Testicular Dysfunction in 47,XXY Boys: When It All Begins. A Semilongitudinal Study.

OBJECTIVE: Klinefelter syndrome is the most common chromosomal disorder in males and the most common cause of hypergonadotropic hypogonadism. We describe the natural history of testicular dysfunction in patients with Klinefelter syndrome through the integration of clinical, hormonal, and quantitative ultrasound data in a life-course perspective. DESIGN: Prospective semilongitudinal study. METHODS: We included 155 subjects with 47,XXY karyotype (age range: 7 months-55 years) naïve to testosterone replacement therapy. Subjects were divided according to pubertal stage and age group (transition age and adults). Serial clinical, hormonal, and testicular ultrasound (US) assessments were performed. RESULTS: Testicular development progresses until Tanner stage 4, with subsequent regression, whereas Sertoli and germ cell impairment is not hormonally detected before Tanner stages 3-4, as reflected by normal inhibin B values until stage 4 and the fall in the inhibin B/follicle-stimulating hormone ratio thereafter. The testosterone/luteinizing hormone ratio peaks during Tanner stages 2-3 and declines from Tanner stage 4 onward, preceding the development of overt hypogonadism. US echotexture progressively worsens until transition age, reflecting ongoing gonadal compromise, whereas quantitative US echotexture measures and the presence of both hypoechoic lesions and microlithiasis independently and significantly predict a lower circulating testosterone level. CONCLUSIONS: The findings from this large prospective study contribute to our understanding of the natural history of testicular dysfunction in Klinefelter syndrome, underlining the importance of quantitative testicular US in infancy and childhood, as well as during pubertal development and transition age, for the optimal care of Klinefelter syndrome patients.

Serum prokineticin-2 in prepubertal and adult Klinefelter individuals.

The prokineticin-2 (PROK2) is a small peptide belonging to the prokineticin family. In humans and rodents this chemokine is primarily involved in the control of central and peripheral reproductive processes. Klinefelter's syndrome (KS) is the first cause of male genetic infertility, due to an extra X chromosome, which may occur with a classical karyotype (47, XXY) or mosaic forms (46, XY/47, XXY). In affected subjects, pubertal maturation usually begins at an adequate chronological age, but when development is almost complete, they display a primary gonadal failure, with early spermatogenesis damage, and later onset of testosterone insufficiency. Thus, the main aim of the present study was to investigate the serum levels of PROK2 in prepubertal and adult KS patients, comparing them with healthy subjects. We showed for the first time the presence of PROK2 in the children serum but with significant changes in KS individuals. Indeed, compared with healthy subjects characterized by PROK2 serum elevation during the growth, KS individuals showed constant serum levels during the sexual maturation phase (higher during the prepubertal phase but lower during the adult age). In conclusion, these data indicate that in KS individuals PROK2 may be considered a biomarker for investigating the SK infertility process.

Non-organ-specific autoimmunity in adult 47,XXY Klinefelter patients and higher-grade X-chromosome aneuploidies.

Current literature regarding systemic autoimmune diseases in X-chromosome aneuploidies is scarce and limited to case reports. Our aim was to evaluate the frequency of anti-nuclear (ANAs), extractable nuclear (ENA), anti-double-stranded DNA (dsDNAs), anti-smooth muscle (ASMAs) and anti-mitochondrial (AMAs) antibodies in a large cohort of adults with Klinefelter's syndrome (KS, 47,XXY) and rare higher-grade sex chromosome aneuploidies (HGAs) for the first time. Sera from 138 X-chromosome aneuploid patients [124 adult patients with 47,XXY KS and 14 patients with HGA (six children, eight adults)] and 50 age-matched 46,XY controls were recruited from the Sapienza University of Rome (2007-17) and tested for ANAs, ENAs, anti-dsDNAs, ASMAs and AMAs. Non-organ-specific immunoreactivity was found to be significantly higher in patients with 47,XXY KS (14%) than in the controls (2%, p = 0.002). Among all the antibodies investigated, only ANAs were observed significantly more frequently in patients with 47,XXY KS (12.1%) than in the controls (2%, p = 0.004). No anti-dsDNA immunoreactivity was found. Stratifying by testosterone replacement therapy (TRT), non-organ-specific autoantibody frequencies were higher in TRT-naive (p = 0.01) and TRT-treated groups than in controls. No patients with HGA were found positive for the various autoantibodies. Non-organ-specific autoantibodies were significantly present in 47,XXY adult patients. Conversely, HGAs did not appear to be target of non-organ-specific immunoreactivity, suggesting that KS and HGAs should be considered as two distinct conditions. The classification and diagnosis of systemic autoimmune diseases is frequently difficult. To support a correct clinical evaluation of KS disease and to prevent eventual secondary irreversible immune-mediated damages, we highlight the importance of screening for non-organ-specific autoimmunity in Klinefelter's syndrome.

Clinical, Diagnostic, and Therapeutic Aspects of Growth Hormone Deficiency During the Transition Period: Review of the Literature.

The role of growth hormone (GH) during childhood and adulthood is well established. Once final stature is reached, GH continues to act during the transition, the period between adolescence and adulthood in which most somatic and psychological development is obtained. The achievement of peak bone mass represents the most relevant aspect of GH action during the transition period; however, equally clear is its influence on body composition and metabolic profile and, probably, in the achievement of a complete gonadal and sexual maturation. Despite this, there are still some aspects that often make clinical practice difficult and uncertain, in particular in evaluating a possible persistence of GH deficiency once final stature has been reached. It is also essential to identify which subjects should undergo re-testing and, possibly, replacement therapy, and the definition of unambiguous criteria for therapeutic success. Moreover, even during the transition phase, the relationship between GH substitution therapy and cancer survival is of considerable interest. In view of the above, the aim of this paper is to clarify these relevant issues through a detailed analysis of the literature, with particular attention to the clinical, diagnostic and therapeutic aspects.

Hypothalamo-Pituitary axis and puberty.

Puberty is a complex process that culminates in the acquisition of psychophysical maturity and reproductive capacity. This elaborate and fascinating process marks the end of childhood. Behind it lies a complex, genetically mediated neuroendocrine mechanism through which the gonads are activated thanks to the fine balance between central inhibitory and stimulating neuromodulators and hormones with both central and peripheral action. The onset of puberty involves the reactivation of the hypothalamic-pituitary-gonadal (HPG) axis, supported by the initial "kiss" between kisspeptin and the hypothalamic neurons that secrete GnRH (the GnRH "pulse generator"). This pulsatile production of GnRH is followed by a rise in LH and, consequently, in gonadal steroids. The onset of puberty varies naturally between individuals, and especially between males and females, in the latter of whom it is typically earlier. However, pathological variations, namely precocious and delayed puberty, are also possible. This article reviews the scientific literature on the physiological mechanisms of puberty and the main pathophysiological aspects of its onset.

Seminal plasma miRNAs in Klinefelter syndrome and in obstructive and non-obstructive azoospermia.

MicroRNAs are small, non-coding, single-strand oligonucleotides which regulate gene expression. There is little evidence in the literature about their role in azoospermia and no studies have investigated their presence in the seminal plasma of men with Klinefelter syndrome. This retrospective study investigated if there were any differences in microRNA expression (miR-509-5p, miR-122-5p, miR-34b-3p, miR-34c-5p) in the seminal plasma of patients with obstructive azoospermia, non-obstructive azoospermia and Klinefelter syndrome. Hormone levels were also investigated to identify any correlations with microRNA expression. We analysed 200 subjects (40 Klinefelter syndrome, 60 non-obstructive azoospermia with a normal karyotype, 60 obstructive azoospermia and 40 who were normozoospermic). All subjects underwent semen examination. Total RNA was obtained from seminal plasma and microRNA expression was analysed by RT-qPCR. There was a significant reduction in the expression of all investigated miRNAs in the seminal plasma of all patient categories in comparison with controls. There was a weak negative correlation between FSH values and miR-509-5p expression in non-obstructive azoospermic patients (r = - 0.391; p = 0.014). We hypothesize that in non-obstructive azoospermia and Klinefelter syndrome patients, the downregulation of microRNAs may be caused by damage to the germ cells and aberrant spermatogenesis. In our opinion the identification of seminal plasma microRNAs deriving almost exclusively from the testes could be essential for the development of specific biomarkers for male infertility. The expression of such microRNAs, in combination with hormone values, could comprise testicular markers of abnormal spermatogenesis and failed mature sperm production.

Metabolic and cardiovascular risk factors in Klinefelter syndrome.

Klinefelter syndrome (KS), which normally presents with a 47,XXY karyotype, is the most common sex chromosome disorder in males. It is also the most common genetic cause of male infertility. KS subjects are typically tall, with small and firm testes, gynecomastia, broad hips, and sparse body hair, although a less evident presentation is also possible. KS is also characterized by a high prevalence of hypogonadism, metabolic syndrome (MetS) and cardiovascular disease. The aim of this article is to systematically review metabolic and the cardiovascular risk factors in KS patients. Hypogonadism has an important role in the pathogenesis of the changes in body composition (particularly visceral obesity) and hence of insulin resistance and MetS, but the association between KS and MetS may go beyond hypogonadism alone. From childhood, KS patients may show an increase in visceral fat with a reduction in lean body mass and an increase in glucose and impaired fat metabolism. Their increased incidence of congenital anomalies, epicardial adipose tissue, and thromboembolic disease suggests they have a higher risk of cardiovascular disease. There is conflicting evidence on the effects of testosterone therapy on body composition and metabolism.

Androgenetic alopecia: effects of oral finasteride on hormone profile, reproduction and sexual function.

PURPOSE: Androgenetic Alopecia (AGA) is a common non-cicatricial alopecia. AGA treatment with finasteride was reported to have sexological side effects and its induced hormonal alterations could damage spermatogenesis. Thus, in patients affected by AGA undergoing oral therapy with Finasteride 1 mg/die, we aimed to evaluate the presence of modification in sperm parameters, hormone profile and sexual function. METHODS: We retrospectively evaluated 55 male subjects aged 18-45 years with AGA who underwent systemic therapy with Finasteride 1 mg/die. Each subject underwent semen and blood hormone analysis, IIEF15 questionnaire administration at baseline (T0) at 6 (T6) and 12 (T12) months after the beginning of therapy and 1 year after treatment discontinuation (TD). RESULTS: At T6 we detected a statistically significant worsening of total sperm number (232.4 ± 160.3 vs. 133.2 ± 82.0; p = 0.01 vs. T0) and abnormal forms (79.8 ± 6.0 vs. 82.7 ± 5.7; p < 0.05 vs. T0). No difference was found for all sperm parameters at T12 and T24, except for the percentage of abnormal forms (79.8 ± 6.0 vs. 82.6 ± 4.8; p < 0.05 T24 vs. T0). Testosterone levels were increased at T0 vs. T6 (22.1 ± 7.1 vs. 28.0 ± 8.0 ng/mL; p < 0.05). No significant differences of IIEF15 questionnaire were detected across the study. CONCLUSIONS: Finasteride is associated with significant seminological and testosterone alterations, but no sexual dysfunctions were reported during treatment of these andrologically healthy subjects. Although, sperm parameters seem to return comparable to baseline after treatment discontinuation, it is advisable to perform a careful andrological evaluation before treatment.

Long-Term Follow Up of the Erectile Function of Testicular Cancer Survivors.

The diagnosis of testicular cancer (TC) can have a considerable and persistent impact on a patient's sexuality, especially given its location. The high prevalence of TC in young adults, and the good prognosis, explain the great interest in sexual dysfunction and its influence on post-treatment quality of life. The aim of this study was to evaluate the impact of the diagnosis and treatments (inguinal orchiectomy and chemotherapy) on sex life. For this purpose, we recruited 241 TC patients attending the Laboratory of Seminology-Sperm Bank "Loredana Gandini" for sperm cryopreservation (mean age 31.3 ± 6.9 years) and 223 cancer-free healthy men who were undergoing andrological screening (mean age 32.0 ± 7.7 years). The IIEF-15 questionnaire was administered at the baseline (post-orchiectomy, pre-chemotherapy-T0) and at 6 (T1), 12 (T2), 18 (T3), 24 (T4), 48 months (T5) and >5 years (T6, median 96 months) after chemotherapy to all patients, to evaluate the following domains: erectile function (EF), orgasmic function (OF), sexual desire (SD), intercourse satisfaction (IS) and overall satisfaction (OS). A subgroup of patients also underwent blood sex hormone analysis for further correlations with IIEF scores. At the baseline, 37.7% of patients had erectile dysfunction (EF score <26) and all IIEF domains except OF showed significantly lower scores than in controls (p < 0.001). Long-term follow-up revealed persistently lower scores in TC survivors than in controls for EF, SD, IS, and OS. Furthermore, most IIEF domains did not improve significantly in TC patients during the duration of the follow-up, with the exception of EF, which showed a significant improvement from T2. Finally, no significant correlation was found between hormone levels (gonadotropin and testosterone) and IIEF-15 scores. In conclusion, TC and its treatment have a significant effect on sexuality. The absence of a clear correlation with biochemical hypogonadism suggests that this may to a large extent be due to the surgical procedure itself, or to the psychological impact of a cancer diagnosis.

Ovarian Reserve Reduction With Surgery Is Not Correlated With the Amount of Ovarian Tissue Inadvertently Excised at Laparoscopic Surgery for Endometriomas.

The aim of the present study was to evaluate the effect of laparoscopic cystectomy on ovarian reserve by means of anti-Müllerian hormone (AMH) serial measurements and to compare AMH values with the number of inadvertently removed follicles in histological specimens. Fifty-two women were enrolled: 34 patients with endometriomas (group 1) and 18 patients with other benign ovarian cysts (group 2). All patients underwent laparoscopic cystectomy performed by a single experienced surgeon. The AMH was measured before, and 1, 3, and 6 months after cystectomy in group 1, and before and 6 months after surgery in group 2. Preoperative AMH levels (mean [standard deviation, SD]) in group 1 (3.39 [2.43] ng/mL) were not significantly different from group 2 (3.74 [2.57] ng/mL; P = .68). In group 1, a significant decrease in AMH levels of 43.4% was observed at 1 month (1.93 [1.36]; P = .003), and of 63.1% at 3 months (1.25 [1.00]; P = .007) postoperatively. The AMH increased not significantly between the third and sixth months in group 1 (+9.4%). Six months after surgery, AMH was reduced by 59.3% compared to baseline values in group 1 (P = .012), and by 29.5% in group 2 (P = .200). A significant difference in the AMH decrease was present between bilateral and monolateral endometriomas (P = .006). There was no correlation between the reduction rate of AMH and the number of follicles inadvertently removed in patients with endometriomas (P = .669). In conclusion, AMH decreases significantly after surgical excision of ovarian endometriomas. The postoperative decrease does not appear to correlate with the amount of ovarian tissue inadvertently excised with the endometrioma wall.

Inhibin B: are modified ranges needed for orchiectomised testicular cancer patients?

Inhibin B is a gonadal hormone that downregulates the pituitary production of follicle-stimulating hormone (FSH). In recent years, inhibin B has proved to be an excellent marker of spermatogenesis and even a predictive factor for the recovery of fertility in patients undergoing orchiectomy and antineoplastic treatments. We propose to study inhibin B levels in orchiectomised testicular cancer patients, in order to identify a minimum value representative of normal semen quality. This retrospective study evaluates hormonal and semen parameters of 290 normozoospermic patients attending the Laboratory of Seminology - Sperm Bank "Loredana Gandini" (Rome, Italy) for cryopreservation of seminal fluid following a diagnosis of testicular cancer (TC group) and 117 healthy, normozoospermic men as a control group (CTR group). The percentile distribution of gonadotropin and inhibin B values in the TC and CTR groups was analyzed. There was a statistically significant difference between the two groups in the levels of all hormones (P ≤ 0.001) and in all semen parameters (P < 0.05). About 20% of TC patients revealed inhibin B levels below the 5th percentile of CTR group, despite normozoospermia, and 31.4% had normal spermatogenesis in the presence of FSH values >95th percentile of CTR group. Orchiectomised patients for testicular cancer presented inhibin B levels lower than healthy patients, despite normozoospermia. Our study revealed the poor sensitivity of the current inhibin B reference range when applied to monorchidic patients, suggesting the need to establish more representative ranges to enable more appropriate counseling in relation to the patient's new endocrine condition.

Evidence of increased humoral endocrine organ-specific autoimmunity in severe and classic X-chromosome aneuploidies in comparison with 46,XY control subjects.

OBJECTIVE: In literature, the importance of X-linked gene dosage as a contributing factor for autoimmune diseases is generally assumed. However, little information is available on the frequency of humoral endocrine organ-specific autoimmunity in X-chromosome aneuploidies. In our preliminary study, we investigated the endocrine organ-specific humoral autoimmunity relative to four different organ-specific autoimmune diseases in a group of adult 47,XXY KS patients and in adults 46,XY control males (type 1 diabetes, T1DM; Addison's disease, AD; Hashimoto thyroiditis, HT; autoimmune chronic atrophic gastritis, AG). The aim of the present study is to evaluate the frequency of autoantibodies (Abs) specific for T1DM, AD, HT, and AG in rarer higher grade X-chromosome aneuploidies (HGA) and in 47,XXY children. DESIGN AND METHODS: Samples from 192 Caucasian patients with an X-chromosome aneuploidy (176 patients (55 children, 121 adults) with 47,XXY karyotype (KS patients) and 16 HGA patients (eight children, eight adults)) recruited from Sapienza, University of Rome (2007-2017) were tested for Abs specific for T1DM (insulin-Abs, GAD-Abs, IA-2-Abs, Znt8-Abs), HT (TPO-Abs), AD (21-OH-Abs), and AG (APC-Abs). The results were compared to those found in 213 46,XY control subjects (96 children, 117 adults). RESULTS: Altogether humoral organ-specific immunoreactivity was found in 13% of KS and HGA patients, with a significantly higher frequency than in the controls (p=.008). Almost 19% of HGA patients were positive for at least one of the organ-specific Abs investigated compared to 12.5% of KS patients. The frequency of the overall immunoreactivity was higher in KS children than in KS adults. The frequency of diabetes-specific Abs was significantly higher in the patient cohort than in controls (p=.005). Thyroid- and gastric-specific autoimmunity was also found in KS and HGA patients, while adrenal-specific immunoreactivity was rare. CONCLUSIONS: These results suggest for the first time that the risk of endocrine organ-specific humoral autoimmunity progressively increases with the severity of X-chromosome polisomy. The screening for diabetes-, thyroid-, and gastric-specific autoimmunity should be considered in clinical practice for identifying rare and classic X-chromosome aneuploid patients at risk of developing organ-specific autoimmune diseases.

Preliminary findings on the association between attachment patterns and levels of growth hormone in a sample of children with non-organic failure to thrive

Introduction: Deficiency of growth hormone (GH) in absence of pituitary injuries is one of the causes of short stature and of the non organic failure to thrive (NOFTT) condition. Advances in developmental psychology have highlighted the role of emotions and caregiving behaviors in the organization of child's personality and psychobiology, with the mother-son attachment bond being considered a fundamental developmental experience. The objective of the present preliminary study was to assess whether there are significant correlations between attachment patterns and GH levels in a sample of subjects with NOFTT. Methods: Overall, 27 children (mean age 9.49±2.63 years) with NOFTT were enrolled. Perceived attachment security was assessed through the Security Scale (SS) and its subscales focused on maternal and paternal security. Pearson partial correlation was used to test associations between GH levels and SS measures adjusting for confounding factors (i.e. age, gender and body mass index). Results: Across all subjects, GH was significantly positively correlated with general security (r=0.425; p=0.038) and maternal security (r=0.451; p=0.027) and not significantly correlated with paternal security (r=0.237; p=0.264). Discussion: These findings preliminarily suggest that the association between GH levels and perceived attachment security may play a role in the pathophysiology of NOFTT and add to the accumulating evidence that attachment patterns may be related with specific psychoendocrine underpinnings.

Endocrine and metabolic evaluation of classic Klinefelter syndrome and high-grade aneuploidies of sexual chromosomes with male phenotype: are they different clinical conditions?

OBJECTIVE: Klinefelter syndrome (KS) is the most common sex chromosome aneuploidy in males. As well as classic KS, less frequent higher-grade aneuploidies (HGAs) are also possible. While KS and HGAs both involve testicular dysgenesis with hypergonadotropic hypogonadism, they differ in many clinical features. The aim of this study was to investigate the endocrinal and metabolic differences between KS and HGAs. DESIGN: Cross-sectional, case-control study. METHODS: 88 patients with KS, 24 with an HGA and 60 healthy controls. Given the known age-related differences all subjects were divided by age into subgroups 1, 2 and 3. Pituitary, thyroid, gonadal and adrenal functions were investigated in all subjects. Metabolic aspects were only evaluated in subjects in subgroups 2 and 3. RESULTS: FT4 and FT3 levels were significantly higher in HGA than in KS patients in subgroups 1 and 2; in subgroup 3, FT4 was significantly higher in controls than in patients. Thyroglobulin was significantly higher in HGA patients in subgroup 1 than in KS patients and controls. Hypergonadotropic hypogonadism was confirmed in both KS and HGA patients, but was more precocious in the latter, as demonstrated by the earlier increase in gonadotropins and the decrease in testosterone, DHEA-S and inhibin B. Prolactin was significantly higher in HGA patients, starting from subgroup 2. Total and LDL cholesterol were significantly higher in HGA patients than in KS patients and controls, while HDL cholesterol was higher in controls than in patients. CONCLUSIONS: KS and HGAs should be considered as two distinct conditions.

A combined form of hypothyroidism in pubertal patients with non-mosaic Klinefelter syndrome.

Klinefelter syndrome has been associated with thyroid abnormalities, the genesis of which is not yet fully clear. The aim of this study was to evaluate thyroid function in Klinefelter syndrome subjects during the pubertal period. Chemiluminescent microparticle immunoassay was used to analyze Thyroid-Stimulating Hormone, fT3 and fT4 concentration in serum samples from 40 Klinefelter syndrome pubertal boys with classic 47,XXY karyotype and 157 healthy age-matched controls. 13 Klinefelter syndrome patients also underwent Thyrotropin-Releasing Hormone testing to evaluate hypothalamic-pituitary function. fT3 levels were significantly lower in Klinefelter syndrome patients than in age-matched controls (p < 0.001). No significant differences were found for Thyroid-Stimulating Hormone (p = 0.138) or fT4 (p = 0.274), but the serum levels of Klinefelter syndrome patients tended to cluster around the lower part of the reference range for the assay. Three of the thirteen Klinefelter syndrome patients undergoing the Thyrotropin-Releasing Hormone test had an adequate response, one had a prolonged response at 60 min and nine responded inadequately. This study demonstrated for the first time that pubertal Klinefelter syndrome patients have significantly lower fT3 serum levels than do healthy age-matched boys, whereas Thyroid-Stimulating Hormone and fT4 are normal, albeit at the lower end of the reference range. Most patients showed an inadequate/prolonged response to pituitary stimulation with Thyrotropin-Releasing Hormone. These findings suggest a combined form of both central and peripheral hypothyroidism in Klinefelter syndrome boys during pubertal development.

Screening of endocrine organ-specific humoral autoimmunity in 47,XXY Klinefelter's syndrome reveals a significant increase in diabetes-specific immunoreactivity in comparison with healthy control men.

The aim of this study was to evaluate the frequency of humoral endocrine organ-specific autoimmunity in 47,XXY Klinefelter's syndrome (KS) by investigating the autoantibody profile specific to type 1 diabetes (T1DM), Addison's disease (AD), Hashimoto thyroiditis (HT), and autoimmune chronic atrophic gastritis (AG). Sixty-one adult Caucasian 47,XXY KS patients were tested for autoantibodies specific to T1DM (Insulin Abs, GAD Abs, IA-2 Abs, Znt8 Abs), HT (TPO Abs), AD (21-OH Abs), and AG (APC Abs). Thirty-five of these patients were not undergoing testosterone replacement therapy TRT (Group 1) and the remaining 26 patients started TRT before the beginning of the study (Group 2). KS autoantibody frequencies were compared to those found in 122 control men. Six of 61 KS patients (9.8 %) were positive for at least one endocrine autoantibody, compared to 6.5 % of controls. Interestingly, KS endocrine immunoreactivity was directed primarily against diabetes-specific autoantigens (8.2 %), with a significantly higher frequency than in controls (p = 0.016). Two KS patients (3.3 %) were TPO Ab positive, whereas no patients were positive for AD- and AG-related autoantigens. The autoantibody endocrine profile of untreated and treated KS patients was not significantly different. Our findings demonstrate for the first time that endocrine humoral immunoreactivity is not rare in KS patients and that it is more frequently directed against type 1 diabetes-related autoantigens, thus suggesting the importance of screening for organ-specific autoimmunity in clinical practice. Follow-up studies are needed to establish if autoantibody-positive KS patients will develop clinical T1DM.

BRF1 mutations alter RNA polymerase III-dependent transcription and cause neurodevelopmental anomalies.

RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of brf1 in zebrafish embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III-related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development.