Presentation and Care for Children with Peripheral Precocious Puberty

Peripheral precocious puberty (PPP) refers to the early onset of sexual maturation that is independent of central nervous system control. The extensive differential diagnosis includes congenital and acquired causes. Presenting features depend on which class of sex steroids is involved, and diagnosis rests on hormonal and, if indicated, imaging and/or genetic studies. Effective treatment exists for nearly all causes of PPP. Ongoing research will advance our therapeutic armamentarium and understanding of the pathophysiologic basis of these conditions.

Hypogonadotropic Hypogonadism

Delayed puberty is defined as absent testicular enlargement in boys or breast development in girls at an age that is 2 to 2.5 SDS later than the mean age at which these events occur in the population (traditionally, 14 years in boys and 13 years in girls). One cause of delayed/absent puberty is hypogonadotropic hypogonadism (HH), which refers to inadequate hypothalamic/pituitary function leading to deficient production of sex steroids in males and females. Individuals with HH typically have normal gonads, and thus HH differs from hypergonadotropic hypogonadism, which is associated with primary gonadal insufficiency.

History of Puberty: Normal and Precocious

Spanning from bench to bedside, the history of normal and precocious puberty is characterized by a series of remarkable advances that have illuminated reproductive physiology and profoundly impacted clinical care. Early recognition of the hypothalamic and pituitary control of ovarian and testicular function led to the identification of GnRH as the key driver of pubertal onset. Decades later, discovery of the kisspeptin system further refined our understanding of human reproductive neuroendocrinology. Development of long-acting analogs of GnRH revolutionized the treatment of precocious puberty worldwide and ushered in the current era of an ever-expanding therapeutic armamentarium. Identification of monogenic etiologies of precocious puberty has further illustrated the exquisite complexity that comprises neurosecretory modulation of the hypothalamic GnRH neuron and may well lead to exciting novel targeted therapies.

Current State of Pediatric Reference Intervals and the Importance of Correctly Describing the Biochemistry of Child Development: A Review

Importance

Appropriately established pediatric reference intervals are critical to the clinical decision-making process and should reflect the physiologic changes that occur during healthy child development. Reference intervals used in pediatric care today remain highly inconsistent across a broad range of common clinical biomarkers.

Observations

This narrative review assesses biomarker-specific pediatric reference intervals and their clinical utility with respect to the underlying biological changes occurring during development. Pediatric reference intervals from PubMed-indexed articles published from January 2015 to April 2021, commercial laboratory websites, study cohorts, and pediatric reference interval books were all examined. Although large numbers of pediatric reference intervals are published for some biomarkers, very few are used by clinical and commercial laboratories. The patterns, extent, and timing of biomarker changes are highly variable, particularly during developmental stages with rapid physiologic changes. However, many pediatric reference intervals do not capture these changes and thus do not accurately reflect the underlying biochemistry of development, resulting in significant inconsistencies between reference intervals.

Conclusions and Relevance

There is a need to correctly describe the biochemistry of child development as well as to identify strategies to develop accurate and consistent pediatric reference intervals for improved pediatric care.

Cardiovascular Health of Youth During Gender-Affirming Testosterone Treatment: A Review

PURPOSE

Many birth-assigned female/transgender male and nonbinary people (identified as masculine spectrum here) begin gender-affirming testosterone therapy by the age of 24 years. Few data inform assessment of cardiovascular health of masculine spectrum youth as a specific subgroup of the 1.5 million transgender people in the United States. The purpose of this review is to help youth-serving practitioners consider, understand, and evaluate cardiovascular health in adolescent and young adult masculine spectrum patients receiving gender-affirming testosterone treatment.

METHODS

This is a narrative review intended to synthesize a broad body of clinical and research literature.

RESULTS

Common cardiovascular health changes associated with testosterone include increased red blood cell mass and likely insignificant changes in high-density lipoprotein and low-density lipoprotein levels. Changes in heart mass, heart electrophysiology, and endothelial reactivity are likely, based on extrapolation of data from adults. Testosterone may have indirect effects on cardiovascular health through influences on depression, anxiety, stress, and anorexia nervosa as well as on behaviors such as tobacco use.

CONCLUSIONS

Testosterone contributes importantly to the cardiovascular health and well-being of masculine spectrum gender-diverse youth. We need to do a better job of supporting these young people with data on cardiovascular health over the life span.

Short stature and the effect of human growth hormone: Guidelines for the care of people with spina bifida

It is estimated that a significant percentage of individuals with spina bifida (SB) are shorter than their age-matched typical peers. Parents of children with spina bifida may ask if human growth hormone is appropriate for their child. This article discusses short stature and the use of human growth hormone among children with SB. This guideline was developed for SB Healthcare Guidelines from the 2018 Spina Bifida Association's Fourth Edition of the Guidelines for the Care of People with Spina Bifida.

Individualized care for patients with intersex (disorders/differences of sex development): part I

The care of individuals with disorders/differences of sex development aims to enable affected individuals and their families to have the best quality of life, particularly those born with severe genital ambiguity. Two of the biggest concerns for parents and health professionals are: (1) making a gender assignment and (2) the decisions of whether or not surgery is indicated, and if so, when is best for the patient and parents. These decisions, which can be overwhelming to families, are almost always made in the face of uncertainties. Such decisions must involve the parents, include multidisciplinary contributions, have an underlying principle of full disclosure, and respect familial, philosophical, and cultural values. Assignment as male or female is made with the realization that gender identity cannot be predicted with certainty. Because of the variability among those with the same diagnosis and complexity of phenotype-genotype correlation, the use of algorithms is inappropriate. The goal of this article is to emphasize the need for individualized care to make the best possible decisions for each patient's unique situation.

Use of Gonadotropin-Releasing Hormone Analogs in Children: Update by an International Consortium

This update, written by authors designated by multiple pediatric endocrinology societies (see List of Participating Societies) from around the globe, concisely addresses topics related to changes in GnRHa usage in children and adolescents over the last decade. Topics related to the use of GnRHa in precocious puberty include diagnostic criteria, globally available formulations, considerations of benefit of treatment, monitoring of therapy, adverse events, and long-term outcome data. Additional sections review use in transgender individuals and other pediatric endocrine related conditions. Although there have been many significant changes in GnRHa usage, there is a definite paucity of evidence-based publications to support them. Therefore, this paper is explicitly not intended to evaluate what is recommended in terms of the best use of GnRHa, based on evidence and expert opinion, but rather to describe how these drugs are used, irrespective of any qualitative evaluation. Thus, this paper should be considered a narrative review on GnRHa utilization in precocious puberty and other clinical situations. These changes are reviewed not only to point out deficiencies in the literature but also to stimulate future studies and publications in this area.

Central precocious puberty in spina bifida children: Guidelines for the care of people with spina bifida

Children with spina bifida are at greater risk of developing central precocious puberty (CPP) compared to others. Therefore, early recognition and timely referral for further evaluation by a pediatric endocrinologist allows appropriate management that reduces the impact of CPP. This article discusses the diagnosis and management of CPP in children with spina bifida. This guideline was developed for SB Transition Healthcare Guidelines from the 2018 Spina Bifida Association's Fourth Edition of the Guidelines for the Care of People with Spina Bifida.

Bicalutamide as an Androgen Blocker With Secondary Effect of Promoting Feminization in Male-to-Female Transgender Adolescents

PURPOSE

The purpose of the study was to describe the novel use of bicalutamide in transgender youth.

METHODS

This is a retrospective review of patients with gender dysphoria followed in the pediatric endocrine clinic at Riley Hospital for Children.

RESULTS

Of 104 patients with gender dysphoria, 23 male-to-female adolescents received bicalutamide 50 mg daily as a second-line puberty blocker after insurance company denial of a gonadotropin-releasing hormone analog. Six patients received estrogen concurrently. Of 13 patients treated exclusively with bicalutamide seen in follow-up, 84.6% had breast development within 6 months, the majority being ≥ Tanner stage III.

CONCLUSIONS

Bicalutamide may be an alternative to gonadotropin-releasing hormone analogs in transgender male-to-female youth who are also ready to undergo physical transition.

GH safety workshop position paper: a critical appraisal of recombinant human GH therapy in children and adults

Recombinant human GH (rhGH) has been in use for 30 years, and over that time its safety and efficacy in children and adults has been subject to considerable scrutiny. In 2001, a statement from the GH Research Society (GRS) concluded that 'for approved indications, GH is safe'; however, the statement highlighted a number of areas for on-going surveillance of long-term safety, including cancer risk, impact on glucose homeostasis, and use of high dose pharmacological rhGH treatment. Over the intervening years, there have been a number of publications addressing the safety of rhGH with regard to mortality, cancer and cardiovascular risk, and the need for long-term surveillance of the increasing number of adults who were treated with rhGH in childhood. Against this backdrop of interest in safety, the European Society of Paediatric Endocrinology (ESPE), the GRS, and the Pediatric Endocrine Society (PES) convened a meeting to reappraise the safety of rhGH. The ouput of the meeting is a concise position statement.

Reproductive Issues in Women with Turner Syndrome

Turner syndrome is one of the most common chromosomal abnormalities affecting female infants. The severity of clinical manifestations varies and it affects multiple organ systems. Women with Turner syndrome have a 3-fold increase in mortality, which becomes even more pronounced in pregnancy. Reproductive options include adoption or surrogacy, assisted reproductive techniques, and in rare cases spontaneous pregnancy. Risks for women with Turner syndrome during pregnancy include aortic disorders, hepatic disease, thyroid disease, type 2 diabetes, and cesarean section delivery. Providers must be familiar with the risks and recommendations in caring for women with Turner syndrome of reproductive age.

Treatment of hypogonadism in males

The treatment of adolescent males with hypogonadism using testosterone is dependent on the underlying diagnosis as well as the patient's and family's preferences. Those with testicular failure, always a pathologic condition, begin lifelong therapy, while short-term therapy is often begun for those who have a delayed puberty. There is a wide variety of testosterone formulations available, with differences in adverse events sometimes associated with the method of administration. The goals of treatment involve stimulating physical puberty, including achievement of virilization, a normal muscle mass and bone mineral density for age, and improvement in psychosocial wellbeing. While androgen therapy results in physical changes of puberty, the potential for fertility must be considered for those with permanent gonadotropin deficiency. in this population, therapy with gonadotropins or gonadotropin releasing hormone may be effective. For those with testicular failure, fertility may be possible but requires assisted reproductive procedures.

Neuroendocrine alterations in the exercising human: implications for energy homeostasis

Complex mechanisms exist in the human to defend against adverse effects of negative energy balance. These include alterations of hormone secretion affecting the growth hormone/insulin-like growth factor system, the adrenal axis, and the reproductive system, particularly in females. Energy deficits are least partially offset by neuroendocrine mechanisms regulating appetite and satiety. The complex feedback mechanisms reporting peripheral fat and energy stores to the central nervous system involve secretion of the peptide hormones leptin and ghrelin, which act centrally on neurons in the arcuate nucleus and anteroventral periventricular area. In addition to appetite regulation, these hormones exert influences on spatially and functionally-related mechanisms regulating reproductive function, such as the kisspeptin-gonadotropin releasing hormone system. Negative energy balance often occurs partially as a result of strenuous and repetitive physical exercise. Exercise stress leads to increased cortisol secretion, but this action is mediated through the induced negative energy balance. In healthy adults with energy deficits, this exercise-induced stress appears to be more important than pure psychological stress in impairing reproductive function. Estrogen deficiency resulting from negative energy balance has important adverse effects on bone density as well as bone microarchitecture, and it may also adversely affect markers of cardiovascular disease.

Treatment and outcomes of precocious puberty: an update

Precocious puberty is a common problem affecting up to 29 per 100,000 girls per year. The earliest identified neuroendocrine change in early puberty thus far is increased kisspeptin secretion from the arcuate nucleus and the anteroventral paraventricular nucleus of the hypothalamus. The regulation of kisspeptin secretion is not well understood, but neurokinin B and dynorphin provide autocrine regulation. The etiologies of precocious puberty may be subdivided into GnRH-dependent and GnRH-independent causes. GnRH-dependent precocious puberty, often called central precocious puberty (CPP), is usually treated with GnRH analogs. Newer developments in the treatment of CPP include expanded data on the safety and efficacy of the subdermal histrelin implant, which is useful for long-term treatment, although removal may be difficult in some cases. Preliminary data suggest that the implant may be left in place for up to 2 years without loss of biochemical suppression. In the last 2 years, more data have been published concerning extended-release leuprolide acetate injections that indicate that the 11.25-mg dose may not provide full biochemical suppression but may clinically suppress signs of puberty, including the accelerated growth velocity and advanced skeletal maturation seen in CPP. Treatment options for familial male-limited precocious puberty and McCune-Albright syndrome are expanding as well, although data are preliminary. Long-term outcome studies of CPP indicate overall good menstrual and reproductive function, but the prevalence of polycystic ovary syndrome may be higher than in the general population. Remarkably few studies have evaluated the behavioral and psychological outcomes of precocious puberty, in contrast to early normal maturation. Additional outcome studies of endocrine, metabolic, and psychological effects of CPP are clearly needed.

Identification of a novel heterozygous IGF1 splicing mutation in a large kindred with familial short stature

BACKGROUND/AIMS

Insulin-like growth factor (IGF)-I is critical for normal human growth. Extremely rare homozygous mutations of the IGF1 gene severely impair intrauterine growth, intellectual development and postnatal growth. CASE/METHOD: A young male presented with postnatal growth retardation (-4.0 height SDS). His serum IGF-I concentration was low (115 µg/l, -2.21 SDS) and increased minimally to 130 µg/l (-1.82 SDS) on GH therapy, and he was analyzed for defect(s) in the GH-IGF-I axis. Severe short stature could be traced back several generations.

RESULTS

From the proband and 4 other severely short-statured family members, two novel, heterozygous, variants were identified in the IGF1 gene: c.207G>A in exon 3 and c.402+1G>C in the donor splice site of intron 4. The IGF1 gene was normal in 11 normal stature family members, and, interestingly, in 5 other short-statured family members. Study of IGF1 mRNA indicated c.402+1G>A induced splicing out of exon 4, leading to a predicted frameshift and protein truncation.

CONCLUSIONS

A novel heterozygous IGF1 splicing variant is associated with familial short stature in an extended family. Although it remains unclear whether this heterozygous mutation is the cause of the growth failure, the extreme rarity of IGF1 gene defects makes these cases of considerable interest.

Discrepancies between reported self-monitored blood glucose results and point-of-care hemoglobin A1c in children with diabetes: lessons to be learned

BACKGROUND

The hemoglobin A1c (HbA1c) assay is considered the gold standard for assessing glycemic control in children and adolescents with type 1 diabetes mellitus (T1DM). In recent years, point-of-care (POC) testing has been more commonly used in the outpatient clinic. However, despite its popularity, little is known about the accuracy of the POC methods in children.

PATIENTS AND METHODS

In this case series, we describe seven children-six with T1DM and one with type 2 diabetes mellitus-who had major discrepancies between measured POC HbA1c via A1cNow+(®) (Bayer Healthcare Metrika, Sunnyvale, CA) and self-monitored blood glucose records.

RESULTS

In six subjects, the discrepancy was explained by the presence of the hemoglobin S trait, and an additional subject had the hemoglobin C trait.

CONCLUSIONS

This report demonstrates that as with all laboratory tests, the HbA1c test is subject to limitations, particularly in children with hemoglobin variants. Increased awareness regarding these limitations among healthcare professionals is paramount, especially with the increased use of the HbA1c POC method in the medical community. Failure to recognize these limitations can lead to unnecessary medical, financial, and social interventions that could have profound impact on the patient-doctor relationship.

Ease of use and preference for a new disposable self-injection pen compared with a reusable pen for administering recombinant human growth hormone: A multicenter, 2-month, single-arm, open-label clinical trial in patient-caregiver dyads

BACKGROUND

Improved ease of use of drug-delivery devices may enhance compliance. Development of an easier-to-use device for administration of recombinant human growth hormone (rhGH) may thus be beneficial for patients and their caregivers.

OBJECTIVE

This study compared ease of use and preference for a new disposable rhGH injection pen relative to previous experience with the currently available reusable pen in standard practice. Both pens deliver the same formulation of rhGH.

METHODS

This multicenter, single-arm, open-label study assessed ease of use and preference for the 2 injection pens in patient-caregiver dyads. Eligible children were aged 8 through 18 years, were currently being treated with rhGH, and had been compliant with use of the current reusable pen for ≥ 3 months before study entry. A validated self-reported Injection Pen Assessment Questionnaire was administered twice during the study-at baseline (to assess perceptions of the reusable pen) and after 2 months of use of the new disposable pen-to assess ease of use of the individual pens (rated on a 5-point Likert-type scale), the comparative ease of use of the 2 pens, and pen preference. The primary end point was the proportion of dyads who rated the new pen as no different or easier to use than the current pen. Regardless of treatment or suspected causal relationship to the investigational product, all observed or volunteered adverse events (AEs) were recorded and rated as mild, moderate, or severe.

RESULTS

Of 137 screened dyads, 136 (91 boys, 45 girls) were included in the safety population and 133 were included in the efficacy population. The children had a mean age of 12.3 years, a mean weight of 42.2 kg, a mean height of 145.9 cm, and a mean body mass index of 19.3 kg/m(2); 84.6% of the children were white. The majority (82.4%) of adult dyad members were subjects' mothers. The adult dyad members were more likely than the child members to be responsible for preparing the injection (82.0%) and administering the injection (72.9%). Overall, 73.7% of dyads rated the new disposable pen no different or easier to use than the reusable pen (95% CI, 66.2%-81.2%), and 65.2% rated the disposable pen no different or preferable to the reusable pen (95% CI, 57.0%-73.3%). Overall, 60 all-causality AEs occurred in 28 subjects (20.6%), most of them (93.3%) either mild or moderate in intensity. Eight device-related AEs occurred in 7 subjects (5.1%) (injection-site hematoma in 3 and injection-site pain in 5). The most common AEs were headache (7 events), injection-site pain (5), upper respiratory tract infection (4), and pyrexia (4). No deaths or serious AEs were reported.

CONCLUSIONS

Nearly three quarters of patients and caregivers reported that the new disposable pen was no different or easier to use than the reusable pen, and nearly two thirds preferred the disposable pen. No safety concerns were identified. The findings suggest that the improvements in the new pen were recognized by patients and caregivers.

Bicalutamide and third-generation aromatase inhibitors in testotoxicosis

Testotoxicosis, a form of gonadotropin-independent precocious puberty, results from an activating mutation of the luteinizing hormone receptor expressed in testicular Leydig cells. Affected males experience early testosterone secretion, virilization, advancing bone age, and resultant short stature. Recently, the use of combination therapy with a potent antiandrogen agent (bicalutamide) and a third-generation aromatase inhibitor (anastrozole or letrozole) was reported to yield encouraging short-term results. We present here the results of longer-term treatment (4.5 and 5 years) with this combination therapy in 2 boys who demonstrated that it is well tolerated, slows bone-age advancement in the face of continued linear growth, and prevents progression of virilization.

Update from the GHMonitorSM observational registry in children treated with recombinant human growth hormone (Saizen)

Since 2003, the GH MonitorSM, an observational registry, has collected data on pediatric subjects treated with Saizen (recombinant human growth hormone (r-hGH)) in the United States and Canada. This article provides an update on the demographic characteristics of subjects enrolled in the GHMonitorSM Registry. As of August 2007, 1733 subjects were enrolled (68.9% male). The most common primary diagnosis at screening was idiopathic growth hormone deficiency (56.5% of subjects).Of those subjects with available data, mean height standard deviation (SD) score was -2.1+/-1.0, mean weight SD score was -1.4+/-1.5, and mean body mass index SD score was -0.1+/-1.3. Among subjects in whom the presence or absence of other pituitary hormone deficiencies was recorded, 16.1% had multiple pituitary hormone deficiencies. Most patients reported high compliance with therapy (92.6% missed 0-3 doses per month); compliance was similar for all delivery devices (needle/syringe, cool.clickTM or one.clickTM) used. Two serious adverse events related to Saizen (hospitalization for placement of right frontal ventriculostomy and right frontal craniotomy for transcallosal resection of a large recurrent craniopharyngioma and left slipped capitofemoral epiphysis that required pinning of the right hip) were reported in the period from August 2006 to August 2007. This update of the GHMonitorSM Registry continues to provide insight into the characteristics of children treated with this agent and continued evidence of the efficacy and safety of Saizen in children.

The impact of assay sensitivity in the assessment of diseases and disorders in children

Accurate measurement of the low levels of testosterone (T) and estradiol (E(2)) present in normal children and in children with disorders of puberty and sexual development is critical both for appropriate diagnosis and treatment and for clinical research studies. However, measurement of these levels lacks needed precision because of inadequate sensitivity of most commercially available assays and poor accuracy at the low levels found in normal childhood and most disorders. While immunoassays presently do not appear to have the potential to provide more accurate measurements, isotope dilution-gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry techniques offer promise to meet this need to improve clinical care and research.

Issues and trends in pediatric growth hormone therapy--an update from the GHMonitor observational registry

The GHMonitor observational registry collates data on pediatric subjects receiving Saizen (recombinant human growth hormone (GH)) therapy. From January 2003 through August 2006, 1335 subjects were enrolled in the registry, approximately two-thirds of whom are male. The most common diagnosis in the registry is idiopathic growth hormone deficiency (58%). Most subjects in GHMonitor are receiving Saizen doses using a needle-free delivery device, the cool.click (73%). Mean height standard deviation scores show an improvement from -2.1 at screening to -1.1 following 3 years of Saizen therapy. To date, adverse events have been reported in 4% of subjects. Three serious adverse events were identified to be related to Saizen by the primary investigator: cellulitis at the injection site, behavioral problems/suicidal ideation, and enlargement of a craniopharyngioma. This article provides an update on data from the registry and briefly discusses topical and controversial issues in the treatment of pediatric patients requiring GH therapy.

Laboratory assays in pediatric endocrinology: common aspects

With a rapidly expanding armamentarium of tests, endocrinologists need the ability to critically assess a laboratory assay and to understand its application. There are numerous important issues to consider. Analytical validation ensures that an assay meets standards for sensitivity, specificity and reproducibility. Clinical validation allows the results of a test to be effectively applied to a given clinical situation. Antibody-based endocrine assays are typically either competitive or non-competitive. For competitive assays, an interference that decreases signal will lead to an apparent increase in the analyte concentration, while an interference that decreases signal in a non-competitive assay will cause an apparent decrease in the analyte concentration. Mass spectrometry is rapidly increasing in use and has its own promises and pitfalls. Numerous methods exist for determining reference intervals, each giving different results. Making endocrine diagnoses based on such intervals may be overly simplistic and collaboration between clinicians and the laboratory to establish clinical thresholds would be far more informative.

Growth after organ transplantation

Growth is an important feature of childhood, but it is usually impaired before and after organ transplantation. Modest catch-up growth often occurs after renal transplantation. Nevertheless, patients remain short due to the effects of steroids used for immunosuppression. Children with chronic liver failure are also growth impaired, although not to the same extent. They also frequently have poor catch up growth after transplantation, again due to steroids. There are several randomized controlled clinical trials reporting growth hormone (GH) use after renal transplantation. These consistently show a beneficial effect of GH on linear growth. Patients with histories of frequent acute rejections before GH may have increased risk of acute rejection during treatment. Few data exist on liver transplant patients, although GH also appears effective. GH use may be safe and effective for renal transplant recipients who have been stable without acute rejection episodes. There needs to be long-term study of GH use in liver and renal transplant patients. It is critical to focus efforts on improving growth in renal failure before transplantation through GH use and to improve posttransplant growth in all recipients by minimizing steroid exposure.

Genetics, clinical management and natural history of congenital hypothyroidism

Congenital hypothyroidism has an incidence of 1:3000-4000 newborns. In the past, it was a common cause of mental retardation, although newborn screening has improved the prognosis. Several transcription factors are crucial to the early organogenesis of the thyroid, including TITF1, FOXE1, PAX8 and HHEX. Nevertheless, a small minority of humans with congenital hypothyroidism carry mutations in these genes. Long-term follow-up studies show that with appropriate therapy, the mental and physical development of congenital hypothyroidism patients is in the normal range, although somewhat delayed when compared with appropriate controls. Critical issues of treatment include early diagnosis and rapid correction of hypothyroidism by ensuring rapid initiation of treatment and rapid normalization of thyroid-stimulating hormone levels, especially in cases of severe congenital hypothyroidism. There has been recent question of the need to treat premature infants with hypothyroxinemia but no elevation of the thyroid-stimulating hormone concentration. Numerous controlled studies of the short- and long-term effects of thyroid hormone supplementation have not shown a consistent benefit in this group of patients. Future research will investigate further the genetic underpinnings of the condition. There is a worldwide need to prevent congenital hypothyroidism by ensuring adequate dietary iodine and to develop infrastructure to diagnose and treat congenital hypothyroidism in developing countries.

Determination of trace isoflavone phytoestrogens in biological materials by capillary electrochromatography

Capillary electrochromatography using a specialty monolithic matrix was utilized in developing a rapid and highly efficient separation of isoflavones in biological materials. Without a preconcentration technique, it is relatively easy to reach ppm-ppb concentrations of these compounds in soy-based foods and verify them structurally using a photodiode array detector. With on-column preconcentration, we were able to measure low-ppb levels in human serum. Using blood samples from human volunteers, whose diet was supplemented by a soy-based product, the method has been validated for high-throughput screening of isoflavones in clinical studies.

Linkage analysis of a kindred with inherited 46,XY partial gonadal dysgenesis

We have reported a kindred in which 46,XY gonadal dysgenesis was inherited in an X-linked (or autosomal dominant sex-limited) manner and in which affected subjects did not have a large duplication of the short arm of the X-chromosome. In the present study we used linkage and sequence analyses to test the role of X-linked and various autosomal genes in the etiology of the familial 46,XY partial gonadal dysgenesis. For analysis of X-linkage, 28 microsatellite polymorphisms and 1 restriction fragment length polymorphism were studied. The genotypes of informative family members were determined at each locus, and data were analyzed. Despite the large number of loci tested, our studies did not establish linkage between the trait and an X-chromosomal locus. With respect to the study of autosomal genes, linkage analysis using a polymorphism within the 3'-untranslated region of the WT1 gene excluded involvement of WT-1 in the etiology of the abnormal gonadal differentiation of the family in this study. Similarly, linkage analysis using four microsatellites on the distal short arm of chromosome 9 was not consistent with linkage. Linkage analysis of a locus close to the SOX9 gene as well as analysis of the coding region of the SOX9 gene suggested that this gene was not associated with the trait in the affected subjects we studied. Our data suggest the role of an autosomal gene in the abnormal gonadal differentiation in the family in the study, but do not formally exclude the role of an X-chromosome gene.

Loss of sequences 3' to the testis-determining gene, SRY, including the Y pseudoautosomal boundary associated with partial testicular determination

The condition termed 46,XY complete gonadal dysgenesis is characterized by a completely female phenotype and streak gonads. In contrast, subjects with 46,XY partial gonadal dysgenesis and those with embryonic testicular regression sequence usually present ambiguous genitalia and a mix of Müllerian and Wolffian structures. In 46,XY partial gonadal dysgenesis gonadal histology shows evidence of incomplete testis determination. In 46,XY embryonic testicular regression sequence there is lack of gonadal tissue on both sides. Various lines of evidence suggest that embryonic testicular regression sequence is a variant form of 46,XY gonadal dysgenesis. The sex-determining region Y chromosome gene (SRY) encodes sequences for the testis-determining factor. To date germ-line mutations in SRY have been reported in approximately 20% of subjects with 46,XY complete gonadal dysgenesis. However, no germ-line mutations of SRY have been reported in subjects with the partial forms. We studied 20 subjects who presented either 46,XY partial gonadal dysgenesis or 46,XY embryonic testicular regression sequence. We examined the SRY gene and the minimum region of Y-specific DNA known to confer a male phenotype. The SRY-open reading frame (ORF) was normal in all subjects. However a de novo interstitial deletion 3' to the SRY-ORF was found in one subject. Although it is possible that the deletion was unrelated to the subject's phenotype, we propose that the deletion was responsible for the abnormal gonadal development by diminishing expression of SRY. We suggest that the deletion resulted either in the loss of sequences necessary for normal SRY expression or in a position effect that altered SRY expression. This case provides further evidence that deletions of the Y chromosome outside the SRY-ORF can result in either complete or incomplete sex reversal.

Abnormal gonadal differentiation in two subjects with ambiguous genitalia, Mullerian structures, and normally developed testes: evidence for a defect in gonadal ridge development

Among a group of patients with abnormal sexual differentiation, we have identified two subjects who had a 46,XY karyotype, ambiguous genitalia, and well-developed Müllerian structures, but normal appearing testes. The presence of ambiguous genitalia and persistent Müllerian structures implied both Leydig cell and Sertoli cell dysfunction, hence, gonadal dysgenesis. However, the normal testicular histology suggested that the underlying abnormality was not a defect in testis determination itself but an abnormality in timing of gonadal ridge and testis development. In one of the two subjects genomic DNA was available. The sequence of the SRY gene was normal. Because rare patients with partial androgen insensitivity may have a similar phenotype, the AR gene was evaluated by denaturing gradient gel electrophoresis (DGGE) and was normal. Some subjects with mutation of the WT1 gene or with deletion of the distal short arm of chromosome 9 may have similar phenotypes. The WT1 gene was studied by single-strand conformation polymorphism (SSCP) analysis and was normal. In addition, there was no loss of heterozygosity of polymorphic markers in distal 9p. The gene for Müllerian inhibiting substance (MIS) was also studied by SSCP and was normal. Although the exact mechanism for the defect in the two subjects is unknown, it may be due to an abnormality in a gene or genes involved in the timing of gonadal ridge development.

Assay of plasma testosterone during the first six months of life: importance of chromatographic purification of steroids

Determination of the plasma concentration of testosterone (T) is important in evaluating infants born with ambiguous genitalia and micropenis, and several commercially available kits provide a direct assay of T in unextracted plasma. Using plasma samples obtained from 36 subjects < 6 months old, we compared the concentration of plasma T measured by RIA after extraction and purification by column chromatography with the T concentration measured in a direct assay. When aliquots of samples were purified before RIA, the concentration of T was markedly lower than in the direct assay. In the first 3 weeks postpartum, results of the direct assay were 3.8-fold greater than those obtained after purification. This difference decreased over time, and by age 2 months there was fairly good agreement between the two methods. These data indicate that some direct assays of plasma T are inappropriate during the first 2 months postpartum.

Assay of plasma testosterone during the first six months of life: importance of chromatographic purification of steroids

Determination of the plasma concentration of testosterone (T) is important in evaluating infants born with ambiguous genitalia and micropenis, and several commercially available kits provide a direct assay of T in unextracted plasma. Using plasma samples obtained from 36 subjects &lt; 6 months old, we compared the concentration of plasma T measured by RIA after extraction and purification by column chromatography with the T concentration measured in a direct assay. When aliquots of samples were purified before RIA, the concentration of T was markedly lower than in the direct assay. In the first 3 weeks postpartum, results of the direct assay were 3.8-fold greater than those obtained after purification. This difference decreased over time, and by age 2 months there was fairly good agreement between the two methods. These data indicate that some direct assays of plasma T are inappropriate during the first 2 months postpartum.

Combined Leydig cell and Sertoli cell dysfunction in 46,XX males lacking the sex determining region Y gene

We have evaluated 3 individuals with a rare form of 46,XX sex reversal. All of them had ambiguous external genitalia and mixed wolffian and müllerian structures, indicating both Leydig cell and Sertoli cell dysfunction, similar to that of patients with true hermaphroditism. However, gonadal tissue was not ovotesticular but testicular with varying degrees of dysgenesis. SRY sequences were absent in genomic DNA from peripheral leukocytes in all 3 subjects. Y centromere sequences were also absent, indicating that testis development did not occur because of a low level mosaicism of Y bearing cells. The subjects in this report demonstrate that there is a continuum in the extent of testis determination in SRY-negative 46,XX sex reversal, ranging from nearly normal to minimal testicular development.