Early exposures and inherent factors in premature newborns are associated with type 1 diabetes.

BACKGROUND: Pathophysiology of type 1 diabetes (T1D) involves immune responses that may be associated with early exposure to environmental factors among preterm newborns. The aim of this work was to evaluate for association between T1D and maternal, nutritional, and medical exposures during the neonatal period among premature newborns. METHODS: This is a multicenter, matched case-control study. Preterm newborns, who developed T1D before 18 years, were matched by sex, gestational age (GA), birth date, and medical center of birth with newborns who did not develop TID. Data included maternal medical history, birth weight (BW), length of hospitalization, enteral and parenteral medications, fluid administration, and feeding modalities during hospitalization. RESULTS: Fifty-two patients with T1D, 26 males, median age at T1D diagnosis 8.17 years (5.92-9.77), median GA 34 weeks (33-m36), and 132 matched controls, were included. Multivariate-conditional-regression demonstrated a significant association between T1D and any maternal illness (23.1% vs. 9.1%, OR = 4.99 (1.69-14.72), p = 0.004), higher BW-SDS (0.07 ± 0.95 vs. -0.27 ± 0.97, OR = 2.03 (1.19-3.49), p = 0.01), longer duration of glucose infusion (3 (1-5) days vs. 2 (0-4), OR = 1.23 (1.03-1.46), p = 0.02), and antibiotic therapy beyond the first week of life (19.2% vs. 6.9%, OR = 5.22 (1.32-20.70), p = 0.019). Antibiotic treatment during the first week of life was negatively associated with T1D (51.9% vs. 67.2%, OR 0.31 (0.11-0.88), p = 0.027). CONCLUSIONS: A novel association was demonstrated between the development of T1D and early interventions and exposures among preterm newborns. IMPACT: Type 1 diabetes mellitus during childhood may be associated with early exposures during the neonatal period, in addition to known maternal and neonatal metabolic parameters. Early exposure to intravenous antibiotics, differing between the first week of life and later, and longer parenteral glucose administration to preterm newborns were associated with childhood type 1 diabetes. This is in addition to familiar maternal risk factors. Future prospective studies should examine the microbial changes and immune system characteristics of preterm and term neonates exposed to parenteral antibiotics and glucose treatment, in order to validate our exploratory findings.

Youth-onset type 2 diabetes in Israel: A national cohort.

BACKGROUND: Prevalence of youth-onset type 2 diabetes (T2D) has increased worldwide, paralleling the rise in pediatric obesity. Occurrence and clinical manifestations vary regionally and demographically. OBJECTIVES: We assessed the incidence, and clinical and demographic manifestations of youth-onset T2D in Israel. METHODS: In a national observational study, demographic, clinical, and laboratory data were collected from the medical records of children and adolescents, aged 10-18 years, diagnosed with T2D between the years 2008 and 2019. RESULTS: The incidence of youth-onset T2D in Israel increased significantly from 0.63/100,000 in 2008 to 3.41/100,000 in 2019. The study cohort comprised 379 individuals (228 girls [59.7%], 221 Jews [58.3%], mean age 14.7 ± 1.9 years); 73.1% had a positive family history of T2D. Mean body mass index (BMI) z-score was 1.96 ± 0.7, higher in Jews than Arabs. High systolic (≥ 130 mmHg) and diastolic blood pressure (≥ 85 mmHg) were observed in 33.7% and 7.8% of patients, respectively; mean glycosylated hemoglobin (A1c) level at diagnosis was 8.8 ± 2.5%. Dyslipidemia, with high triglyceride (>150 mg/dl) and low HDL-c (<40 mg/dl) levels, was found in 45.6% and 56.5%, respectively. Microalbuminuria and retinopathy were documented at diagnosis, 15.2% and 1.9%, respectively) and increased (36.7% and 4.6%, respectively) at follow-up of 2.9 ± 2.1 years. Criteria of metabolic syndrome were met by 224 (62.2%) patients, and fatty liver documented in 65%, mainly Jews. Psychosocial comorbidity was found in 31%. Treatment with metformin (45.6%), insulin (20.6%), and lifestyle modification (18%) improved glycemic control. CONCLUSION: Youth-onset T2D in Israel has increased significantly and presents a unique profile.

Analysis of the genetic basis of height in large Jewish nuclear families.

Despite intensive study, most of the specific genetic factors that contribute to variation in human height remain undiscovered. We conducted a family-based linkage study of height in a unique cohort of very large nuclear families from a founder (Jewish) population. This design allowed for increased power to detect linkage, compared to previous family-based studies. Loci we identified in discovery families could explain an estimated lower bound of 6% of the variance in height in validation families. We showed that these loci are not tagging known common variants associated with height. Rather, we suggest that the observed signals arise from variants with large effects that are rare globally but elevated in frequency in the Jewish population.

Essential Role of BRCA2 in Ovarian Development and Function.

The causes of ovarian dysgenesis remain incompletely understood. Two sisters with XX ovarian dysgenesis carried compound heterozygous truncating mutations in the BRCA2 gene that led to reduced BRCA2 protein levels and an impaired response to DNA damage, which resulted in chromosomal breakage and the failure of RAD51 to be recruited to double-stranded DNA breaks. The sisters also had microcephaly, and one sister was in long-term remission from leukemia, which had been diagnosed when she was 5 years old. Drosophila mutants that were null for an orthologue of BRCA2 were sterile, and gonadal dysgenesis was present in both sexes. These results revealed a new role for BRCA2 and highlight the importance to ovarian development of genes that are critical for recombination during meiosis. (Funded by the Israel Science Foundation and others.).

Eligibility for growth hormone therapy in children born small for gestational age is substantially lower than expected.

BACKGROUND: Growth hormone therapy is indicated for children who are both born 'small for gestational age' (SGA) and do not achieve adequate catch-up growth (ACUG). OBJECTIVE: To evaluate the actual incidence of infants born SGA and their actual ACUG. METHODS: Birth weight data from the newborn registry at two hospitals were analysed during four consecutive years. SGA was defined according to WHO parameters and the corresponding Israeli criteria. Follow-up measurements of height and weight were abstracted from either the Ministry of Health-child growth follow-up centres, or their paediatrician clinic. ACUG was declared when the height reached was above -2.5 or -2 standard deviations (SDS) from the mean for age and gender. RESULTS: Out of 43 307, only 524 babies in the cohort (1.2%) were SGA (52% of expected). This finding was consistent annually. Out of the 446 SGA born children with available growth data (85%) during 4-8 years, 405 children (90.8%) reached a height greater than -2SDS and 428 (96%!) reached a height greater than -2.5 SDS. Term children had higher rate of ACUG achievement as compared to preterm 97.2% vs 86.8% (P < .001). Birth week and birth weight were also related to achievement of ACUG (P < .001). CONCLUSION: This large representative, heterogeneous and Western Caucasian cohort indicates that the actual number of SGA newborns is nearly half of the expected and that the actual prevalence of ACUG is also significantly higher than previously reported. These findings may have an impact on morbidity, health cost planning and growth hormone requirements in SGA babies.

Aldosterone synthase (CYP11B2) deficiency among Palestinian infants: Three novel variants and genetic heterogeneity.

Aldosterone synthase deficiency (ASD) is a rare potentially life-threatening genetic disorder that usually presents during infancy due to pathogenic variants in the CYP11B2 gene. Knowledge about CYP11B2 variants in the Arab population is scarce. Here, we present and analyze five Palestinian patients and their different novel pathogenic variants. Data on clinical presentation, electrolytes, plasma renin activity, and steroid hormone levels of five patients diagnosed with ASD were summarized. Sequencing of the CYP11B2 gene exons was followed by evolutionary conservation analysis and structural modeling of the variants. All patients were from highly consanguineous Palestinian families. The patients presented at 1-4 months of age with recurrent vomiting, poor weight gain, hyponatremia, hyperkalemia, and low aldosterone levels. Genetic analysis of the CYP11B2 gene revealed three homozygous pathogenic variants: p.Ser344Profs*9, p.G452W in two patients from an extended family, and p.Q338stop. A previously described pathogenic variant was found in one patient: p.G288S. We described four different CYP11B2 gene pathogenic variants in a relatively small population. Our findings may contribute to the future early diagnosis and therapy for patients with ASD among Arab patients who present with failure to thrive and compatible electrolyte disturbances.

Birth during the moderate weather seasons is associated with early onset of type 1 diabetes in the Mediterranean area.

AIM: To assess the association of seasonal and perinatal parameters with early age of type 1 diabetes (T1D) onset. METHODS: A cross-sectional review of all medical records of T1D patients born between the years 1990 and 2005, and diagnosed before/by the age of 10 years, from 13 university-affiliated paediatric medical centres in Israel, was performed. Data included: gender, ethnicity, seasons of birth and disease onset, birth gestational age and weight, and autoimmune diseases of the probands and their first-degree family members. Statistical analysis included the Chi-square test or Mann-Whitney test, as appropriate and multivariate regression analysis. RESULTS: Enrolled were 1571 T1D patients at a median age of T1D onset 6.9 years (IQR 4.4,8.4); 336 of them presented before 4 years of age. The median age of this group was 2.5 years (IQR 1.7,3.2), and of the 1235 patients who presented after 4 years of age, median presentation age was 7.5 years (IQR 6.1,8.8). Multivariate regression analysis demonstrated that a more recent birth year; OR = 1.06, 95% CI 1.02-1.1, P = 0.003, and birth during the moderate weather months (September, October, March, and April) were significantly associated with younger age at T1D onset; OR = 1.68, 95% CI 1.17-2.4, P = 0.005. CONCLUSIONS: Our novel finding demonstrates the association between younger than 4 years old age at presentation and birth during moderate weather months. The results also support previous reports, that there is a slight increase in the annual incidence of T1D in the youngest age groups.

The novel R211Q POP1 homozygous mutation causes different pathogenesis and skeletal changes from those of previously reported POP1-associated anauxetic dysplasia.

Processing of Precursor RNA 1 (POP1) is a core protein component shared by two essential closely related eukaryotic ribonucleoprotein complexes: RNase MRP (the mitochondrial RNA processing ribonuclease) and RNase P. Recently, five patients harboring mutations in POP1 have been reported with severe spondylo-epi-metaphyseal dysplasia and extremely short stature. We report a unique clinical phenotype resulting from the novel homozygous R211Q POP1 mutation in three patients from one family, presenting with severe short stature but only subtle skeletal dysplastic changes that are merely metaphyseal. The RNA moiety of the RNase-MRP complex quantified in RNA extracted from peripheral lymphocytes was dramatically reduced in affected patients indicating instability of the enzymatic complex. However, pre5.8s rRNA, a substrate of RNase-MRP complex, was not accumulated in patients' RNA unlike in the previously reported POP1 mutations; this may explain the uniquely mild phenotype in our cases, and questions the assumption that alteration in ribosomal biogenesis is the pathophysiological basis for skeletal disorders caused by POP1 mutations. Finally, POP1 mutations should be considered in familial cases with severe short stature even when skeletal dysplasia is not strongly evident.

A Unique Presentation of XY Gonadal Dysgenesis in Frasier Syndrome due to WT1 Mutation and a Literature Review.

Frasier syndrome (FS), a rare disease caused by inherited or de novo mutation in Wilm's Tumor suppressor gene 1 (WT1), is characterized by slow progressive nephropathy, XY gonadal dysgenesis (XY-DSD), and increased risk for gonadal tumors. Early childhood (1-6 years) nephropathy progresses with age to refractory nephrotic syndrome, and end-stage renal failure in late adolescence, when delayed puberty and/or primary amenorrhea are clinically evident. We report a unique case of FS presenting initially with primary amenorrhea at 16 years, without previous or concomitant renal damage. Only subsequently she developed an extremely late-onset nephropathy. Genetic analysis revealed the IVS9 + 5 G>A mutation in intron 9 of the WT1 gene. This clinical presentation and review of WT1 literature highlights the importance of considering FS in the differential diagnosis of patients with 46,XY disorders of Sexual development, even without nephropathy. Furthermore, the identification WT1 gene mutation prior to evident renal dysfunction indicates an immediate and close surveillance of renal function enabling an optimal and timely medical response.

Haploseek: a 24-hour all-in-one method for preimplantation genetic diagnosis (PGD) of monogenic disease and aneuploidy.

PURPOSE: To develop an economical, user-friendly, and accurate all-in-one next-generation sequencing (NGS)-based workflow for single-cell gene variant detection combined with comprehensive chromosome screening in a 24-hour workflow protocol. METHODS: We subjected single lymphoblast cells or blastomere/blastocyst biopsies from four different families to low coverage (0.3×-1.4×) genome sequencing. We combined copy-number variant (CNV) detection and whole-genome haplotype phase prediction via Haploseek, a novel, user-friendly analysis pipeline. We validated haplotype predictions for each sample by comparing with clinical preimplantation genetic diagnosis (PGD) case results or by single-nucleotide polymorphism (SNP) microarray analysis of bulk DNA from each respective lymphoblast culture donor. CNV predictions were validated by established commercial kits for single-cell CNV prediction. RESULTS: Haplotype phasing of the single lymphoblast/embryo biopsy sequencing data was highly concordant with relevant ground truth haplotypes in all samples/biopsies from all four families. In addition, whole-genome copy-number assessments were concordant with the results of a commercial kit. CONCLUSION: Our results demonstrate the establishment of a reliable method for all-in-one molecular and chromosomal diagnosis of single cells. Important features of the Haploseek pipeline include rapid sample processing, rapid sequencing, streamlined analysis, and user-friendly reporting, so as to expedite clinical PGD implementation.

Prevalence of early and late prematurity is similar among pediatric type 1 diabetes patients and the general population.

BACKGROUND: The incidence of type 1 diabetes mellitus (T1DM) has increased in recent decades, as has the incidence of preterm births (<37 weeks). We aimed to evaluate and compare the prevalence of prematurity and early prematurity (<34 weeks) and birth season variability among T1DM and non-T1DM children. METHODS: A nationwide cross-sectional study was conducted, with linkage of data from 13 paediatric diabetes centers and Israeli National Registries, including T1DM patients and general non-T1DM population, born during 2000 to 2013. Gathered data included ethnicity, gender, birth week, weight, and season. The prevalence of prematurity and birth season were compared with the general population birth registry using Pearson Chi-square test. RESULTS: The study population included 1452 T1DM patients, 52.7% males, and 2 138 668 subjects in the general non-T1DM population, 51.2% males. The prevalence of late and early prematurity was similar between groups (6.1% and 2.2% in the T1DM group vs 5.6% and 2.0% in the general non-T1DM group, P = 0.25 and P = 0.38, respectively). OR for prematurity among T1DM patients was 1.15 (0.95-1.39), P = 0.16. No difference in birth season was demonstrated between preterm and term, in T1DM and general non-T1DM populations. Ethiopian descent was more prevalent among T1DM patients compared with the non-T1DM population, in both term and preterm born. CONCLUSIONS: This is the largest population-based study, and the first in the Middle East geographical area, indicating that prematurity, including early prematurity, is not associated with T1DM during childhood. The study was registered at https://clinicaltrials.gov/: NCT02929953.

Combined mineralocorticoid and glucocorticoid deficiency is caused by a novel founder nicotinamide nucleotide transhydrogenase mutation that alters mitochondrial morphology and increases oxidative stress.

BACKGROUND: Familial glucocorticoid deficiency (FGD) reflects specific failure of adrenocortical glucocorticoid production in response to adrenocorticotropic hormone (ACTH). Most cases are caused by mutations encoding ACTH-receptor components (MC2R, MRAP) or the general steroidogenesis protein (StAR). Recently, nicotinamide nucleotide transhydrogenase (NNT) mutations were found to cause FGD through a postulated mechanism resulting from decreased detoxification of reactive oxygen species (ROS) in adrenocortical cells. METHODS AND RESULTS: In a consanguineous Palestinian family with combined mineralocorticoid and glucocorticoid deficiency, whole-exome sequencing revealed a novel homozygous NNT_c.598 G>A, p.G200S, mutation. Another affected, unrelated Palestinian child was also homozygous for NNT_p.G200S. Haplotype analysis showed this mutation is ancestral; carrier frequency in ethnically matched controls is 1/200. Assessment of patient fibroblasts for ROS production, ATP content and mitochondrial morphology showed that biallelic NNT mutations result in increased levels of ROS, lower ATP content and morphological mitochondrial defects. CONCLUSIONS: This report of a novel NNT mutation, p.G200S, expands the phenotype of NNT mutations to include mineralocorticoid deficiency. We provide the first patient-based evidence that NNT mutations can cause oxidative stress and both phenotypic and functional mitochondrial defects. These results directly demonstrate the importance of NNT to mitochondrial function in the setting of adrenocortical insufficiency.

Minichromosome maintenance complex component 8 (MCM8) gene mutations result in primary gonadal failure.

BACKGROUND: Primary gonadal failure is characterised by primary amenorrhoea or early menopause in females, and oligospermia or azoospermia in males. Variants of the minichromosome maintenance complex component 8 gene (MCM8) have recently been shown to be significantly associated with women's menopausal age in genome-wide association studies. Furthermore, MCM8-knockout mice are sterile. The objective of this study was to elucidate the genetic aetiology of gonadal failure in two consanguineous families presenting as primary amenorrhoea in the females and as small testes and azoospermia in a male. METHODS AND RESULTS: Using whole exome sequencing, we identified two novel homozygous mutations in the MCM8 gene: a splice (c.1954-1G>A) and a frameshift (c.1469-1470insTA). In each consanguineous family the mutation segregated with the disease and both mutations were absent in 100 ethnically matched controls. The splice mutation led to lack of the wild-type transcript and three different aberrant transcripts predicted to result in either truncated or significantly shorter proteins. Quantitative analysis of the aberrantly spliced transcripts showed a significant decrease in total MCM8 message in affected homozygotes for the mutation, and an intermediate decrease in heterozygous family members. Chromosomal breakage following exposure to mitomcyin C was significantly increased in cells from homozygous individuals for c.1954-1G>A, as well as c.1469-1470insTA. CONCLUSIONS: MCM8, a component of the pre-replication complex, is crucial for gonadal development and maintenance in humans-both males and females. These findings provide new insights into the genetic disorders of infertility and premature menopause in women.

XX ovarian dysgenesis is caused by a PSMC3IP/HOP2 mutation that abolishes coactivation of estrogen-driven transcription.

XX female gonadal dysgenesis (XX-GD) is a rare, genetically heterogeneous disorder characterized by lack of spontaneous pubertal development, primary amenorrhea, uterine hypoplasia, and hypergonadotropic hypogonadism as a result of streak gonads. Most cases are unexplained but thought to be autosomal recessive. We elucidated the genetic basis of XX-GD in a highly consanguineous Palestinian family by using homozygosity mapping and candidate-gene and whole-exome sequencing. Affected females were homozygous for a 3 bp deletion (NM_016556.2, c.600_602del) in the PSMC3IP gene, leading to deletion of a glutamic acid residue (p.Glu201del) in the highly conserved C-terminal acidic domain. Proteasome 26S subunit, ATPase, 3-Interacting Protein (PSMC3IP)/Tat Binding Protein Interacting Protein (TBPIP) is a nuclear, tissue-specific protein with multiple functions. It is critical for meiotic recombination as indicated by the known role of its yeast ortholog, Hop2. Through the C terminus (not present in yeast), PSMC3IP also coactivates ligand-driven transcription mediated by estrogen, androgen, glucocorticoid, progesterone, and thyroid nuclear receptors. In cell lines, the p.Glu201del mutation abolished PSMC3IP activation of estrogen-driven transcription. Impaired estrogenic signaling can lead to ovarian dysgenesis both by affecting the size of the follicular pool created during fetal development and by failing to counteract follicular atresia during puberty. PSMC3IP joins previous genes known to be mutated in XX-GD, the FSH receptor, and BMP15, highlighting the importance of hormonal signaling in ovarian development and maintenance and suggesting a common pathway perturbed in isolated XX-GD. By analogy to other XX-GD genes, PSMC3IP is also a candidate gene for premature ovarian failure, and its role in folliculogenesis should be further investigated.

Long-term therapy with CFTR modulators consistently improves glucose metabolism in adolescents and adults with cystic fibrosis.

BACKGROUND: Impaired glycemic control and the subsequent development of Cystic fibrosis Related Diabetes (CFRD) are prevalent complications, affecting up to 50 % of adults with cystic fibrosis (CF). CFTR modulator (CFTRm) therapies improve pulmonary functions, reduce exacerbation rates, increase survival in people with CF (pwCF) and appear to have a positive effect on extrapulmonary manifestations, such as nutritional state, improvements in upper respiratory symptoms, and quality of life. Initial findings indicate that CFTRm may have a positive impact on short-term glycemic control; however, long-term effects remain uncertain at present. METHODS: In this retrospective study, data were collected and analyzed on 15 pwCF, ages 13-37 years, started on CFTRm therapy. Oral Glucose Tolerance Test (OGTT) results were compared pre- and post-CFTRm therapy. RESULTS: The 120-min OGTT value decreased from 159.7 mg/dL to 130.4 mg/dL post-CFTRm (p = 0.047). The average time elapsed between the two OGTTs was 49.87 months (ranging 9-157 months, median 38 months). Glycemic status improved in six pwCF (two CFRD to normal (NGT)/indeterminate (INDET) glucose tolerance; two impaired glucose tolerance (IGT) to INDET; two INDET to NGT) and worsened in one (IGT to CFRD). Six pwCF and NGT remained stable with no changes in glycemic status throughout the follow-up period. CONCLUSIONS: CFTRm therapy may decelerate the glycemic control deterioration in pwCF over an extended period. These findings indicate the need for periodic OGTTs following the initiation of CFTRm therapy to appropriately adjust insulin requirements and prevent hypoglycemia. Further larger cohorts are required to authenticate and substantiate these findings.

Dasiglucagon for the Treatment of Congenital Hyperinsulinism: A Randomized Phase 3 Trial in Infants and Children.

CONTEXT: Congenital hyperinsulinism (CHI) is characterized by dysregulated insulin secretion causing hypoglycemia and consequent brain damage. Dasiglucagon is a glucagon analogue under investigation to treat CHI. OBJECTIVE: To evaluate the efficacy and safety of dasiglucagon delivered via continuous subcutaneous infusion to children with CHI and persistent hypoglycemia as add-on to standard of care (SoC). METHODS: In this open-label trial, patients were randomized 1:1 to SoC or SoC + dasiglucagon (10-70 µg/h) for 4 weeks. In the following 4 weeks, all patients received dasiglucagon + SoC. Hypoglycemia was assessed by self-monitored plasma glucose (SMPG) and blinded continuous glucose monitoring (CGM). Primary endpoint was average number of SMPG-detected hypoglycemia episodes/week (SMPG <3.9 mmol/L) during Weeks 2 to 4. RESULTS: Thirty-two patients (0.6-10.9 years) were randomly assigned to dasiglucagon + SoC (n = 16) or SoC (n = 16). The rate of SMPG-detected hypoglycemia decreased from baseline in both groups, but with no statistically significant difference during Weeks 2 to 4 (event rate ratio: 0.85 [0.54; 1.36], P = .5028). However, dasiglucagon administration resulted in a 43% reduction in CGM-detected hypoglycemia (<3.9 mmol/L) vs SoC alone during Weeks 2 to 4 (post hoc analysis; event rate ratio: 0.57 [0.39; 0.83], P = .0029). Dasiglucagon enabled reductions (of 37% to 61%) in all other measures of hypoglycemia assessed by CGM vs SoC alone including extent and percent time in hypoglycemia (post hoc analyses). Dasiglucagon appeared safe and well tolerated. Skin and gastrointestinal events were more frequent with dasiglucagon + SoC than SoC only. CONCLUSION: Clinically meaningful reductions in all CGM-recorded measures of hypoglycemia support using dasiglucagon as a potential treatment for CHI.

Spleen function is reduced in individuals with NR5A1 variants with or without a difference of sex development: a cross-sectional study.

OBJECTIVE: NR5A1 is a key regulator of sex differentiation and has been implicated in spleen development through transcription activation of TLX1. Concerns exist about hypo- or asplenism in individuals who have a difference of sex development (DSD) due to an NR5A1 disease-causing variant. We aimed to assess spleen anatomy and function in a clinical cohort of such individuals and in their asymptomatic family member carriers. DESIGN: Cross-sectional assessment in 22 patients with a DSD or primary ovarian insufficiency and 5 asymptomatic carriers from 18 families, harboring 14 different NR5A1 variants. METHODS: Spleen anatomy was assessed by ultrasound, spleen function by peripheral blood cell count, white blood cell differentiation, percentage of nonswitched memory B cells, specific pneumococcal antibody response, % pitted red blood cells, and Howell-Jolly bodies. RESULTS: Patients and asymptomatic heterozygous individuals had significantly decreased nonswitched memory B cells compared to healthy controls, but higher than asplenic patients. Thrombocytosis and spleen hypoplasia were present in 50% of heterozygous individuals. Four out of 5 individuals homozygous for the previously described p.(Arg103Gln) variant had asplenia. CONCLUSIONS: Individuals harboring a heterozygous NR5A1 variant that may cause DSD have a considerable risk for functional hyposplenism, irrespective of their gonadal phenotype. Splenic function should be assessed in these individuals, and if affected or unknown, prophylaxis is recommended to prevent invasive encapsulated bacterial infections. The splenic phenotype associated with NR5A1 variants is more severe in homozygous individuals and is, at least for the p.(Arg103Gln) variant, associated with asplenism.