Speech and language development in children with 49,XXXXY syndrome.

49,XXXXY is the rarest X and Y chromosomal variation and is frequently characterized by expressive and receptive language dysfunction, low muscle tonus, and intellectual deficits. Due to the low incidence of this disorder, comprehensive studies analyzing the specific aspects of the speech and language phenotype in these boys have been uncommon. This is the first in-depth investigation of the speech and language profiles in a large cohort of boys with 49,XXXXY. Based on the clinical judgment of speech and language pathologists, there was an increased incidence (91.8%) of Childhood Apraxia of Speech (CAS), which has not been previously described in this disorder. In preschool boys, some significant differences were demonstrated between boys who received early hormonal treatment (n = 16) and untreated boys (n = 4) on the language scales (p = .047) on the Bayley Scales of Infants and Toddlers, as well as significant differences between treated (n = 13) and untreated boys (n = 8) on the Expressive One Word Picture Vocabulary Test (p = .008). No significant differences between treatment groups were found in school age children, however, treated groups demonstrated less discrepancies between expressive and receptive language. More research and larger samples are needed to determine the extent of the impact of testosterone treatment on boys with 49,XXXXY. This study identifies CAS as a potential explanation for the significant expressive language dysfunction and subsequent behavioral dysfunction. These findings may assist in facilitating more targeted treatment and improved outcomes for boys with 49,XXXXY.

49,XXXXY syndrome: A study of neurological function in this uncommon X and Y chromosomal disorder.

49,XXXXY is a rare chromosomal variation characterized by deficits in motor, language, and cognitive domains. This study reports on the neurological function and dysmorphic features in the largest cohort to date. Seventy-two boys with 49,XXXXY were evaluated on a variety of domains including a neurological examination and neuromotor assessments including the Beery Buktenica Developmental Test of Visual-Motor Integration, Sixth Edition, the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III), and the Bruininks-Oseretsky Test of Motor Proficiency, Second Edition. Results supported previous literature by describing high occurrences of truncal and extremity hypotonia, which significantly impacts on motor milestones and ambulation in this population. The boys presented with dysmorphic features including epicanthal folds, frontal bossing, and synophrys. Visual perception skills were mildly impaired and cranial nerves were typically intact, however capabilities in motor coordination and fine motor precision were greatly delayed, supporting deficits in refined and controlled hand movements versus widespread visual deficits. Preschool boys treated with testosterone replacement had significantly increased scores when compared to the untreated group on the BSID-III Psychomotor Development Index, further supporting previous research indicating that testosterone replacement may have a positive impact on neurodevelopmental outcomes in males with additional X chromosomes. Boys with 49,XXXXY may benefit from hormonal treatment in conjunction with early intervention services to address their significant motor deficits.

Early neurodevelopmental and medical profile in children with sex chromosome trisomies: Background for the prospective eXtraordinarY babies study to identify early risk factors and targets for intervention.

Sex chromosome trisomies (SCT), including Klinefelter syndrome/XXY, Trisomy X, and XYY syndrome, occur in 1 of every 500 births. The past decades of research have resulted in a broadening of known associated medical comorbidities as well as advances in psychological research. This review summarizes what is known about early neurodevelopmental, behavioral, and medical manifestations in young children with SCT. We focus on recent research and unanswered questions related to the risk for neurodevelopmental disorders that commonly present in the first years of life and discuss the medical and endocrine manifestations of SCT at this young age. The increasing rate of prenatal SCT diagnoses provides the opportunity to address gaps in the existing literature in a new birth cohort, leading to development of the eXtraordinarY Babies Study. This study aims to better describe and compare the natural history of SCT conditions, identify predictors of positive and negative outcomes in SCT, evaluate developmental and autism screening measures commonly used in primary care practices for the SCT population, and build a rich data set linked to a bank of biological samples for future study. Results from this study and ongoing international research efforts will inform evidence-based care and improve health and neurodevelopmental outcomes.

The behavioral profile of children aged 1-5 years with sex chromosome trisomy (47,XXX, 47,XXY, 47,XYY).

Children with SCT have an increased risk of suboptimal neurodevelopment. Previous studies have shown an elevated risk for neurobehavioral problems in individuals with SCT. However, not much is known about neurobehavioral problems in very young children; knowledge that could help with early identification of children at risk for suboptimal development, and that could help establish targets for early intervention. This study addressed the question of what the behavioral profile of children with SCT aged 1-5 years looks like. In total, 182 children aged 1-5 years participated in this study (NSCT =87, Nnonclinical controls = 95). Recruitment and assessment took place in the Netherlands and the United States. The SCT group was recruited through prospective follow-up (50%), information seeking parents (31%), and clinical referral (18%). Behavioral profiles were assessed with the child behavior checklist and the ages-and-stages social-emotional questionnaire. Levels of parent-rated problem behavior were higher in children with SCT. Difficulties with overall social-emotional functioning were already present in 1-year-olds, and elevated scores were persistent across the full age range. Affective and pervasive developmental behaviors were seen in late toddlerhood and prominent at preschool age. Anxiety, attention deficit, and oppositional defiant behaviors were seen in preschool-aged children. Within this cross-sectional study, the developmental trajectory of affective, pervasive developmental, and oppositional defiant behaviors seemed to be different for SCT children than nonclinical controls. Collectively, these results demonstrate the importance of behavioral screening for behavioral problems in routine clinical care for children with SCT from a young age. Social-emotional problems may require special attention, as these problems seem most prominent, showing increased risk across the full age range, and with these problems occurring regardless of the timing of diagnosis, and across all three SCT karyotypes.

Neurodevelopmental outcome of prenatally diagnosed boys with 47,XXY (Klinefelter syndrome) and the potential influence of early hormonal therapy.

This cross-sectional study examined the neurodevelopment of a large, prenatally diagnosed population of boys with 47,XXY; investigated the potentially positive effects of early hormonal therapy (EHT) on language, cognition, and motor in this population; and identified novel at risk biomarkers associated with 47,XXY. Two-hundred and seventy two evaluations were collected from 148 prenatally diagnosed boys with 47,XXY between 0 and 36 months and separated into one of three groups, depending on visit age: Y1 (0-12 months; n = 100), Y2 (13-24 months; n = 90), and Y3 (25-36 months; n = 82). Those who received EHT (administered by 12 months) were further separated (Y1, n = 37; Y2, n = 34; Y3, n = 30). Neurodevelopmental evaluations consisted of Preschool Language Scales, Early Language Milestone Scale, and Bayley Scales of Infant and Toddler Development and evaluated the effect of EHT on auditory comprehension, expressive communication, receptive language, cognition, and motor. EHT was found to be associated with a positive effect within the first year of life in these domains, as well as in the second and third year of life. Additionally, three novel at-risk biomarkers were identified in this cohort: feeding difficulties in infancy, positional torticollis, and the need for orthotics. The positive effects of EHT observed in language, cognition, and motor at variable stages within the first 3 years of life provide additional evidence into the possible efficacy of early biological treatment for boys with 47,XXY to address the neurodevelopmental dysfunction.

Sensory Features as a Marker of Autism Spectrum Disorders.

We explored sensory features as distinguishing characteristics of Autism spectrum disorder (ASD). Four groups of males (n = 36): Six with 47, XYY syndrome and ASD (XYY+ASD), six with 47, XYY syndrome and no ASD (XYY-ASD), 12 with idiopathic ASD (ASD-I) and 12 typically developing (TYP). The short sensory profile (SSP) the sensory challenge protocol (SCP) were used to assess sensory features. SSP Total Score for the YY+ASD was significantly lower than the XYY-ASD (p = .002) and TYP (p < .001), but were not different from ASD-I (p = .714). The XYY+ASD group had significantly lower baseline heart rate variability during the SCP than TYP (p = .044). Findings provide preliminary support of sensory features as important in ASD diagnosis.

Abnormal Auditory Mismatch Fields in Children and Adolescents with 47,XYY Syndrome.

47,XYY syndrome (XYY) is one of the common forms of sex chromosome aneuploidy in males. XYY males tend to have tall stature, early speech, motor delays, social and behavioral challenges, and a high rate of language impairment. Recent studies indicate that 20-40% of males with XYY meet diagnostic criteria for autism spectrum disorder (ASD; the rate in the general population is 1-2%). Although many studies have examined the neural correlates of language impairment in ASD, few similar studies have been conducted on individuals with XYY. Studies using magnetoencephalography (MEG) in idiopathic ASD (ASD-I) have demonstrated delayed neurophysiological responses to changes in the auditory stream, revealed in the mismatch negativity or its magnetic counterpart, the mismatch field (MMF). This study investigated whether similar findings are observed in XYY-associated ASD and whether delayed processing is also present in individuals with XYY without ASD. MEG measured MMFs arising from the left and the right superior temporal gyrus during an auditory oddball paradigm with vowel stimuli (/a/ and /u/) in children/adolescents with XYY both with and without a diagnosis of ASD, as well as in those with ASD-I and in typically developing controls (TD). Ninety male participants (6-17 years old) were included in the final analyses (TD, n = 38, 11.50 ± 2.88 years; ASD-I, n = 21, 13.83 ± 3.25 years; XYY without ASD, n = 15, 12.65 ± 3.91 years; XYY with ASD, n = 16, 12.62 ± 3.19 years). The groups did not differ significantly in age (p > 0.05). There was a main effect of group on MMF latency (p < 0.001). Delayed MMF latencies were found in participants with XYY both with and without an ASD diagnosis, as well as in the ASD-I group compared to the TD group (ps < 0.001). Furthermore, participants with XYY (with and without ASD) showed a longer MMF latency than the ASD-I group (ps < 0.001). There was, however, no significant difference in MMF latency between individuals with XYY with ASD and those with XYY without ASD. Delayed MMF latencies were associated with severity of language impairment. Our findings suggest that auditory MMF latency delays are pronounced in this specific Y chromosome aneuploidy disorder, both with and without an ASD diagnosis, and thus may implicate the genes of the Y chromosome in mediating atypical MMF activity.

Auditory evoked response delays in children with 47,XYY syndrome.

47,XYY syndrome (XYY) is a male sex chromosome disorder where individuals have an X chromosome and two copies of the Y chromosome. XYY is associated with a physical phenotype and carries increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD). Latencies of auditory evoked responses measured by magnetoencephalography have shown atypical prolongations in several neuropsychiatric and genetic disorders; specifically, delayed auditory responses have been observed in ASD. In this study, we investigated the associations of genotype and clinical phenotype with auditory processing. Whole cortex magnetoencephalography recorded during a passive auditory paradigm (500 Hz tones) was used to assess the auditory evoked response in three groups of male children: idiopathic ASD, typically developing, and XYY boys. Response waveforms were computed for left and right auditory cortex and latencies of the ∼50 ms (M50) and ∼100 ms (M100) components were determined. M50 latencies were significantly delayed compared with typically developing controls in children with ASD in the right hemisphere only, and in children with XYY in the left hemisphere only, irrespective of whether they met diagnostic criteria for ASD. Findings on the later M100 component trended in the same directions but did not attain significance, due to increased variance. Replicating previous findings, decreased M50 and M100 latencies with age were observed bilaterally. Overall, while XYY shares an electrophysiological phenotype (delayed evoked response latency) with idiopathic ASD, the hemispheric differences warrant further investigation.

A review of neurocognitive functioning and risk for psychopathology in sex chromosome trisomy (47,XXY, 47,XXX, 47, XYY).

PURPOSE OF REVIEW: About one in 650-1000 children is born with an extra X or Y chromosome, referred to as sex chromosome trisomies (SCTs). Studying SCTs may uncover unique insights in neurodevelopmental pathways underlying the risk for neurobehavioral problems and psychopathology. There is also a clinical need for more knowledge about the phenotype of SCT with the recent introduction of noninvasive prenatal screening. RECENT FINDINGS: The reviewed studies illustrate an increased vulnerability for psychopathology such as (symptoms of) autism spectrum disorder, attention-deficit/hyperactivity disorder, anxiety, depression and, to a lesser degree, psychotic disorders. Although traditionally the primary focus has been on language and learning problems, recent research suggests that impairments in executive functioning, social cognition and emotion regulation may also be key factors underlying the risk for neurobehavioral problems. SUMMARY: The research field of SCT is in need of a more longitudinal perspective to identify early markers of 'at risk' development, and to assess the effectiveness of early interventions. Neurocognitive markers that signal compromised neurodevelopment may prove to be helpful in this. Variability in the SCT phenotype provides a unique opportunity to identify not only genetic but also environmental factors that shape neurodevelopmental outcome, calling for studies focused on understanding individual differences.

Xq26.1-26.3 duplication including MOSPD1 and GPC3 identified in boy with short stature and double outlet right ventricle.

Xq25q26 duplication syndrome has been reported in individuals with clinical features such as short stature, intellectual disability, syndromic facial appearance, small hands and feet, and genital abnormalities. The symptoms are related to critical chromosome regions including Xq26.1-26.3. In this particular syndrome, no patient with congenital heart disease was previously reported. Here, we report a 6-year-old boy with typical symptoms of Xq25q26 duplication syndrome and double outlet right ventricle (DORV) with pulmonary atresia (PA). He had the common duplicated region of Xq25q26 duplication syndrome extending to the distal region including the MOSPD1 locus. MOSPD1 regulates transforming growth factor beta (TGFß) 2,3 and may be responsible for cardiac development including DORV. In the patient's lymphocytes, mRNA expression of TGFß2 was lower than control, and might cause DORV as it does in TGFß2-deficient mice. Therefore, MOSPD1 is a possible candidate gene for DORV, probably in combination with GPC3. Further studies of the combined functions of MOSPD1 and GPC3 are needed, and identification of additional patients with MOSPD1 and GPC3 duplication should be pursued.

Chromosome Xq28 duplication encompassing MECP2: Clinical and molecular analysis of 16 new patients from 10 families in China.

INTRODUCTION: Chromosome Xq28 duplications encompassing methyl-CpG-binding protein 2 gene (MECP2) are observed most in males with a severe neurodevelopmental disorder associated with hypotonia, spasticity, severe learning disability, delayed psychomotor development, and recurrent pulmonary infections. Most female carriers are asymptomatic due to extremely or completely skewed X-inactivation. METHODS: A retrospective clinical and molecular study was conducted to examine 16 patients and two fetuses from 10 families who were identified among patients with Xq28 duplications who presented at genetic clinics. RESULTS: Of all 16 patients, 10 had a family history. Only one patient was female. All of the patients had no relevant pre-natal history. All of the patients exhibited severe psychomotor developmental delay, infantile hypotonia and recurrent infections. Some of the patients exhibited cardiac abnormalities, gastrointestinal mobility problems, hydrocele of tunica vaginalis, cryptorchidism, and autistic phenotypes. Additionally, neonatal kidney calculus, premature closure of the fontanel and pulmonary sequestration were found in the patients. Duplication sizes in these patients range from 0.21 to 14.391 Mb (most were smaller than 1 Mb), and all the duplications included host cell factor C1 (HCFC1), interleukin-1 receptor-associated kinase 1 (IRAK1), and MECP2. Bioinformatics analysis revealed that approximately half of the distal breakpoints were located within the low-copy repeats (LCRs), which may be involved in the recombination. The two fetuses were found to be healthy in the prenatal diagnosis. CONCLUSION: This is the first large cohort of patients with MECP2 duplication syndrome, including a female, reported in China. Interestingly, neonatal kidney calculus, premature closure of the fontanel and pulmonary sequestration were first reported in this syndrome. However, it was difficult to distinguish if these patients represented unique cases or if these phenotypes can be considered as part of the syndrome. The correlation between the infrequent phenotypes and duplications/genes in the duplication region needs further systematic delineation. In conclusion, our study suggested that it is important to emphasize molecular genetic analysis in patients with developmental delay/intellectual disability and recurrent infections and that it is especially important for familial female carriers to accept prenatal diagnosis.

[Clinical and genetic characteristics of the X chromosome distal long arm microduplications encompassing the MECP2 gene].

OBJECTIVE: Microduplications of the long arm of the X chromosome including the MECP2 gene are relatively common causes of neurodevelopmental disorders in males. Authors analyzed clinical presentations of this disease in children. MATERIAL AND METHODS: Authors performed a clinical and genetic analysis of four cases using contemporary cytogenetic, molecular cytogenetic studies (FISH, array CGH) and X chromosome inactivation analysis. RESULTS AND CONCLUSION: We described somatic, neurologic and mental symptoms of the patients. The genetic imbalance impact on the patients' phenotype, necessity of comprehensive family studies for correct genetic diagnosis and effective genetic counseling in cases of microduplications of the long arm of the X chromosome including the MECP2 gene are discussed.

Positive effects of early androgen therapy on the behavioral phenotype of boys with 47,XXY.

47, XXY occurs in up to 1 in 650 male births and is associated with androgen deficiency, neurodevelopmental delays, and atypical social-behaviors. Previously, we showed that young boys with 47, XXY who received early hormonal therapy (EHT) had significantly improved neurodevelopment. The objective of this follow-up study was to examine the effects of EHT on social behavior in boys with 47, XXY. The study consisted of boys prenatally diagnosed with 47, XXY who were referred for evaluations. Twenty-nine boys received three injections of 25 mg testosterone enanthate and 57 controls did not receive EHT. Behavioral functioning was assessed using the Behavior Rating Inventory of Executive Function, Social Responsiveness Scale, 2nd Ed., and the Child Behavior Checklist for Ages 6-18. The hypothesis that EHT may affect behavior was formulated prior to data collection. Questionnaire data was prospectively obtained and analyzed to test for significance between two groups. Significant differences were identified between group's scores over time in Social Communication (P=0.007), Social Cognition (P=0.006), and Total T-score (P=0.001) on the SRS-2; Initiation (P=0.05) on the BRIEF; and Externalizing Problems (P=0.024), Affective Problems (P=0.05), and Aggressive Behaviors (P=0.031) on the CBCL. This is the third study revealing positive effects of EHT on boys with XXY. There was a significant improvements associated with the 47, XXY genotype in boys who received EHT. Research is underway on the neurobiological mechanisms, and later developmental effects of EHT.

Continuous spikes and waves during slow sleep in a child with karyotype 47, XYY.

The XYY syndrome is a sex chromosome aneuploidy occurring in one of 1,000 live male births. Only few data exist regarding the correlation between this syndrome and epilepsy. An EEG pattern suggestive of benign focal epilepsy with centro-temporal spikes has recently been described in four XYY patients. We report the first patient with XYY trisomy, rolandic spikes, and atypical evolution with continuous spikes and waves during slow sleep (CSWSS). The present report suggests that the association between an EEG pattern similar to that of BECTS and 47, XYY karyotype may not be coincidental. Moreover, we show that an atypical evolution with CSWSS may occur in this chromosomal disorder.

NF-κB signalling requirement for brain myelin formation is shown by genotype/MRI phenotype correlations in patients with Xq28 duplications.

One of the key signals regulating peripheral myelin formation by Schwann cell is the activation of the transcription factor NF-κB. Yet, whether NF-κB exerts similar functions in central myelin formation by oligodendrocytes remains largely unknown. We previously reported white matter abnormalities with unusual discordance between T2 and FLAIR sequences in a patient with intellectual disability and defective NF-κB signalling. These observations prompted us to hypothesise that NF-κB signalling may have a role in the axon myelination process of central neurons. We report here on five male patients with Xq28 duplications encompassing MECP2, three of which presented white matter anomalies on brain MRI. Array-CGH and FISH analyses demonstrated that brain abnormalities correlate with additional copies of the IKBKG, a gene encoding a key regulator of NF-κB activation. Quantitative RT-PCR experiments and κB-responsive reporter gene assays provide evidence that IKBKG overexpression causes impaired NF-κB signalling in skin fibroblasts derived from patients with white matter anomalies. These data further support the role of NF-κB signalling in astroglial cells for normal myelin formation of the central nervous system.

Sex chromosomes and the brain: a study of neuroanatomy in XYY syndrome.

AIM: To assess global and regional brain matter variations associated with XYY syndrome by comparison with Klinefelter syndrome and typical development. METHODS: We used two conceptually distinct voxel-based magnetic resonance imaging methods to examine brain structure in young males with XYY syndrome: (1) volumetric comparison to assess global grey and white matter volumes and (2) support vector machine-based multivariate pattern classification analysis to assess regional neuroanatomy. We assessed verbal, non-verbal, and spatial abilities with the Differential Ability Scales (DAS), and we measured autism diagnostic criteria in eight males with XYY syndrome using the Social Responsiveness Scale and the Autism Diagnostic Interview-Revised (ADI-R). RESULTS: A comparison of 36 typically developing males (mean age 11 y, SD 1 y 9 mo), 31 males with Klinefelter syndrome (mean age 9 y 8 mo, SD 1 y 8 mo), and eight males with XYY syndrome (mean age 11 y 6 mo, SD 1 y 11 mo) showed that total white and grey matter volumes were significantly, or nearly significantly, higher in males with XYY syndrome than in males belonging to the other two groups (grey matter: XYY males vs typically developing males, p<0.006; XYY vs males with Klinefelter syndrome, p<0.001; white matter: XYY males vs typically developing males, p=0.061; XYY males vs males with Klinefelter syndrome, p=0.004). Voxel-based multivariate pattern classification analysis indicates that, after controlling for global volumes, regional brain variations in XYY syndrome are more like those found in Klinefelter syndrome than those occurring in typical development. Further, visualization of classification parameters suggests that insular and frontotemporal grey matter and white matter, including known language areas, are reduced in males with XYY syndrome, similar to what is seen in Klinefelter syndrome. In males with XYY syndrome, DAS verbal and non-verbal scores were significantly lower than in typically developing participants (both p<0.001). DAS scores were not significantly different between XYY and Klinefelter syndrome groups. In five of eight males with XYY syndrome, the Social Responsiveness Scale score exceeded the cut-off for a likely diagnosis of autism spectrum disorder (ASD). In three of eight males with XYY syndrome, the ADI-R score met the cut-off for ASD diagnosis; in another two, ADI-R scores within the social and communication domains met the cut-off values for a diagnosis of ASD. INTERPRETATION: The results suggest that genetic variations associated with XYY syndrome result in increased brain matter volumes, a finding putatively related to the increased frequency of ASDs in individuals with this condition. In addition, frontotemporal grey and white matter reductions in XYY syndrome provide a likely neuroanatomical correlate for observed language impairments.

A preliminary study of the relationship between the long arm of the Y chromosome (Yqh+) and reproductive outcomes in IVF/ICSI-ET.

OBJECTIVE: To compare the reproductive outcomes of Yqh+-carrying and control couples undergoing IVF/ICSI treatments. STUDY DESIGN: Retrospective analysis of 72 Yqh+ carriers and 986 Yqh+ non-carriers undergoing their first cycle of ART in a single centre between August 2005 and May 2011. RESULTS: Yqh+ carrying couples had significantly worse reproductive outcomes compared with control couples undergoing IVF treatment. There were a significantly higher cancellation rate (20.69% vs 7.9%; P<0.05; OR, 3.03; CI, 1.18-7.79) and a significant lower fertilisation rate (50.05% vs 66.01%; P<0.05; OR, 0.61; CI, 0.49-0.57), implantation rate (8.33% vs 20.87%; P<0.05; OR, 0.35; CI, 0.14-0.87), good quality embryo ratio (44.70% vs 57.89%; P<0.05; OR, 0.59; CI, 0.43-0.80) and clinical pregnancy rate (17.39% vs 39.59%; P<0.05; OR, 0.32; CI, 0.11-0.96) in Yqh+ group compared with control group undergoing IVF treatment. Yqh+ carrying couples had similar reproductive outcomes compared with control couples undergoing ICSI treatment. CONCLUSIONS: The Y chromosome polymorphic variant Yqh+ most likely plays a role in infertility. Yqh+ couples with poor reproductive outcomes in IVF treatment can be advised to undergo ICSI to improve their reproductive results in the next cycle.

Biological aspects of gender disorders.

The scientific community is very interested in the biological aspects of gender disorders and sexual orientation. There are different levels to define an individual's sex: chromosomal, gonadic, and phenotypic sex. Concerning the psychological sex, men and women are different by virtue of their own gender identity, which means they recognize themselves as belonging to a determinate sex. They are different also as a result of their own role identity, a set of behaviors, tendencies, and cognitive and emotional attitudes, commonly defined as "male" and "female". Transsexuality is a disorder characterized by the development of a gender identity opposed to phenotypic sex, whereas homosexuality is not a disturbance of gender identity but only of sexual attraction, expressing sexual orientation towards people of the same sex. We started from a critical review of literature on genetic and hormonal mechanisms involved in sexual differentiation. We re-examined the neuro-anatomic and functional differences between men and women, with special reference to their role in psychosexual differentiation and to their possible implication in the genesis of homosexuality and identity gender disorders. Homosexuality and transsexuality are conditions without a well defined etiology. Although the influence of educational and environmental factors in humans is undeniable, it seems that organic neurohormonal prenatal and postnatal factors might contribute in a determinant way in the development of these two conditions. This "organicistic neurohormal theory" might find support in the study of particular situations in which the human fetus is exposed to an abnormal hormonal environment in utero.

Mouse models for evaluating sex chromosome effects that cause sex differences in non-gonadal tissues.

XX and XY cells have a different number of X and Y genes. These differences in their genomes cause sex differences in the functions of cells, both in the gonads and in non-gonadal tissues. This review discusses mouse models that have shed light on these direct genetic effects of sex chromosomes that cause sex differences in physiology. Because many sex differences in tissues are caused by different effects of male and female gonadal hormones, it is important to attempt to discriminate between direct genetic and hormonal effects. Numerous mouse models exist in which the number of X or Y genes is manipulated, aiming to observe the effects on phenotype. In two models, namely the four core genotypes model and SF1 knockout gonadless mice, it is possible to detect sex chromosome effects that are not explained by group differences in gonadal hormones. Moreover, mouse models are available to determine whether the sex chromosome effects are caused by X or Y genes.

[Normal and deviating puberty in boys]. / Normal och avvikande pubertet hos pojkar.

BACKGROUND: Onset of puberty in boys is more complex than in girls, and delayed onset is the most common puberty complication in boys. This article presents the physiology of normal development of male puberty and the background for commonly associated disturbances. MATERIAL AND METHOD: The article builds on clinical experience and relevant publications within pediatric endocrinology. RESULTS AND INTERPRETATION: Mechanisms involved in pubertal development of gonads remain unclear despite intensive research. Height growth as well as the age for onset of puberty are influenced by environmental factors. Genetic factors are however more important determinants within a defined population and one usually inherits the probability for both early and delayed puberty. Gonadotropin releasing hormone (GnRH) neurons in the hypothalamus secrete GnRH in intermittent pulses to the pituitary glands that respond with pulsatile LH and FSH production. These neurons are thus decisive for testicle activity and therefore puberty development. GnRH-neurons are inactive during childhood because many types of hypothalamic neurons suppress them. Puberty starts when this suppression is reduced and kisspeptin-producing neurons stimulate GnRH neuron activity. At a testicle volume of 4 mL the Leydig cells' testosterone production has reached such a level that pubertal changes become apparent. Delayed or incomplete puberty sometimes occurs in certain syndromes, and complete lack of puberty can also be syndrome-related. Klinefelter's syndrome is associated with gonad dysgenesis expressed as gradual reduction of gonadal function starting after puberty. Cancer treatment during childhood; especially radiation therapy of the gonads, may cause hypogonadism and infertility. It is therefore essential to follow gonad function closely in these patients. In conclusion, each doctor treating children should be able to evaluate the degree of puberty development and when needed request adequate laboratory tests.