Ethical concerns surrounding sex prediction using noninvasive prenatal screening from pediatric endocrinologists' perspective.

Noninvasive prenatal screening (NIPS) with predicted fetal sex chromosomes included in the results has become increasingly available for pregnant individuals. Predicted fetal sex chromosome results from NIPS are interpreted so as to equate sex chromosomes with sex and gender. As pediatric endocrinologists, we worry about how this use of NIPS harmfully reinforces sex and gender binaries and sets potentially inaccurate assumptions about what the identified chromosomes mean. We use a hypothetical case based on our clinical experience in which the NIPS report of fetal sex does not conform to expectations at birth to highlight ethical concerns surrounding this practice. The use of NIPS for fetal sex chromosome prediction has the potential to perpetuate stigma and bring psychological harm to parents and their future children, particularly those who are intersex, transgender, and gender diverse. The medical community should adopt an approach to the use of NIPS for fetal sex chromosome prediction that recognizes the spectrums of sex and gender to avoid reproducing stigma towards sex- and gender-diverse individuals and associated harms.

Genetic potential and height velocity during childhood and adolescence do not fully account for shorter stature in cystic fibrosis.

BACKGROUND: Despite improved health, shorter stature is common in cystic fibrosis (CF). We aimed to describe height velocity (HV) and contribution of height-related genetic variants to height (HT) in CF. METHODS: HV cohort: standard deviation scores (-Z) for HT, mid-parental height-adjusted HT (MPAH), and HV were generated using our Pediatric Center's CF Foundation registry data. HV-Z was compared with population means at each age (5-17 y), the relationship of HV-Z with HT-Z assessed, and HT-Z compared with MPAH-Z. GRS cohort: HT genetic risk-Z (HT-GRS-Z) were determined for pancreatic exocrine sufficient (PS) and insufficient (PI) youth and adults from our CF center and their relationships with HT-Z assessed. RESULTS: HV cohort: average HV-Z was normal across ages in our cohort but was 1.5× lower (p < 0.01) for each SD decrease in HT-Z. MPAH-Z was lower than HT-Z (p < 0.001). GRS cohort: HT-GRS-Z more strongly correlated with HT-Z and better explained height variance in PS (rho = 0.42; R2= 0.25) vs. PI (rho = 0.27; R2 = 0.11). CONCLUSIONS: Despite shorter stature compared with peers and mid-parental height, youth with CF generally have normal linear growth in mid- and late childhood. PI tempered the heritability of height. These results suggest that, in CF, final height is determined early in life in CF and genetic potential is attenuated by other factors. IMPACT: Children with CF remain shorter than their healthy peers despite advances in care. Our study demonstrates that children with CF have persistent shorter stature from an early age and fail to reach their genetic potential despite height velocities comparable to those of average maturing healthy peers and similar enrichment in known height increasing single-nucleotide polymorphisms (SNPs). Genetic risk scores better explained variability in pancreatic sufficient than in pancreatic insufficient individuals, suggesting that other modifying factors are in play for pancreatic insufficient individuals with CF. Given the CF Foundation's recommendation to target not only normal body mass index, but normal height percentiles as well, this study adds valuable insight to this discussion.

Endocrine Management of Ovotesticular DSD, an Index Case and Review of the Literature.

Ovotesticular Differences in Sexual Development (OT-DSD) is a rare subset of DSD with great phenotypic variability characterized by the presence of both testicular and ovarian tissue in the same individual. Here, we describe the case of 46,XX, SRY-negative baby with ambiguous genitalia and ovotestis discovered during laparoscopy. As the family decided on female gender of rearing, the testicular component of the ovotestis was removed while the ovarian component was preserved. Stemming from this case, we review the clinical presentation of OT-DSD throughout ages, the role of genetics and risk for gonadal tumors when making decisions about prophylactic gonadectomy. Finally, we summarize the most recent information of the spontaneous endocrine function, with or without conservative therapy, and fertility potential of people with OT-DSD.

Newborn Screening in the US May Miss Mild Persistent Hypothyroidism.

OBJECTIVE: To determine if newborn screening (NBS) programs for congenital hypothyroidism in the US use thyroid-stimulating hormone (TSH) cutoffs that are age adjusted to account for the physiologic 4-fold reduction in TSH concentrations over the first few days of life. STUDY DESIGN: All NBS programs in the US were contacted and asked to provide information on their NBS protocols, TSH cutoffs, and whether these cutoffs were age adjusted. RESULTS: Of 51 NBS programs, 28 request a repeat specimen if the initial eluted serum TSH concentration is mildly increased (between the cutoff and a median upper limit of 50 mU/L), whereas 14 programs perform a routine second screen in all infants. Although these specimens are typically collected between 1 week and 1 month of life, 16 of the 28 programs with a discretionary second test and 8 of 14 programs with a routine second test do not have age-adjusted TSH cutoffs after the first 48 hours of life. CONCLUSIONS: There is variation in NBS practices for screening for congenital hypothyroidism across the US, and many programs do not adjust the TSH cutoff beyond the first 2 days of life. Samples are processed when received from older infants, often to retest borderline initial results. This approach will miss congenital hypothyroidism in infants with persistent mild TSH elevations. We recommend that all NBS programs provide age-adjusted TSH cutoffs, and suggest developing a standard approach to screening for congenital hypothyroidism in the US.

Early-phase insulin secretion during mixed-meal tolerance testing predicts ß-cell function and secretory capacity in cystic fibrosis.

Insulin secretion within 30 minutes of nutrient ingestion is reduced in people with cystic fibrosis (PwCF) and pancreatic insufficiency and declines with worsening glucose tolerance. The glucose potentiated arginine (GPA) test is validated for quantifying ß-cell secretory capacity as an estimate of functional ß-cell mass but requires technical expertise and is burdensome. This study sought to compare insulin secretion during mixed-meal tolerance testing (MMTT) to GPA-derived parameters in PwCF. Methods: Secondary data analysis of CF-focused prospective studies was performed in PwCF categorized as 1) pancreatic insufficient [PI-CF] or 2) pancreatic sufficient [PS-CF] and in 3) non-CF controls. MMTT: insulin secretory rates (ISR) were derived by parametric deconvolution using 2-compartment model of C-peptide kinetics, and incremental area under the curve (AUC) was calculated for 30, 60 and 180-minutes. GPA: acute insulin (AIR) and C-peptide responses (ACR) were calculated as average post-arginine insulin or C-peptide response minus pre-arginine insulin or C-peptide under fasting (AIRarg and ACRarg), ~230 mg/dL (AIRpot and ACRpot), and ~340 mg/dL (AIRmax and ACRmax) hyperglycemic clamp conditions. Relationships of MMTT to GPA parameters were derived using Pearson's correlation coefficient. Predicted values were generated for MMTT ISR and compared to GPA parameters using Bland Altman analysis to assess degree of concordance. Results: 85 PwCF (45 female; 75 PI-CF and 10 PS-CF) median (range) age 23 (6-56) years with BMI 23 (13-34) kg/m2, HbA1c 5.5 (3.8-10.2)%, and FEV1%-predicted 88 (26-125) and 4 non-CF controls of similar age and BMI were included. ISR AUC30min positively correlated with AIRarg (r=0.55), AIRpot (r=0.62), and AIRmax (r=0.46) and with ACRarg (r=0.59), ACRpot (r=0.60), and ACRmax (r=0.51) (all P<0.001). ISR AUC30min strongly predicted AIRarg (concordance=0.86), AIRpot (concordance=0.89), and AIRmax (concordance=0.76) at lower mean GPA values, but underestimated AIRarg, AIRpot, and AIRmax at higher GPA-defined ß-cell secretory capacity. Between test agreement was unaltered by adjustment for study group, OGTT glucose category, and BMI. Conclusion: Early-phase insulin secretion during MMTT can accurately predict GPA-derived measures of ß-cell function and secretory capacity when functional ß-cell mass is reduced. These data can inform future multicenter studies requiring reliable, standardized, and technically feasible testing mechanisms to quantify ß-cell function and secretory capacity.

Transient albuminuria in the setting of short-term severe hyperglycemia in type 1 diabetes.

In a cohort of 1817 children with type 1 diabetes (T1D), short-term hyperglycemia was associated with transient albuminuria (11 % during new-onset T1D without diabetic ketoacidosis (DKA), 12 % during/after DKA, 6 % during routine screening). Our findings have implications regarding future risk of diabetic kidney disease and further investigation is needed.

Approach to the Patient: Central Precocious Puberty.

Central precocious puberty (CPP) classically refers to premature activation of the hypothalamic-pituitary-gonadal axis with onset of sexual development before the age of 8 years in girls and 9 years in boys. A decrease in the age of thelarche has been reported over the past several decades; however, the tempo of pubertal progression can be slower and adult height may not be adversely affected in many of the girls who experience thelarche at 6-8 years. Outside of this secular trend in the development itself, the past several decades have also brought about advances in diagnosis and management. This includes the widespread use of an ultrasensitive luteinizing hormone assay, decreasing the need for stimulation testing and a better understanding of the genetics that govern the onset of puberty. Additionally, management of CPP using gonadotropin-releasing hormone analogs (GnRHas) has changed with the advent of new longer-acting formulations. Emerging long-term outcomes of GnRHa administration with regards to obesity, cardiovascular risk factors and fertility are reassuring. Despite these advancements, clinical care in CPP is hampered by the lack of well-designed controlled studies, and management decisions are frequently not supported by clear practice guidelines. Data in boys with CPP are limited and this article focuses on the diagnosis and management of CPP in girls, particularly, in those who present with thelarche at the age of 6-8 years.

Bone metabolism and incretin hormones following glucose ingestion in young adults with pancreatic insufficient cystic fibrosis.

Background: Gut-derived incretin hormones, including glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide 1 (GLP-1), regulate post-prandial glucose metabolism by promoting insulin production. GIP, GLP-1, and insulin contribute to the acute bone anti-resorptive effect of macronutrient ingestion by modifying bone turnover. Cystic fibrosis (CF) is associated with exocrine pancreatic insufficiency (PI), which perturbs the incretin response. Cross-talk between the gut and bone ("gut-bone axis") has not yet been studied in PI-CF. The objectives of this study were to assess changes in biomarkers of bone metabolism during oral glucose tolerance testing (OGTT) and to test associations between incretins and biomarkers of bone metabolism in individuals with PI-CF. Methods: We performed a secondary analysis of previously acquired blood specimens from multi-sample OGTT from individuals with PI-CF ages 14-30 years (n = 23). Changes in insulin, incretins, and biomarkers of bone resorption (C-terminal telopeptide of type 1 collagen [CTX]) and formation (procollagen type I N-terminal propeptide [P1NP]) during OGTT were computed. Results: CTX decreased by 32% by min 120 of OGTT (P < 0.001), but P1NP was unchanged. Increases in GIP from 0 to 30 mins (rho = -0.48, P = 0.03) and decreases in GIP from 30 to 120 mins (rho = 0.62, P = 0.002) correlated with decreases in CTX from mins 0-120. Changes in GLP-1 and insulin were not correlated with changes in CTX, and changes in incretins and insulin were not correlated with changes in P1NP. Conclusions: Intact GIP response was correlated with the bone anti-resorptive effect of glucose ingestion, represented by a decrease in CTX. Since incretin hormones might contribute to development of diabetes and bone disease in CF, the "gut-bone axis" warrants further attention in CF during the years surrounding peak bone mass attainment.

Perceptions of Diabetes Technology Use in Cystic Fibrosis-Related Diabetes Management.

Background: Diabetes technologies are associated with improvements in glycemic control and health-related quality of life among people with type 1 diabetes (T1D). Use and perceptions of continuous glucose monitors (CGM) and insulin pumps within the cystic fibrosis (CF) community have not been well studied. Methods: A 30-item online survey addressing cystic fibrosis-related diabetes (CFRD) diagnosis, CGM and insulin pump use, and perceptions of diabetes technologies was sent to a CF community group, including people with CF (pwCF) and parents of children with CF (cwCF). Results: The response rate was 11% (n = 120; 83 pwCF, 35 cwCF). Sixty-one percent of pwCF and 34% of cwCF reported a diagnosis of CFRD. CGM use was reported by 75% (n = 47) of respondents with CFRD but was discontinued by 19% (n = 9), most commonly due to cost and increased worry about glycemia. Insulin pump therapy was reported by 29% (n = 18 of 62) of respondents with CFRD and was discontinued by 28% (n = 5), most commonly due to pain or skin irritation. Overall, 91% agreed or strongly agreed that CGM facilitated CFRD management. Eighty-one percent agreed with at least five of seven positive statements about CGM as compared with 22% for insulin pumps. Potential embarrassment over device wear, concerns about cost, and pain were commonly held negative perceptions of both technologies. Conclusions: As compared with T1D and despite perceived benefits, rates of sustained diabetes technology use are low in the CFRD community. Better insurance coverage to mitigate cost, better patient education, and confirmation that these technologies improve health and patient-reported outcomes may increase uptake.

Dysregulated insulin in pancreatic insufficient cystic fibrosis with post-prandial hypoglycemia.

BACKGROUND: Post-prandial and oral glucose tolerance test-related hypoglycemia is common in cystic fibrosis (CF); however, the underlying mechanisms are unclear. METHODS: To understand the relationship of hypoglycemia with meal-related glucose excursion and insulin secretion, we analyzed plasma glucose, insulin, C-peptide, glucagon and incretins obtained during standardized mixed-meal tolerance tests (MMTT) in non-diabetic adolescents and young adults with pancreatic insufficient CF (PI-CF). RESULTS: Hypoglycemia, defined as glucose <70 mg/dL, occurred in 9/34 subjects at 150 (range:120-210) minutes following initial meal ingestion. Hypoglycemia[+] and hypoglycemia[-] groups did not differ in gender, age, lung function, HbA1c, or BMI. While 11/14 hypoglycemia[-] individuals displayed normal glucose tolerance (NGT), only 2/9 hypoglycemia[+] had NGT. Peak glucose was higher in hypoglycemia[+] vs hypoglycemia[-]. Compared to hypoglycemia[-] NGT, hypoglycemia[+] exhibited lower early-phase insulin secretion (ISR-AUC0-30min). ISR-AUC120-180min was not different in hypoglycemia[+] vs hypoglycemia[-] with abnormal glucose tolerance (AGT); however, glucose-AUC120-180min was lower in hypoglycemia[+] vs hypoglycemia[-] AGT. After adjusting for glucose-AUC, hypoglycemia[+] subjects tended to have higher ISR-AUC120-180min than hypoglycemia[-] AGT. Glucagon concentration did not differ between groups. Lower GLP-1-AUC30min and AUC180min and higher GIP-AUC30min were present in hypoglycemia[+] individuals. CONCLUSION: Hypoglycemia is common in PI-CF following MMTT and is associated with early glucose dysregulation (higher peak glucose), more impaired early-phase insulin secretion (lower ISR-AUC30min), and possibly late compensatory hyperinsulinemia. Further study is required to understand whether absence of glucagon difference in the hypoglycemia[+] individuals signals counterregulatory impairment, to delineate the role of incretins in hypoglycemia, and to determine the relationship of hypoglycemia to emergence of CFRD.

Hypoglycemia and Islet Dysfunction Following Oral Glucose Tolerance Testing in Pancreatic-Insufficient Cystic Fibrosis.

CONTEXT: Oral glucose tolerance test (OGTT)-related hypoglycemia is common in pancreatic-insufficient cystic fibrosis (PI-CF), but its mechanistic underpinnings are yet to be established. OBJECTIVE: To delineate the mechanism(s) underlying OGTT-related hypoglycemia. DESIGN AND SETTING: We performed 180-minute OGTTs with frequent blood sampling in adolescents and young adults with PI-CF and compared results with those from a historical healthy control group. Hypoglycemia (Hypo[+]) was defined as plasma glucose <65 mg/dL. We hypothesized that CF-Hypo[+] would demonstrate impaired early phase insulin secretion and persistent late insulin effect compared with control-Hypo[+], and explored the contextual counterregulatory response. MAIN OUTCOME MEASURE: OGTT 1-hour and nadir glucose, insulin, C-peptide, and insulin secretory rate (ISR) incremental areas under the curve (AUC) between 0 and 30 minutes (early) and between 120 and 180 minutes (late), and Δglucagon120-180min and Δfree fatty acids (FFAs)120-180min were compared between individuals with CF and control participants with Hypo[+]. RESULTS: Hypoglycemia occurred in 15/23 (65%) patients with CF (43% female, aged 24.8 [14.6-30.6] years) and 8/15 (55%) control participants (33% female, aged 26 [21-38] years). The CF-Hypo[+] group versus the control-Hypo[+] group had higher 1-hour glucose (197 ± 49 vs 139 ± 53 mg/dL; P = 0.05) and lower nadir glucose levels (48 ± 7 vs 59 ± 4 mg/dL; P < 0.01), while insulin, C-peptide, and ISR-AUC0-30 min results were lower and insulin and C-peptide, and AUC120-180min results were higher (P < 0.05). Individuals with CF-Hypo[+] had lower Δglucagon120-180min and ΔFFA120-180min compared with the control-Hypo[+] group (P < 0.01). CONCLUSIONS: OGTT-related hypoglycemia in PI-CF is associated with elevated 1-hour glucose, impaired early phase insulin secretion, higher late insulin exposure, and less increase in glucagon and FFAs. These data suggest that hypoglycemia in CF is a manifestation of islet dysfunction including an impaired counterregulatory response.