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.

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.

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 ).

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.

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.