Contiguous gene syndrome due to an interstitial deletion in Xp22.3 in a boy with ichthyosis, chondrodysplasia punctata, mental retardation and ADHD

STS and PUDP Deletion Identified by Targeted Panel Sequencing with CNV Analysis in X-Linked Ichthyosis: A Case Report and Literature Review

X-linked recessive ichthyosis (XLI) is clinically characterized by dark brown, widespread dryness with polygonal scales. We describe the identification of STS and PUDP deletions using targeted panel sequencing combined with copy-number variation (CNV) analysis in XLI. A 9-month-old infant was admitted for genetic counseling. Since the second day after birth, the infant's skin tended to be dry and polygonal scales had accumulated over the abdomen and upper extremities. The infant's maternal uncle and brother (who had also exhibited similar skin symptoms from birth) presented with polygonal scales on their trunks. CNV analysis revealed a hemizygous deletion spanning 719.3 Kb on chromosome Xp22 (chrX:7,108,996-7,828,312), which included a segment of the STS gene and exhibited a Z ratio of -2 in the proband. Multiplex ligation-dependent probe amplification (MLPA) confirmed this interstitial Xp22.31 deletion. Our report underscores the importance of implementing CNV screening techniques, including sequencing data analysis and gene dosage assays such as MLPA, to detect substantial deletions that encompass the STS gene region of Xq22 in individuals suspected of having XLI.

Xp22.31 copy number variations in 87 fetuses: refined genotype-phenotype correlations by prenatal and postnatal follow-up

BACKGROUND

Xp22.31 deletion and duplication have been described in various studies, but different laboratories interpret pathogenicity differently.

OBJECTIVES

Our study aimed to refine the genotype-phenotype associations between Xp22.31 copy number variants in fetuses, with the aim of providing data support to genetic counseling.

METHODS

We retrospectively analyzed karyotyping and single nucleotide polymorphism array results from 87 fetuses and their family members. Phenotypic data were obtained through follow-up visits.

RESULTS

The percentage of fetuses carrying the Xp22.31 deletions (9 females, 12 males) was 24.1% (n = 21), while duplications (38 females, 28 males) accounted for 75.9% (n = 66). Here, we noted that the typical region (from 6.4 to 8.1 Mb, hg19) was detected in the highest ratio, either in the fetuses with deletions (76.2%, 16 of 21) or duplications (69.7%, 46 of 66). In female deletion carriers, termination of pregnancy was chosen for two fetuses, and the remaining seven were born without distinct phenotypic abnormalities. In male deletion carriers, termination of pregnancy was chosen for four fetuses, and the remaining eight of them displayed ichthyosis without neurodevelopmental anomalies. In two of these cases, the chromosomal imbalance was inherited from the maternal grandfathers, who also only had ichthyosis phenotypes. Among the 66 duplication carriers, two cases were lost at follow-up, and pregnancy was terminated for eight cases. There were no other clinical findings in the rest of the 56 fetuses, including two with Xp22.31 tetrasomy, for either male or female carriers.

CONCLUSION

Our observations provide support for genetic counseling in male and female carriers of Xp22.31 copy number variants. Most of them are asymptomatic in male deletion carriers, except for skin findings. Our study is consistent with the view that the Xp22.31 duplication may be a benign variant in both sexes.

Kallmann Syndrome and X-linked Ichthyosis Caused by Translocation Between Chromosomes X and Y: A Case Report

Background

Xp22.3 region is characterized by low frequency of interspersed repeats and low GC content. Several clinically important genes including ANOS1 (KAL1) reside in this region. This gene was first identified due to translocation between chromosomes X and Y in a patient with Kallmann syndrome.

Case Presentation

A 20 year old male presented with complaints of delayed secondary sexual characteristics, impaired sense of smell, and poor scholastic performance. On examination, he had short stature (151 cm; <3rd centile). His sexual maturity corresponded to Tanner stage 3. Stretched penile length was 3.6 cm (<3rd centile). Right testis was undescended with low left testicular volume (12 ml). There was mild ichthyosis over abdomen and back. He had hyposmia, hoarse voice, and synkinesia. Investigations were suggestive of hypogonadotrophic hypogonadism. Karyotype revealed an extra chromosomal material on p arm of chromosome X (46,Xp+,Y). On cytogenetic microarray, deletion of 8.3 Mb on Xp22.33 region and duplication of 12.8 Mb on Yq11.22 region were identified. The breakpoint on X chromosome resulted in deletion of exons 7-14 of ANOS1 gene and complete STS, NLGN4X, ARSL (ARSE), SHOX, and VCX genes.

Conclusion

Patients diagnosed with Kallmann syndrome should receive careful clinical evaluation to detect presence of a contiguous gene syndrome.

Klinefelter's Syndrome with Maternal Uniparental Disomy X, Interstitial Xp22.31 Deletion, X-linked Ichthyosis, and Severe Central Nervous System Regression

We presented in this article a patient with Klinefelter syndrome (KS) (47,XXY) who had maternal nondisjunction and uniparental disomy of the X chromosome with regions of heterodisomy and isodisomy, an interstitial Xp22.31 deletion of both X chromosomes, and other problems. His mother also possesses the same Xp22.31 deletion. The patient presented with status epilepticus and stroke, followed by severe brain atrophy and developmental regression. His unusual clinical and cytogenetic findings apparently have not been reported with either KS or Xp22.31 deletions. Based on the patient's available genetic and biochemical information, we cannot satisfactorily explain his seizures, strokes, or catastrophic brain regression.

Genetic polymorphism analyses of three novel X chromosomal short tandem repeat loci in the Xp22.3 region

X chromosomal short tandem repeats (X-STRs) can be useful for haplotype analysis in DNA testing, particularly for complex kinship testing or when one parent is absent. We searched downstream of four previously detected loci in the Xp22.3 region (LC149476, LC149479, LC149480, and LC149484) and detected and analyzed three novel short tandem repeats (STRs), LC317283, LC317284, and LC317285, with the repeat sequences TATAA, TTTA, and TATC, respectively. The forensic statistical values in Japanese subjects were confirmed to be noninferior to existing loci, with values for polymorphism information content, the power of discrimination in males (PDm), and the power of discrimination in females (PDf) of 0.5606-0.7448, 0.6078-0.7774, and 0.7990-0.9178, respectively. Haplotype analysis also revealed linkage disequilibrium between LC317283 and the four known loci (LC149476, LC149479, LC149480, and LC149484) and between two other novel loci (LC317284 and LC317285). Analysis of three family samples suggested that these STRs could be useful in complex kinship testing, so we developed an X-STR multiplex polymerase chain reaction (PCR) system for the seven loci and confirmed its ability to provide favorable amplification. We anticipate that the identified loci and developed multiplex PCR system will be beneficial to the field of forensic medicine.

A prenatal diagnosis and genetics study of five pedigrees in the Chinese population with Xp22.31 microduplication

Background

Copy number variations (CNVs) can contribute to human phenotype, phenotypic diversity and disease susceptibility, while others may benign. In the current study, an attempt to investigate the pathogenicity of CNVs in chromosome Xp22.31 was explored.

Methods

G-banding and SNP-array techniques were used to analyze chromosome karyotypes and CNVs in fetuses. Parents associate with five different pedigrees possessing high risk factors in pregnancy were considered with such parameters as advanced age, high risk of serological screening and ultrasound abnormalities.

Results

The fetuses’ amniotic fluid karyotypes were 46, XX and those of their parents with the five pedigrees revealed no abnormalities. Here, we noticed a series of individuals with Xp22.31 duplications ranging from 534.6 kb to 1.6 Mb. It was detected through SNP array that the fetuses in Pedigree 1 and 2 had ~ 600 kb duplications in the Xp22.31 region of their X chromosomes which contained two OMIM genes, HDHD1 (OMIM: 306480) and part of STS (OMIM: 300747). The fetuses of Pedigrees 3, 4 and 5 had 1.6 Mb duplication in the same chromosome which contained four OMIM genes: HDHD1 (OMIM: 306480), STS (OMIM: 300747), PNPLA4 (OMIM: 300102) and VCX (OMIM: 300229). The duplications in the fetuses of Pedigrees 1 and 5 were inherited from the non-phenotypic parents. Pedigrees 3 and 4 refused to perform parental verification. Finally, four of the five pedigrees continue towards pregnancy with no abnormalities being observed during followed-ups.

Conclusion

Our study first showed duplications of Xp22.31 in Chinese population. Clinical and genetic investigation on five different pedigrees, we consider the duplication of these fragments as likely benign copy number variants (CNVs). We suggest that the duplications of Xp22.31 with recurrent duplication as a benign CNVs .

Obesity and Hypogonadism-A Narrative Review Highlighting the Need for High-Quality Data in Adolescents

The prevalence of obesity continues to rise in adult and pediatric populations throughout the world. Obesity has a direct impact on all organ systems, including the reproductive system. This review summarizes current knowledge about the effects of obesity on the male reproductive system across age, highlighting the need for more data in children and adolescents. Male hypogonadism is commonly seen in patients with obesity and affects the onset, duration, and progression of puberty. Different pathophysiologic mechanisms include increased peripheral conversion of testosterone to estrone and increased inflammation due to increased fat, both of which lead to suppression of the hypothalamic-pituitary-gonadotropin (HPG) axis and delayed development of secondary sexual characteristics in adolescent males. Evaluation of the HPG axis in obesity includes a thorough history to exclude other causes of hypogonadism and syndromic associations. Evaluation should also include investigating the complications of low testosterone, including increased visceral fat, decreased bone density, cardiovascular disease risk, and impaired mood and cognition, among others. The mainstay of treatment is weight reduction, but medications such as testosterone and clomiphene citrate used in adults, remain scarcely used in adolescents. Male hypogonadism associated with obesity is common and providers who care for adolescents and young adults with obesity should be aware of its impact and management.

X-linked icthyosis and neurodevelopmental disorders: A case report and review of literature

The genetics of neurodevelopmental disorders have long intrigued clinicians and researchers alike. In this case report, we report a rare case of neurodevelopmental disorders associated with icthyosis with an underlying SHOX (short stature homeobox) gene mutation.

Behavioural and Psychiatric Phenotypes in Men and Boys with X-Linked Ichthyosis: Evidence from a Worldwide Online Survey

BACKGROUND

X-linked ichthyosis (XLI) is a rare dermatological condition arising from deficiency for the enzyme steroid sulfatase (STS). Preliminary evidence in boys with XLI, and animal model studies, suggests that individuals lacking STS are at increased risk of developmental disorders and associated traits. However, the behavioural profile of children with XLI is poorly-characterised, and the behavioural profile of adults with XLI has not yet been documented at all.

MATERIALS AND METHODS

Using an online survey, advertised worldwide, we collected detailed self- or parent-reported information on behaviour in adult (n = 58) and younger (≤18yrs, n = 24) males with XLI for comparison to data from their non-affected brothers, and age/gender-matched previously-published normative data. The survey comprised demographic and background information (including any prior clinical diagnoses) and validated questionnaires assaying phenotypes of particular interest (Adult ADHD Self-Report Scale v1.1, Barrett Impulsiveness Scale-11, adult and adolescent Autism Quotient, Kessler Psychological Distress Scales, and Disruptive Behaviour Disorder Rating Scale).

RESULTS

Individuals with XLI generally exhibited normal sensory function. Boys with XLI were at increased risk of developmental disorder, whilst adults with the condition were at increased risk of both developmental and mood disorders. Both adult and younger XLI groups scored significantly more highly than male general population norms on measures of inattention, impulsivity, autism-related traits, psychological distress and disruptive behavioural traits.

CONCLUSIONS

These findings indicate that both adult and younger males with XLI exhibit personality profiles that are distinct from those of males within the general population, and suggest that individuals with XLI may be at heightened risk of psychopathology. The data are consistent with the notion that STS is important in neurodevelopment and ongoing brain function, and with previous work suggesting high rates of developmental disorders in boys with XLI. Our results suggest that individuals with XLI may require medical care from multidisciplinary teams, and should help to inform genetic counselling for the condition.

Using Sibling Designs to Understand Neurodevelopmental Disorders: From Genes and Environments to Prevention Programming

Neurodevelopmental disorders represent a broad class of childhood neurological conditions that have a significant bearing on the wellbeing of children, families, and communities. In this review, we draw on evidence from two common and widely studied neurodevelopmental disorders-autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD)-to demonstrate the utility of genetically informed sibling designs in uncovering the nature and pathogenesis of these conditions. Specifically, we examine how twin, recurrence risk, and infant prospective tracking studies have contributed to our understanding of genetic and environmental liabilities towards neurodevelopmental morbidity through their impact on neurocognitive processes and structural/functional neuroanatomy. It is suggested that the siblings of children with ASD and ADHD are at risk not only of clinically elevated problems in these areas, but also of subthreshold symptoms and/or subtle impairments in various neurocognitive skills and other domains of psychosocial health. Finally, we close with a discussion on the practical relevance of sibling designs and how these might be used in the service of early screening, prevention, and intervention efforts that aim to alleviate the negative downstream consequences associated with disorders of neurodevelopment.

Birth of a boy with isolated short stature after prenatal diagnosis of a Xp22.3 nullosomy due to an inherited t(X;15) (p22.3;p10) translocation

Key Clinical Message

Translocations between X and acrocentric chromosomes are rare. We report on the inheritance of a familial t(X;15)(p22.3;p10) translocation in a fetus referred for short long bones. Cytogenetic analysis revealed an unbalanced translocation combined with a three-gene nullosomy. After genetic counseling, a prognosis was established and a healthy boy was delivered.

Sex differences in attention Deficit Hyperactivity Disorder: candidate genetic and endocrine mechanisms

Attention Deficit Hyperactivity Disorder (ADHD) is a developmental condition characterised by severe inattention, pathological impulsivity and hyperactivity; it is relatively common affecting up to 6% of children, and is associated with a risk of long-term adverse educational and social consequences. Males are considerably more likely to be diagnosed with ADHD than females; the course of the disorder and its associated co-morbidities also appear to be sensitive to sex. Here, I discuss fundamental biological (genetic and endocrine) mechanisms that have been shown to, or could theoretically, contribute towards these sexually dimorphic phenomena. Greater understanding of how and why the sexes differ with respect to ADHD vulnerability should allow us to identify and characterise novel protective and risk factors for the disorder, and should ultimately facilitate improved diagnosis, prognosis and treatment.

Biological mechanisms associated with increased perseveration and hyperactivity in a genetic mouse model of neurodevelopmental disorder

Chromosomal deletions at Xp22.3 appear to influence vulnerability to the neurodevelopmental disorders attention deficit hyperactivity disorder (ADHD) and autism. 39,X(Y*)O mice, which lack the murine orthologue of the Xp22.3 ADHD candidate gene STS (encoding steroid sulfatase), exhibit behavioural phenotypes relevant to such disorders (e.g. hyperactivity), elevated hippocampal serotonin (5-HT) levels, and reduced serum levels of dehydroepiandrosterone (DHEA). Here we initially show that 39,X(Y*)O mice are also deficient for the recently-characterised murine orthologue of the Xp22.3 autism candidate gene ASMT (encoding acetylserotonin-O-methyltransferase). Subsequently, to specify potential behavioural correlates of elevated hippocampal 5-HT arising due to the genetic lesion, we compared 39,X(Y*)O MF1 mice to 40,XY MF1 mice on behavioural tasks taxing hippocampal and/or 5-HT function (a 'foraging' task, an object-location task, and the 1-choice serial reaction time task of impulsivity). Although Sts/Asmt deficiency did not influence foraging behaviour, reactivity to familiar objects in novel locations, or 'ability to wait', it did result in markedly increased response rates; these rates correlated with hippocampal 5-HT levels and are likely to index behavioural perseveration, a frequent feature of neurodevelopmental disorders. Additionally, we show that whilst there was no systematic relationship between serum DHEA levels and hippocampal 5-HT levels across 39,X(Y*)O and 40,XY mice, there was a significant inverse linear correlation between serum DHEA levels and activity. Our data suggest that deficiency for genes within Xp22.3 could influence core behavioural features of neurodevelopmental disorders via dissociable effects on hippocampal neurochemistry and steroid hormone levels, and that the mediating neurobiological mechanisms may be investigated in the 39,X(Y*)O model.

Cognitive, behavioural and psychiatric phenotypes associated with steroid sulfatase deficiency

The enzyme steroid sulfatase (STS) desulfates a variety of steroid compounds thereby altering their activity. STS is expressed in the skin, and its deficiency in this tissue has been linked to the dermatological condition X-linked ichthyosis. STS is also highly expressed in the developing and adult human brain, and in a variety of steroidogenic organs (including the placenta and gonads); therefore it has the potential to influence brain development and function directly and/or indirectly (through influencing the hormonal milieu). In this review, we first discuss evidence from human and animal model studies suggesting that STS deficiency might predispose to neurobehavioural abnormalities and certain psychiatric disorders. We subsequently discuss potential mechanisms that may underlie these vulnerabilities. The data described herein have potential implications for understanding the complete spectrum of clinical phenotypes associated with X-linked ichthyosis, and may indicate novel pathogenic mechanisms underlying psychological dysfunction in developmental disorders such as attention deficit hyperactivity disorder and Turner syndrome.

A case of 9.7 Mb terminal Xp deletion including OA1 locus associated with contiguous gene syndrome

Terminal or interstitial deletions of Xp (Xp22.2→Xpter) in males have been recognized as a cause of contiguous gene syndromes showing variable association of apparently unrelated clinical manifestations such as Leri-Weill dyschondrosteosis (SHOX), chondrodysplasia punctata (CDPX1), mental retardation (NLGN4), ichthyosis (STS), Kallmann syndrome (KAL1), and ocular albinism (GPR143). Here we present a case of a 13.5 yr old boy and sister with a same terminal deletion of Xp22.2 resulting in the absence of genes from the telomere of Xp to GPR143 of Xp22. The boy manifested the findings of all of the disorders mentioned above. We began a testosterone enanthate monthly replacement therapy. His sister, 11 yr old, manifested only Leri-Weill dyschondrosteosis, and had engaged in growth hormone therapy for 3 yr. To the best of our knowledge, this is the first report of a male with a 9.7 Mb terminal Xp deletion including the OA1 locus in Korea.

Sex chromosomes and sex chromosome abnormalities

This article focuses on constitutional sex chromosome abnormalities detected by conventional cytogenetics and fluorescence in situ hybridization. The author discusses the two general classifications of abnormalities: numerical and structural. Also included are descriptions of unique aspects of X and Y chromosomes, technological advances in detection, and future perspectives.

Altered serotonergic function may partially account for behavioral endophenotypes in steroid sulfatase-deficient mice

The X-linked gene STS encodes the steroid hormone-modulating enzyme steroid sulfatase. Loss-of-function of STS, and variation within the gene, have been associated with vulnerability to developing attention deficit hyperactivity disorder (ADHD), a neurodevelopmental condition characterized by inattention, severe impulsivity, hyperactivity, and motivational deficits. ADHD is commonly comorbid with a variety of disorders, including obsessive-compulsive disorder. The neurobiological role of steroid sulfatase, and therefore its potential role in ADHD and associated comorbidities, is currently poorly understood. The 39,X(Y)*O mouse, which lacks the Sts gene, exhibits several behavioral abnormalities relevant to ADHD including inattention and hyperactivity. Here, we show that, unexpectedly, 39,X(Y)*O mice achieve higher ratios than wild-type mice on a progressive ratio (PR) task thought to index motivation, but that there is no difference between the two groups on a behavioral task thought to index compulsivity (marble burying). High performance liquid chromatography analysis of monoamine levels in wild type and 39,X(Y)*O brain tissue regions (the frontal cortex, striatum, thalamus, hippocampus, and cerebellum) revealed significantly higher levels of 5-hydroxytryptamine (5-HT) in the striatum and hippocampus of 39,X(Y)*O mice. Significant correlations between hippocampal 5-HT levels and PR performance, and between striatal 5-HT levels and locomotor activity strongly implicate regionally-specific perturbations of the 5-HT system as a neurobiological candidate for behavioral differences between 40,XY and 39,X(Y)*O mice. These data suggest that inactivating mutations and functional variants within STS might exert their influence on ADHD vulnerability, and disorder endophenotypes through modulation of the serotonergic system.

ADHD and genetic syndromes

A high rate of Attention Deficit/Hyperactivity Disorder (ADHD)-like characteristics has been reported in a wide variety of disorders including syndromes with known genetic causes. In this article, we review the genetic and the neurobiological links between ADHD symptoms and some genetic syndromes such as: Fragile X Syndrome, Neurofibromatosis 1, DiGeorge Syndrome, Tuberous Sclerosis Complex, Turner Syndrome, Williams Syndrome and Klinefelter Syndrome. Although each syndrome may arise from different genetic abnormalities with multiple molecular functions, the effects of these abnormalities may give rise to common effects downstream in the biological pathways or neural circuits, resulting in the presentation of ADHD symptoms. Early diagnosis of ADHD allows for earlier treatment, and has the potential for a better outcome in children with genetic syndromes.

Clinical implementation of whole-genome array CGH as a first-tier test in 5080 pre and postnatal cases

Background

Array comparative genomic hybridization (CGH) is currently the most powerful method for detecting chromosomal alterations in pre and postnatal clinical cases. In this study, we developed a BAC based array CGH analysis platform for detecting whole genome DNA copy number changes including specific micro deletion and duplication chromosomal disorders. Additionally, we report our experience with the clinical implementation of our array CGH analysis platform. Array CGH was performed on 5080 pre and postnatal clinical samples from patients referred with a variety of clinical phenotypes.

Results

A total of 4073 prenatal cases (4033 amniotic fluid and 40 chorionic villi specimens) and 1007 postnatal cases (407 peripheral blood and 600 cord blood) were studied with complete concordance between array CGH, karyotype and fluorescence in situ hybridization results. Among 75 positive prenatal cases with DNA copy number variations, 60 had an aneuploidy, seven had a deletion, and eight had a duplication. Among 39 positive postnatal cases samples, five had an aneuploidy, 23 had a deletion, and 11 had a duplication.

Conclusions

This study demonstrates the utility of using our newly developed whole-genome array CGH as first-tier test in 5080 pre and postnatal cases. Array CGH has increased the ability to detect segmental deletion and duplication in patients with variable clinical features and is becoming a more powerful tool in pre and postnatal diagnostics.

Steroid sulfatase is a potential modifier of cognition in attention deficit hyperactivity disorder

Deletions encompassing the X-linked STS gene (encoding steroid sulfatase) have been observed in subjects with neurodevelopmental disorders, including attention deficit hyperactivity disorder (ADHD). Recently, two single nucleotide polymorphisms (SNPs) within STS (rs12861247 and rs17268988) have been reported to be associated with ADHD risk and inattentive symptoms in ADHD, respectively. Using a UK sample of ADHD subjects (aged 5-18 years), we tested the hypothesis that rs12861247 is associated with ADHD risk using a case-control approach (comparing 327 ADHD cases with 358 male controls from the Wellcome Trust Case Control Consortium). Using a subset of males from the ADHD sample, we also examined whether variation within STS is associated with symptomatology/cognitive function in ADHD. We then tested whether SNPs associated with cognitive function in ADHD were also associated with cognitive function in healthy male subjects using a German sample (n = 143, aged 18-30 years), and whether STS was expressed in brain regions pertinent to ADHD pathology during development. We did not replicate the previously identified association with rs12861247. However, in ADHD males, variation at rs17268988 was associated with inattentive symptoms, while variation within STS was significantly associated with performance on three cognitive measures. Three SNPs associated with cognitive function in ADHD males were not associated with cognitive function in healthy males. STS was highly expressed in the developing cerebellar neuroepithelium, basal ganglia, thalamus, pituitary gland, hypothalamus and choroid plexus. These data suggest that genetic variants affecting STS expression and/or activity could influence the function of brain regions perturbed in ADHD.

Familial X;Y translocation with distinct phenotypic consequences: Characterization using FISH and array CGH

X;Y translocation is a relatively rare event in humans. Analyzed cytogenetically, the majority of these aberrations have breakpoints at Xp22 and Yq11. Females with t(X;Y)(p22;q11) are phenotypically normal except for short stature, while the males may have abnormalities. Aberrations that lead to nullisomy of the deleted region and complete loss of the respective genes have been recognized as a cause of variable contiguous gene syndromes in males. The phenotype depends on the extent and position of the deletion showing the variable association of apparently unrelated clinical manifestations such as ichthyosis, chondrodysplasia punctata, hypogonadotropic hypogonadism with anosmia, ocular albinism, short stature, and mental retardation. In addition, some patients have been reported with symptoms of attention deficit hyperactivity disorder. The extent of terminal Xp deletions is limited by the presence of male lethal genes in Xp22.2 at about 10-11 Mb from the telomere. The deletions in the majority of viable reported male patients extend to the STS ( approximately 7.0 Mb) or to the KAL1 ( approximately 8.5 Mb) loci. We present a clinical, cytogenetic, FISH, and array CGH study of a family with an Xp;Yq translocation. The chromosomal status is also discussed in the light of their phenotypic traits. The final karyotypes of the patients were designated as: Patient 1: 46,Y,der(X),t(X;Y)(p22;q12).ish der(X)(Xpter-,DXZ1+,Xqter+)mat.arr cgh Xp22.31p22.33(RP11-60P14 --> RP13-391G2)x0;arr cgh Yq11.221qter (RP11-235I1 --> RP11-270H4)x2.Patient 2: 46,X,der(X),t(X;Y)(p22;q12).ish der(X)(Xpter-,DXZ1+,Xqter+)mat.arr cgh Xp22.31p22.33(RP11-60P14 --> RP13-391G2)x1;arr cgh Yq11.221qter (RP11-235I1 --> RP11-270H4)x1.

Systematic genotype-phenotype analysis of autism susceptibility loci implicates additional symptoms to co-occur with autism

Many genetic studies in autism have been performed, resulting in the identification of multiple linkage regions and cytogenetic aberrations, but little unequivocal evidence for the involvement of specific genes exists. By identifying novel symptoms in these patients, enhanced phenotyping of autistic individuals not only improves understanding and diagnosis but also helps to define biologically more homogeneous groups of patients, improving the potential to detect causative genes. Supported by recent copy number variation findings in autism, we hypothesized that for some susceptibility loci, autism resembles a contiguous gene syndrome, caused by aberrations within multiple (contiguous) genes, which jointly increases autism susceptibility. This would result in various different clinical manifestations that might be rather atypical, but that also co-occur with autism. To test this hypothesis, 13 susceptibility loci, identified through genetic linkage and cytogenetic analyses, were systematically analyzed. The Online Mendelian Inheritance in Man database was used to identify syndromes caused by mutations in the genes residing in each of these loci. Subsequent analysis of the symptoms expressed within these disorders allowed us to identify 33 symptoms (significantly more than expected, P=0.037) that were over-represented in previous reports mapping to these loci. Some of these symptoms, including seizures and craniofacial abnormalities, support our hypothesis as they are already known to co-occur with autism. These symptoms, together with ones that have not previously been described to co-occur with autism, might be considered for use as inclusion or exclusion criteria toward defining etiologically more homogeneous groups for molecular genetic studies of autism.

Converging pharmacological and genetic evidence indicates a role for steroid sulfatase in attention

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder characterized by deficits in attention, increased motor impulsivity, and hyperactivity. Preliminary work in mice and humans has suggested the X-linked gene STS (which encodes the enzyme steroid sulfatase) as a mediator of attentional functioning and as a candidate gene for ADHD.

METHODS

The effects of modulating the murine steroid sulfatase axis pharmacologically (through administration of the substrate dehydroepiandrosterone sulfate [DHEAS], 0-40 mg/kg, or acute inhibition of the enzyme by COUMATE, 10mg/kg) or genetically (through loss of the gene in 39,X(Y)*O mice) were assayed using the 5-choice serial reaction time task (5-CSRTT) a test of visuospatial attention and response control, and a locomotor activity paradigm.

RESULTS

DHEAS administration improved 5-CSRTT performance under attentionally demanding conditions, whereas steroid sulfatase inhibition impaired accuracy under the same conditions. Loss of Sts expression constitutively throughout development in 39,X(Y)*O mice resulted in deficits in 5-CSRTT performance at short stimulus durations and reduced anticipatory responding. Neither the pharmacologic nor the genetic manipulations affected basic locomotor activity.

CONCLUSIONS

These data provide converging evidence indicating a role for steroid sulfatase in discrete aspects of attentional functioning and are suggestive of a role in motor impulsivity. The findings provide novel insights into the neurobiology of attention and strengthen the notion of STS as a candidate gene for the attentional component of ADHD.

The genetic overlap of attention deficit hyperactivity disorder and autistic spectrum disorder

Autistic spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD) are classified as distinct disorders within the DSM-IV-TR (1994). The manual excludes simultaneous use of both diagnoses in case of overlap on a symptomatic level. However this does not always represent clinical observations and findings of previous studies. This review explores the genetic basis of the phenomenological overlap between ADHD and ASD. Based on an extensive review of twin-, linkage-, association studies, and reported structural genomic abnormalities associated with these disorders, we have identified seventeen regions on the human genome that can be related to both disorders. These regions of shared genetic association are: 2q35, 3p14, 4p16.1, 4p16.3, 5p15.31, 5p15.33, 7p12.3, 7p22, 7q21, 8q24.3, 14q12, 15q11–12, 16p13, 17q11, 18q21–23, 22q11.2, Xp22.3. The presented data are of interest for future genetic studies and appear to suggest the existence of a phenotype partition that may differ from the current classification of psychiatric disorders.