248 of 479) considered their health status to be good (6-7) and 10% (48 of 479) rated it poor (1-2). Better self-reported health was associated with higher HRQoL. CONCLUSIONS: The HRQoL of transition aged adolescents varies between genders, diagnostic groups, and countries of residence. The association between self-reported health and HRQoL suggests that brief assessment using the VAS could identify adolescents who may benefit from in-depth HRQoL evaluation. TRIAL REGISTRATION: Trial registration name The Bridge and registration number NCT04631965 ( https://clinicaltrials.gov/ct2/show/NCT04631965 ).

Identification of monogenic variants in more than ten per cent of children without type 1 diabetes-related autoantibodies at diagnosis in the Finnish Pediatric Diabetes Register.

AIMS/HYPOTHESIS: Monogenic forms of diabetes (MODY, neonatal diabetes mellitus and syndromic forms) are rare, and affected individuals may be misclassified and treated suboptimally. The prevalence of type 1 diabetes is high in Finnish children but systematic screening for monogenic diabetes has not been conducted. We assessed the prevalence and clinical manifestations of monogenic diabetes in children initially registered with type 1 diabetes in the Finnish Pediatric Diabetes Register (FPDR) but who had no type 1 diabetes-related autoantibodies (AABs) or had only low-titre islet cell autoantibodies (ICAs) at diagnosis. METHODS: The FPDR, covering approximately 90% of newly diagnosed diabetic individuals aged ≤15 years in Finland starting from 2002, includes data on diabetes-associated HLA genotypes and AAB data (ICA, and autoantibodies against insulin, GAD, islet antigen 2 and zinc transporter 8) at diagnosis. A next generation sequencing gene panel including 42 genes was used to identify monogenic diabetes. We interpreted the variants in HNF1A by using the gene-specific standardised criteria and reported pathogenic and likely pathogenic findings only. For other genes, we also reported variants of unknown significance if an individual's phenotype suggested monogenic diabetes. RESULTS: Out of 6482 participants, we sequenced DNA for 152 (2.3%) testing negative for all AABs and 49 (0.8%) positive only for low-titre ICAs (ICAlow). A monogenic form of diabetes was revealed in 19 (12.5%) of the AAB-negative patients (14 [9.2%] had pathogenic or likely pathogenic variants) and two (4.1%) of the ICAlow group. None had ketoacidosis at diagnosis or carried HLA genotypes conferring high risk for type 1 diabetes. The affected genes were GCK, HNF1A, HNF4A, HNF1B, INS, KCNJ11, RFX6, LMNA and WFS1. A switch from insulin to oral medication was successful in four of five patients with variants in HNF1A, HNF4A or KCNJ11. CONCLUSIONS/INTERPRETATION: More than 10% of AAB-negative children with newly diagnosed diabetes had a genetic finding associated with monogenic diabetes. Because the genetic diagnosis can lead to major changes in treatment, we recommend referring all AAB-negative paediatric patients with diabetes for genetic testing. Low-titre ICAs in the absence of other AABs does not always indicate a diagnosis of type 1 diabetes.

A multigenerational study on phenotypic consequences of the most common causal variant of HNF1A-MODY.

AIMS/HYPOTHESIS: Systematic studies on the phenotypic consequences of variants causal of HNF1A-MODY are rare. Our aim was to assess the phenotype of carriers of a single HNF1A variant and genetic and clinical factors affecting the clinical spectrum. METHODS: We conducted a family-based multigenerational study by comparing heterozygous carriers of the HNF1A p.(Gly292fs) variant with the non-carrier relatives irrespective of diabetes status. During more than two decades, 145 carriers and 131 non-carriers from 12 families participated in the study, and 208 underwent an OGTT at least once. We assessed the polygenic risk score for type 2 diabetes, age at onset of diabetes and measures of body composition, as well as plasma glucose, serum insulin, proinsulin, C-peptide, glucagon and NEFA response during the OGTT. RESULTS: Half of the carriers remained free of diabetes at 23 years, one-third at 33 years and 13% even at 50 years. The median age at diagnosis was 21 years (IQR 17-35). We could not identify clinical factors affecting the age at conversion; sex, BMI, insulin sensitivity or parental carrier status had no significant effect. However, for 1 SD unit increase of a polygenic risk score for type 2 diabetes, the predicted age at diagnosis decreased by 3.2 years. During the OGTT, the carriers had higher levels of plasma glucose and lower levels of serum insulin and C-peptide than the non-carriers. The carriers were also leaner than the non-carriers (by 5.0 kg, p=0.012, and by 2.1 kg/m2 units of BMI, p=2.2 × 10-4, using the first adult measurements) and, possibly as a result of insulin deficiency, demonstrated higher lipolytic activity (with medians of NEFA at fasting 621 vs 441 µmol/l, p=0.0039; at 120 min during an OGTT 117 vs 64 µmol/l, p=3.1 × 10-5). CONCLUSIONS/INTERPRETATION: The most common causal variant of HNF1A-MODY, p.(Gly292fs), presents not only with hyperglycaemia and insulin deficiency, but also with increased lipolysis and markedly lower adult BMI. Serum insulin was more discriminative than C-peptide between carriers and non-carriers. A considerable proportion of carriers develop diabetes after young adulthood. Even among individuals with a monogenic form of diabetes, polygenic risk of diabetes modifies the age at onset of diabetes.

Onset and progression of puberty in Klinefelter syndrome.

OBJECTIVE: Klinefelter syndrome (KS) (47,XXY and variants, KS) is the most common sex chromosome disorder in humans. However, little is known about the onset and progression of puberty in patients with KS. In this study, we describe the onset and progression of puberty in a large series of boys with KS in a single tertiary centre. DESIGN AND PATIENTS: Retrospective data (Tanner stages, testicular length, testosterone supplementation, levels of luteinizing hormone [LH] and testosterone) before possible testosterone treatment on 72 KS patients with 47,XXY karyotype were reviewed, and G (n = 59 patients) and P (n = 56 patients) stages were plotted on puberty nomograms. MEASUREMENTS AND RESULTS: One boy had a delayed onset of puberty, as he was at the G1 stage at the age of 13.8 years (-2.2 SDs). No observations of delay were made of boys at Stage G2. The progression of G stages was within normal limits in the majority of patients; only few boys were late at G3 (4.1%; 1 out of 24) and G4 (7.4%; 2 out of 27). Testosterone supplementation was started at the average age of 15.5 years to 35 boys (47%), 2 of whom were over 18 years old. LH level was on average 18.2 IU/L (SD: 6.3 IU/L) and testosterone 9.1 nmol/L (SD: 3.1 nmol/L) when testosterone supplementation was started. CONCLUSIONS: Our results suggest that puberty starts within the normal age limits in boys with KS, and testosterone supplementation is not needed for the initial pubertal progression in the majority of patients.

Serum testosterone and oestradiol predict the growth response during puberty promoting treatment.

OBJECTIVE: The influence of androgens and oestrogens on growth is complex, and understanding their relative roles is important for optimising the treatment of children with various disorders of growth and puberty. DESIGN: We examined the proportional roles of androgens and oestrogens in the regulation of pubertal growth in boys with constitutional delay of growth and puberty (CDGP). The study compared 6-month low-dose intramuscular testosterone treatment (1 mg/kg/month; n = 14) with per oral letrozole treatment (2.5 mg/day; n = 14) which inhibits conversion of androgens to oestrogen. PATIENTS: Boys with CDGP were recruited to a randomized, controlled, open-label trial between 2013 and 2017 (NCT01797718). MEASUREMENTS: The patients were evaluated at 0-, 3- and 6-month visits, and morning blood samples were drawn. Linear regression models were used for data analyses. RESULTS: In the testosterone group (T-group), serum testosterone concentration correlated with serum oestradiol concentration at the beginning of the study and at 3 months, whereas in the letrozole group (Lz-group) these sex steroids correlated only at baseline. Association between serum testosterone level and growth velocity differed between the T and Lz groups, as each nmol/L increase in serum testosterone increased growth velocity 2.7 times more in the former group. Serum testosterone was the best predictor of growth velocity in both treatment groups. In the Lz-group, adding serum oestradiol to the model significantly improved the growth estimate. Only the boys with serum oestradiol above 10 pmol/L had a growth velocity above 8 cm/year. CONCLUSIONS: During puberty promoting treatment with testosterone or aromatase inhibitor letrozole, growth response is tightly correlated with serum testosterone level. A threshold level of oestrogen appears to be needed for an optimal growth rate that corresponds to normal male peak height velocity of puberty. Serum testosterone 1 week after the injection and serum testosterone and oestradiol 3 months after the onset of aromatase inhibitor treatment can be used as biomarkers for treatment response in terms of growth.

Cytosolic phosphoenolpyruvate carboxykinase deficiency: Expanding the clinical phenotype and novel laboratory findings.

Cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) deficiency due to the homozygous PCK1 variant has recently been associated with childhood-onset hypoglycemia with a recognizable pattern of abnormal urine organic acids. In this study, 21 children and 3 adult patients with genetically confirmed PEPCK-C deficiency were diagnosed during the years 2016 to 2019 and the available biochemical and clinical data were collected. All patients were ethnic Finns. Most patients (22 out of 24) had a previously published homozygous PCK1 variant c.925G>A. Two patients had a novel compound heterozygous PCK1 variant c.925G>A and c.716C>T. The laboratory results showed abnormal urine organic acid profile with increased tricarboxylic acid cycle intermediates and inadequate ketone body production during hypoglycemia. The hypoglycemic episodes manifested predominantly in the morning. Infections, fasting or poor food intake, heavy exercise, alcohol consumption, and breastfeeding were identified as triggering factors. Five patients presented with neonatal hypoglycemia. Hypoglycemic seizures occurred in half of the patients (12 out of 24). The first hypoglycemic episode often occurred at the age of 1-2 years, but it sometimes presented at a later age, and could re-occur during school age or adulthood. This study adds to the laboratory data on PEPCK-C deficiency, confirming the recognizable urine organic acid pattern and identifying deficient ketogenesis as a novel laboratory finding. The phenotype is expanded suggesting that the risk of hypoglycemia may continue into adulthood if predisposing factors are present.

The effect of COVID-19 lockdown on the glycemic control of children with type 1 diabetes.

BACKGROUND: Between March 18th and May 13th 2020, the COVID-19 pandemic outbreak in Finland resulted in the closure of schools and the limitation of daycare (i.e. lockdown). Social distancing changed the daily routines of children with type 1 diabetes (T1D). Healthcare professionals were forced to adapt to the pandemic by replacing physical outpatient visits with virtual visits. However, the influence of the lockdown on glycemic control in these patients remained unknown. METHODS: In this retrospective register study from a pediatric diabetes outpatient clinic, we analyzed the glycemic data of T1D patients (n = 245; aged 4 to 16 years) before and under the lockdown. All the participants used continuous glucose monitoring (rtCGM or iCGM), two-thirds were on insulin pumps (CSII), and one-third on multiple daily insulin injections (MDI) therapy. RESULTS: In our patient cohort, time in range (TIR, n = 209) and mean glucose levels (n = 214) were similar prior to and under the lockdown (mean change 0.44% [95%CI: -1.1-2.0], p = 0.56 and -0.13 mmol/mol [95%CI: -0.3-0.1], p = 0.17, respectively). However, children treated with CSII improved their glycemic control significantly during the lockdown: TIR improved on average 2.4% [0.6-4.2] (p = 0.010) and mean blood glucose level decreased -0.3 mmol/mol [-0.6-(-0.1)] (p = 0.008). The difference was more pronounced in girls, adolescents and patients using conventional insulin pumps. CONCLUSIONS: The glycemic control in T1D children did not deteriorate under the lockdown, and patients on CSII even improved their control, which suggests that social distancing might have allowed families to use the insulin pump more accurately as out-of-home activities were on hold.

Bone structure assessed with pQCT in prepubertal males with delayed puberty or congenital hypogonadotropic hypogonadism.

OBJECTIVE: Congenital hypogonadotropic hypogonadism (CHH) is associated with impaired bone mineral density in adulthood, whereas the estimates on bone structure in adolescents with CHH has not been previously evaluated. This study describes bone structure in CHH patients and compares it to that in boys with constitutional delay of growth and puberty (CDGP). DESIGN: A cross-sectional study. METHODS: Peripheral quantitative computed tomography (pQCT) of non-dominant arm and left leg were performed. Volumetric bone mineral density (BMD), bone mineral content, and area in trabecular and cortical bone compartments were evaluated, and bone age-adjusted Z-scores for the bone parameters were determined. RESULTS: The participants with CHH had more advanced bone age and were older, taller and heavier than the CDGP boys, yet they had lower trabecular BMD in distal radius (147.7 mg/mm3 [95% CI, 128-168 mg/mm3 ] vs. 181.2 mg/mm3 [172-192 mg/mm3 ], p = .002) and distal tibia (167.6 mg/mm3 [145-190 mg/mm3 ] vs. 207.2 mg/mm3 [187-227 mg/mm3 ], p = .012), respectively. CHH males had lower cortical thickness at diaphyseal tibia than the participants with CDGP (p = .001). These between-group differences remained significant in corresponding Z-scores adjusted for bone age and height (p = .001). In CDGP group, serum testosterone correlated positively with trabecular BMD (r = 0.51, p = .013) at distal radius, and estradiol levels correlated positively with trabecular BMD at the distal site of tibia (r = 0.58, p = .004). CONCLUSIONS: Five treatment-naïve male patients with CHH exhibited poorer trabecular BMD than untreated males with CDGP. We speculate that timely low-dose sex steroid replacement in CHH males may benefit skeletal health in adulthood.

Familial central precocious puberty: two novel MKRN3 mutations.

BACKGROUND: Paternally inherited loss-of-function mutations in MKRN3 underlie central precocious puberty (CPP). We describe clinical and genetic features of CPP patients with paternally inherited MKRN3 mutations in two independent families. METHODS: The single coding exon of MKRN3 was analyzed in three patients with CPP and their family members, followed by segregation analyses. Additionally, we report the patients' responses to GnRH analog treatment. RESULTS: A paternally inherited novel heterozygous c.939C>G, p.(Ile313Met) missense mutation affecting the RING finger domain of MKRN3 was found in a Finnish girl with CPP (age at presentation 6 years). Two Polish siblings (a girl presenting with B2 at the age of 4 years and a boy with adult size testes at the age of 9 years) had inherited a novel heterozygous MKRN3 mutation c.1237_1252delGGAGACACATGCTTTT p.(Gly413Thrfs*63) from their father. The girls were treated with GnRH analogs, which exhibited suppression of the hypothalamic-pituitary-gonadal axis. In contrast, the male patient was not treated, yet he reached his target height. CONCLUSIONS: We describe two novel MKRN3 mutations in three CPP patients. The first long-term data on a boy with CPP due to an MKRN3 mutation questions the role of GnRH analog treatment in augmenting adult height in males with this condition. IMPACT: We describe the genetic cause for central precocious puberty (CPP) in two families. This report adds two novel MKRN3 mutations to the existing literature. One of the mutations, p.(Ile313Met) affects the RING finger domain of MKRN3, which has been shown to be important for repressing the promoter activity of KISS1 and TAC3. We describe the first long-term observation of a male patient with CPP due to a paternally inherited MKRN3 loss-of-function mutation. Without GnRH analog treatment, he achieved an adult height that was in accordance with his mid-parental target height.

First year on commercial hybrid closed-loop system-experience on 111 children and adolescents with type 1 diabetes.

OBJECTIVE: The hybrid close-loop system (HCL) is a rapidly emerging treatment method for type 1 diabetes (T1D), but the long-term effectiveness of the system remains unclear. This study investigates the influence of the HCL on glycemic control in children and adolescents with T1D in a real-life setting during the first year on HCL. RESEARCH DESIGN AND METHODS: This retrospective study included all the patients (n = 111) aged 3 to 16 years with T1D who initiated the HCL system between 1st of December 2018 and 1st of December 2019 in the Helsinki University Hospital. Time in range (TIR), HbA1c, mean sensor glucose (SG) value, time below range (TBR), and SG coefficient of variance (CV) were measured at 0, 1, 3, 6, and 12 month. The changes over time were analyzed with a repeated mixed model adjusted with baseline glycemic control. RESULTS: After the initiation of HCL, all measures of glycemic control, except HbA1c, improved and the effect lasted throughout the study period. Between 0 and 12 month, TIR increased (ß = -2.5 [95%CI: -3.6 - (-1.3)], p < 0.001), whereas mean SG values (ß = -0.7 [95%CI: -0.9 - (-0.4)]), TBR (ß = -2.5 [95%CI: -3.6 - (-1.3)]), and SG CV (ß = -4.5 [95%CI: -6.3 - [-2.8]) decreased significantly (p < 0.001). Importantly, the changes occurred regardless of the age of the patient. CONCLUSIONS: Measurements of glycemic control, except HbA1c, improved significantly after the initiation of the HCL system and the favorable effect lasted throughout the follow-up. These results support the view that HCL is an efficacious treatment modality for children and adolescents with T1D of all ages.

Treatment of gonadotropin deficiency during the first year of life: long-term observation and outcome in five boys.

STUDY QUESTION: What is the peripubertal outcome of recombinant human FSH (r-hFSH) treatment during minipuberty in boys with congenital hypogonadotropic hypogonadism (CHH)? SUMMARY ANSWER: Sertoli-cell response to r-hFSH, given during the minipuberty of infancy, appears insufficient to maintain Sertoli cell function throughout childhood, as evaluated by inhibin B measurements. WHAT IS KNOWN ALREADY: Severe CHH in boys can be diagnosed during the minipuberty of infancy. Combined gonadotropin treatment at that age is suggested to improve testicular endocrine function and future fertility, yet long-term evidence is lacking. STUDY DESIGN, SIZE, DURATION: In this retrospective cohort study, we describe five CHH boys treated with r-hFSH in Helsinki University Hospital or Kuopio University Hospital between 2004 and 2018. Immediate follow-up data (0.1-1.4 months after cessation of the gonadotropin therapy) was available for four boys and long-term observations (at the age of 10.0-12.8 years) was available for three boys. As a retrospective control cohort, we provide inhibin B values of eight untreated CHH boys at the age of 12.7-17.8 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: Four patients had combined pituitary hormone deficiency, and one had CHARGE syndrome due to a CHD7 mutation. The patients were treated at the age of 0.7-4.2 months with r-hFSH (3.4 IU/kg-7.5 IU/kg per week in 2 or 3 s.c. doses for 3-4.5 months) combined with T (25 mg i.m. monthly for three months for the treatment of micropenis). Inhibin B was chosen as the primary outcome measure. MAIN RESULTS AND THE ROLE OF CHANCE: During the r-hFSH + T treatment, inhibin B increased from 76 ± 18 ng/l to 176 ± 80 ng/l (P = 0.04) and penile length increased by 81 ± 50% (P = 0.04). Unexpectedly, two boys with robust inhibin B responses in infancy demonstrated low inhibin B values in peripuberty: declining from 290 ng/l (4 months) to 16 ng/l (12.4 years), and from 207 ng/l (6 months) to 21 ng/l (12.8 years). All boys underwent orchiopexy at 2.0 ± 0.7 years of age. Inhibin B values in long-term follow-up, available for the three boys, did not significantly differ from the untreated CHH controls. LIMITATIONS, REASONS FOR CAUTION: Limitations of this retrospective study are the small number and heterogeneity of the patients and their treatment schemes. WIDER IMPLICATIONS OF THE FINDINGS: We describe the first long-term follow-up data on CHH boys treated with r-hFSH and T as infants. The results from this small patient series suggest that the effects of infant r-hFSH treatment may be transient, and further longitudinal studies are required to determine the efficacy of this treatment approach to optimise the fertility potential in this patient population. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Finnish foundation for Pediatric Research, the Academy of Finland and the Emil Aaltonen Foundation. The authors have no competing interests. TRIAL REGISTRATION NUMBER: Non-applicable.

Congenital hypogonadotropic hypogonadism, functional hypogonadotropism or constitutional delay of growth and puberty? An analysis of a large patient series from a single tertiary center.

STUDY QUESTION: What diagnoses underlie delayed puberty (DP) and predict its outcome? SUMMARY ANSWER: A multitude of different diagnoses underlie DP, and in boys a history of cryptorchidism, small testicular size and slow growth velocity (GV) predict its clinical course. WHAT IS KNOWN ALREADY: DP is caused by a variety of underlying etiologies. Hormonal markers can be used in the differential diagnosis of DP but none of them have shown complete diagnostic accuracy. STUDY DESIGN, SIZE, DURATION: Medical records of 589 patients evaluated for DP in a single tertiary care center between 2004 and 2014 were retrospectively reviewed. PARTICIPANTS/MATERIALS, SETTING, METHODS: Clinical and biochemical data of 174 boys and 70 girls who fulfilled the criteria of DP were included in the analyses. We characterized the frequencies of underlying conditions and evaluated the predictive efficacy of selected clinical and hormonal markers. MAIN RESULTS AND THE ROLE OF CHANCE: Thirty etiologies that underlie DP were identified. No markers of clinical value could be identified in the girls, whereas a history of cryptorchidism in the boys was associated with an increase in the risk of permanent hypogonadism (odds ratio 17.2 (95% CI; 3.4-85.4, P < 0.001)). The conditions that cause functional hypogonadotropic hypogonadism were more frequent in boys with a GV below 3 cm/yr than in those growing faster (19% vs 4%, P < 0.05). In this series, the most effective markers to discriminate the prepubertal boys with constitutional delay of growth and puberty (CDGP) from those with congenital hypogonadotropic hypogonadism (CHH) were testicular volume (cut-off 1.1 ml with a sensitivity of 100% and a specificity of 91%), GnRH-induced maximal LH (cut-off 4.3 IU/L; 100%, 75%) and basal inhibin B (INHB) level (cut-off 61 ng/L; 90%, 83%). LIMITATIONS, REASONS FOR CAUTION: The main limitation of the study is the retrospective design. WIDER IMPLICATIONS OF THE FINDINGS: Prior cryptorchidism and slow GV are two important clinical cues that may help clinicians to predict the clinical course of DP in boys, whereas markers of similar value could not be identified in girls. In prepubertal boys, testicular size appeared as effective as INHB and GnRH-induced LH levels in the differential diagnosis between CHH and CDGP. STUDY FUNDING/COMPETING INTERESTS: This study was supported by the Academy of Finland (268356), Foundation for Pediatric Research (7495), Sigrid Juselius Foundation (2613) and the Finnish Medical Foundation (011115). The authors have no competing interests to report. TRIAL REGISTRATION NUMBER: Not applicable.

Childhood growth in boys with congenital hypogonadotropic hypogonadism.

BACKGROUND: We describe childhood growth patterns in a series of well-characterized patients with congenital hypogonadotropic hypogonadism (CHH) with special emphasis on genotype-phenotype correlation. METHODS: We retrospectively evaluated the growth charts of 36 males with CHH (27 from Finland and 9 from Denmark). Fifteen patients (42%) had representative growth measurements during the first year of life. Genetically verified diagnosis of CHH was made in 15 (42%) patients (KAL1, FGFR1, GNRHR, or PROK2). RESULTS: We found a deceleration of growth rate during early childhood. The mean (SD) length standard deviation score (SDS) at birth (0.2 (1.6) SDS) decreased significantly during the first 3 (to -0.9 (1.2) SDS) and 6 mo of life (to -0.7 (1.3) SDS). At the average age of 3 y, mean height SDS (-0.2 (1.3) SDS) did not differ from mid-parental target height (MPH). Mean height SDS reached its nadir (-1.7 (1.4) SDS) at an average age of 15.8 (0.8) years reflecting pubertal failure. Final heights did not differ from MPH. No clear genotype-growth associations emerged. CONCLUSION: Moderate postnatal length deflection is a novel feature of CHH and may reflect early androgen deficiency. Childhood growth patterns are not of clinical value in targeting molecular genetic diagnosis of CHH.

In vivo activation of the PI3K-Akt pathway in mouse beta cells by the EGFR mutation L858R protects against diabetes.

AIMS/HYPOTHESIS: EGF receptor (EGFR) signalling is required for normal beta cell development and postnatal beta cell proliferation. We tested whether beta cell proliferation can be triggered by EGFR activation at any age and whether this can protect beta cells against apoptosis induced by diabetogenic insults in a mouse model. METHODS: We generated transgenic mice with doxycycline-inducible expression of constitutively active EGFR (L858R) (CA-EGFR) under the insulin promoter. Mice were given doxycycline at various ages for different time periods, and beta cell proliferation and mass were analysed. Mice were also challenged with streptozotocin and isolated islets exposed to cytokines. RESULTS: Expression of EGFR (L858R) led to increased phosphorylation of EGFR and Akt in pancreatic islets. CA-EGFR expression during pancreatic development (embryonic day [E]12.5 to postnatal day [P]1) increased beta cell proliferation and mass in newborn mice. However, CA-EGFR expression in adult mice did not affect beta cell mass. Expression of the transgene improved glycaemia and markedly inhibited beta cell apoptosis after a single high dose, as well as after multiple low doses of streptozotocin. In vitro mechanistic studies showed that CA-EGFR protected isolated islets from cytokine-mediated beta cell death, possibly by repressing the proapoptotic protein BCL2-like 11 (BIM). CONCLUSIONS/INTERPRETATION: Our findings show that the expression of CA-EGFR in the developing, but not in the adult pancreas stimulates beta cell replication and leads to increased beta cell mass. Importantly, CA-EGFR protects beta cells against streptozotocin- and cytokine-induced death.

Central precocious puberty in boys: secular trend and clinical features.

OBJECTIVE: Recent studies suggest that boys enter puberty at a younger age, and the incidence of male central precocious puberty (CPP) is increasing. In this study, we explore the incidence of male CPP and identify key clinical and auxological indicators for organic CPP (OCPP). DESIGN: A retrospective registry-based study. METHODS: The medical records of 43 boys treated with CPP at the Helsinki University Hospital between 1985 and 2014 were reviewed. Clinical, auxological, and endocrine data of the CPP patients were included in the analyses. RESULTS: Based on brain MRI, 26% of patients had OCPP. Between 2010 and 2014, the CPP incidence in boys was 0.34 per 10 000 (95% CI 0.20-0.60). Between 1990 and 2014, the male CPP incidence increased (incidence rate ratio [IRR] 1.10, P = .001). This increase was driven by rising idiopathic CPP (ICPP) incidence (IRR 1.11, 95% CI 1.05-1.19, P < .001), while OCPP incidence remained stable (P = .41). Compared with the patients with ICPP, the patients with OCPP were younger (P = .006), were shorter (P = .003), and had higher basal serum testosterone levels (P = .038). Combining 2 to 4 of these readily available clinical cues resulted in good to excellent (all, area under the curve 0.84-0.97, P < .001) overall performance, differentiating organic etiology from idiopathic. CONCLUSIONS: The estimated incidence of CPP in boys was 0.34 per 10 000, with 26% of cases associated with intracranial pathology. The increase in CPP incidence was driven by rising ICPP rates. Patients with OCPP were characterized by shorter stature, younger age, and higher basal testosterone levels, providing valuable cues for differentiation in addition to brain MRI. Utilizing multiple cues could guide diagnostic decision-making.

Mechanisms of thyrotropin receptor-mediated phenotype variability deciphered by gene mutations and M453T-knockin model.

The clinical spectrum of thyrotropin receptor-mediated (TSHR-mediated) diseases varies from loss-of-function mutations causing congenital hypothyroidism to constitutively active mutations (CAMs) leading to nonautoimmune hyperthyroidism (NAH). Variation at the TSHR locus has also been associated with altered lipid and bone metabolism and autoimmune thyroid diseases. However, the extrathyroidal roles of TSHR and the mechanisms underlying phenotypic variability among TSHR-mediated diseases remain unclear. Here we identified and characterized TSHR variants and factors involved in phenotypic variability in different patient cohorts, the FinnGen database, and a mouse model. TSHR CAMs were found in all 16 patients with NAH, with 1 CAM in an unexpected location in the extracellular leucine-rich repeat domain (p.S237N) and another in the transmembrane domain (p.I640V) in 2 families with distinct hyperthyroid phenotypes. In addition, screening of the FinnGen database revealed rare functional variants as well as distinct common noncoding TSHR SNPs significantly associated with thyroid phenotypes, but there was no other significant association between TSHR variants and more than 2,000 nonthyroid disease endpoints. Finally, our TSHR M453T-knockin model revealed that the phenotype was dependent on the mutation's signaling properties and was ameliorated by increased iodine intake. In summary, our data show that TSHR-mediated disease risk can be modified by variants at the TSHR locus both inside and outside the coding region as well as by altered TSHR-signaling and dietary iodine, supporting the need for personalized treatment strategies.