Preference for biological motion is reduced in ASD: implications for clinical trials and the search for biomarkers.

BACKGROUND: The neurocognitive mechanisms underlying autism spectrum disorder (ASD) remain unclear. Progress has been largely hampered by small sample sizes, variable age ranges and resulting inconsistent findings. There is a pressing need for large definitive studies to delineate the nature and extent of key case/control differences to direct research towards fruitful areas for future investigation. Here we focus on perception of biological motion, a promising index of social brain function which may be altered in ASD. In a large sample ranging from childhood to adulthood, we assess whether biological motion preference differs in ASD compared to neurotypical participants (NT), how differences are modulated by age and sex and whether they are associated with dimensional variation in concurrent or later symptomatology. METHODS: Eye-tracking data were collected from 486 6-to-30-year-old autistic (N = 282) and non-autistic control (N = 204) participants whilst they viewed 28 trials pairing biological (BM) and control (non-biological, CTRL) motion. Preference for the biological motion stimulus was calculated as (1) proportion looking time difference (BM-CTRL) and (2) peak look duration difference (BM-CTRL). RESULTS: The ASD group showed a present but weaker preference for biological motion than the NT group. The nature of the control stimulus modulated preference for biological motion in both groups. Biological motion preference did not vary with age, gender, or concurrent or prospective social communicative skill within the ASD group, although a lack of clear preference for either stimulus was associated with higher social-communicative symptoms at baseline. LIMITATIONS: The paired visual preference we used may underestimate preference for a stimulus in younger and lower IQ individuals. Our ASD group had a lower average IQ by approximately seven points. 18% of our sample was not analysed for various technical and behavioural reasons. CONCLUSIONS: Biological motion preference elicits small-to-medium-sized case-control effects, but individual differences do not strongly relate to core social autism associated symptomatology. We interpret this as an autistic difference (as opposed to a deficit) likely manifest in social brain regions. The extent to which this is an innate difference present from birth and central to the autistic phenotype, or the consequence of a life lived with ASD, is unclear.

Association between cholesterol levels and infections after ischemic stroke.

BACKGROUND AND PURPOSE: Multiple studies have suggested an immunomodulatory role of cholesterol. We investigated whether cholesterol levels are associated with the risk of infectious complications (ICs) in acute ischemic stroke patients. METHODS: A single-center prospective cohort was analyzed. Total (TOTc), low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels were measured within 24 h from admission. The outcome of interest was the occurrence of any IC (pneumonia, urinary tract infection, sepsis, other infection) during hospitalization. Predictors of ICs were investigated with multivariable logistic regression. RESULTS: A total of 603 patients were included (median age 78 years, 49.3% males), of whom 134 (22.2%) developed an IC. Subjects with ICs had lower TOTc compared with patients without ICs (median 157 vs. 173 mg/dL; P < 0.001). When TOTc was stratified in quartiles, we observed a linear decrease in the prevalence of ICs with higher TOTc levels (Q1, <144 mg/dL, 32.7%; Q2, 145-168 mg/dL, 24.7%; Q3, 169-197 mg/dL, 17.8%; Q4, >197 mg/dL, 13.3% P < 0.001). The inverse relationship between TOTc and ICs remained significant after adjustment for confounders in logistic regression [odds ratio (OR) for 10 mg/dL increase, 0.92; 95% confidence intervals (CI), 0.87-0.97; P = 0.001]. This association was also confirmed for low-density lipoprotein cholesterol (OR, 0.93; 95% CI, 0.88-0.99; P = 0.013) and high-density lipoprotein cholesterol (OR, 0.85; 95% CI, 0.73-0.98; P = 0.026) and was not mediated by statin treatment. CONCLUSION: Higher cholesterol levels are independently associated with lower risk of ICs in ischemic stroke patients. Further studies are needed to confirm our findings and characterize the biological mechanisms underlying this association.

Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-site Sample of Individuals with Autism Spectrum Disorder.

Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and repetitive behaviours were lower in females than males, alongside comparable levels of social interaction and communication difficulties in females and males. Current ADI-R and ADOS scores showed no sex differences for ASD severity. There were lower socio-communicative symptoms in older compared to younger individuals. This large European ASD sample adds to the literature on sex and age variations of ASD symptomatology.

Unraveling molecular pathways shared by Kabuki and Kabuki-like syndromes.

Kabuki syndrome (KS) is a rare genetic syndrome characterized by a typical facial gestalt, variable degrees of intellectual disability, organ malformations, postnatal growth retardation and skeletal abnormalities. So far, KMT2D or KDM6A mutation has been identified as the main cause of KS, accounting for 56%-75% and 3%-8% of cases, respectively. Patients without mutations in 1 of the 2 causative KS genes are often referred to as affected by Kabuki-like syndrome. Overall, they represent approximately 30% of KS cases, pointing toward substantial genetic heterogeneity for this condition. Here, we review all currently available literature describing KS-like phenotypes (or phenocopies) associated with genetic variants located in loci different from KMT2D and KDM6A . We also report on a new KS phenocopy harboring a 5 Mb de novo deletion in chr10p11.22-11.21. An enrichment analysis aimed at identifying functional Gene Ontology classes shared by the 2 known KS causative genes and by new candidate genes currently associated with KS-like phenotypes primarily converges upon abnormal chromatin remodeling and transcriptional dysregulation as pivotal to the pathophysiology of KS phenotypic hallmarks. The identification of mutations in genes belonging to the same functional pathways of KMT2D and KDM6A can help design molecular screenings targeted to KS-like phenotypes.

Conservative management of primary non-refluxing megaureter during the first year of life: A longitudinal observational study.

INTRODUCTION: There is a lack of prospective studies that include a selected population of patients with primary non-refluxing megaureter (PM). Thus, a longitudinal observational study was designed to follow from birth a selected population of children with PM; all were antenatally diagnosed. In this paper, the outcomes observed in the first year of life are presented. OBJECTIVE: The primary aim was to follow the natural history of PM. The secondary aim was to monitor the onset of any potential complications such as urinary tract infections (UTIs), need for hospitalization and need for surgical correction. STUDY DESIGN: All children with antenatally diagnosed PM, born between January 2007 and December 2013, were prospectively followed with observational management: renal ultrasonography and clinical evaluation on a 3-month basis; urinalysis and culture in case of symptoms; and mercaptoacetyltriglycine (MAG3) nuclear scan once older than 1 month. Children presenting at birth with mild urinary tract dilatation were included in Group A; those with moderate-to-severe dilatation were included in Group B. Continuous antibiotic prophylaxis (CAP) was administered to Group B. RESULTS: Forty-seven children (44 males, three females) with 58 PM were included in the study. The participants and their corresponding outcomes are shown in the summary Table. The presence of obstruction at renogram was a significant predictor of UTIs and hospitalization. DISCUSSION: The strengths of this study were its prospective nature and its very consistent population. A limitation was the lack of control groups. The results regarding the negligible incidence of complications in Group A and the residual incidence of febrile UTIs (20%) and hospitalization (17%) in Group B, even with CAP, are in line with previous literature. In contrast, there was a higher risk of UTIs observed in children aged older than 6 months. CONCLUSIONS: Resolution or improvement is expected in all cases of PM with mild postnatal dilatation, and close to 60% of those with moderate or severe dilatation. Surgery is rarely performed on children younger than 1 year of age. It is safe to observe children with mild urinary tract dilatation without CAP, because the incidence of UTIs is negligible. In those presenting with moderate or severe urinary tract dilatation, despite CAP, a residual incidence of UTIs is seen, and symptomatic patients often require hospitalization. However, UTIs are well tolerated and do not seem to modify outcome. Cases showing obstruction on the MAG3 scan seem to be at higher risk of UTIs and hospitalization.

Migraine genetics: current findings and future lines of research.

In the last two decades, migraine research has greatly advanced our current knowledge of the genetic contributions and the pathophysiology of this common and debilitating disorder. Nonetheless, this knowledge still needs to grow further and to translate into more effective treatments. To date, several genes involved in syndromic and monogenic forms of migraine have been identified, allowing the generation of animal models which have significantly contributed to current knowledge of the mechanisms underlying these rare forms of migraine. Common forms of migraine are instead posing a greater challenge, as they may most often stem from complex interactions between multiple common genetic variants, with environmental triggers. This paper reviews our current understanding of migraine genetics, moving from syndromic and monogenic forms to oligogenic/polygenic migraines most recently addressed with some success through genome-wide association studies. Methodological issues in study design and future perspectives opened by biomarker research will also be briefly addressed.

Anti-brain antibodies are associated with more severe cognitive and behavioral profiles in Italian children with Autism Spectrum Disorder.

Circulating 45 and 62kDa antibodies targeting the cerebellum were previously associated with Autism Spectrum Disorder (ASD), lower adaptive/cognitive function and aberrant behaviors. Moreover, 37, 39 and 73kDa maternal antibodies (mAb) targeting the fetal brain were previously correlated with broad autism spectrum, irritability, abnormal brain enlargement and impaired expressive language. The present study aims towards clinically characterizing individuals with brain-targeted IgG and/or exposed to maternal antibrain antibodies in a large sample of Italian autistic children (N=355), their unaffected siblings (N=142) and mothers (N=333). The presence of patient- and mother-produced anti-brain antibodies does not confer increased risk of autism within the same sibship. However, the 45 and 62kDa antibodies are correlated with autism severity: the 45kDa Ab is associated with cognitive impairment and lower scores at the Vineland Adaptive Behavior Scales, the 62kDa Ab with motor stereotypies, while both correlate with larger head circumference (all P<0.05). On the other hand, maternal 37, 39 and 73kDa antibrain antibodies, either alone or in combination, are correlated with impaired verbal and non-verbal language development, neurodevelopmental delay and sleep/wake cycle disturbances in their autistic children (P<0.05). Presence of the 62kDa autoAb in the child is significantly associated with presence of the 39 and/or 73kDa antibodies in his/her mother. Our results confirm and extend previous observations in an ethnically distinct sample, providing further evidence of a pathomorphic role for anti-brain antibodies in autism while demonstrating their familial clustering.

Ultrasound-guided Hartmann's solution enema: first-choice procedure for reducing idiopathic intussusception.

PURPOSE: This study was undertaken to compare the effectiveness of ultrasound-guided Hartmann's solution enema (US-E) and radiological liquid enema (RX-E) in reducing idiopathic ileocecocolic intussusceptions in relation to patient age and symptom duration. MATERIALS AND METHODS: The study group consisted of 42 patients with idiopathic ileocecocolic intussusception treated with US-E (20 patients) or RX-E (23 patients), with one patient undergoing both procedures owing to recurrence. Patients were divided into subgroups according to age (<6 months, 6-12 months, >12 months) and symptom duration (<12 h, 12-24 h, >24 h). RESULTS: Complete reduction was achieved in 15/20 patients treated with US-E (75%) and in 10/23 treated with RX-E (43.5%) (p=ns). Recurrence was observed in 1/20 US-E and 0/23 RX-E (p=ns) patients. No complications were encountered. US-E had a significantly higher success rate than RX-E in patients >12 months (p=0.0063) and with symptom duration >24 h (p=0.0361). No differences were found in the other subgroups (p=ns). CONCLUSIONS: US-E and RX-E are procedures of comparable value and safety in reducing idiopathic intussusception. US-E seems to be more effective in patients >12 months or with symptom duration >24 h. As US-E avoids radiation exposure, it should be considered the first-choice procedure for reducing idiopathic ileocecocolic intussusception, particularly in these two subgroups of patients.

Case report: Inflammatory myofibroblastic tumor of pancreatic origin in a patient with down syndrome: The role of diagnostic ultrasound.

INTRODUCTION: Inflammatory myofibroblastic tumor (IMT) is a benign solid tumor of uncertain etiology. MATERIALS AND METHODS: We report a case of a 4-year-old Down syndrome affected child, who had a pancreatic mass identified by ultrasonography (US) and confirmed by computed tomography (CT). RESULTS: Monitoring of IMT was performed by serial US studies, and at follow-up after 4 years there was no relapse. DISCUSSION: As radical removal of the lesion was not possible, the patient was successfully treated with nonsteroidal anti-inflammatory drugs (NSAIDs). It was decided to monitor the lesion by serial US in order to reduce the number of CT examinations and thereby avoid excessive exposure to ionizing radiation. It is widely reported in the literature that repeated CT scans are associated with increased exposure to radiation which may cause cancer, a fact which should not be overlooked in children.

Altered calcium homeostasis in autism-spectrum disorders: evidence from biochemical and genetic studies of the mitochondrial aspartate/glutamate carrier AGC1.

Autism is a severe developmental disorder, whose pathogenetic underpinnings are still largely unknown. Temporocortical gray matter from six matched patient-control pairs was used to perform post-mortem biochemical and genetic studies of the mitochondrial aspartate/glutamate carrier (AGC), which participates in the aspartate/malate reduced nicotinamide adenine dinucleotide shuttle and is physiologically activated by calcium (Ca(2+)). AGC transport rates were significantly higher in tissue homogenates from all six patients, including those with no history of seizures and with normal electroencephalograms prior to death. This increase was consistently blunted by the Ca(2+) chelator ethylene glycol tetraacetic acid; neocortical Ca(2+) levels were significantly higher in all six patients; no difference in AGC transport rates was found in isolated mitochondria from patients and controls following removal of the Ca(2+)-containing postmitochondrial supernatant. Expression of AGC1, the predominant AGC isoform in brain, and cytochrome c oxidase activity were both increased in autistic patients, indicating an activation of mitochondrial metabolism. Furthermore, oxidized mitochondrial proteins were markedly increased in four of the six patients. Variants of the AGC1-encoding SLC25A12 gene were neither correlated with AGC activation nor associated with autism-spectrum disorders in 309 simplex and 17 multiplex families, whereas some unaffected siblings may carry a protective gene variant. Therefore, excessive Ca(2+) levels are responsible for boosting AGC activity, mitochondrial metabolism and, to a more variable degree, oxidative stress in autistic brains. AGC and altered Ca(2+) homeostasis play a key interactive role in the cascade of signaling events leading to autism: their modulation could provide new preventive and therapeutic strategies.

Autistic phenotypes and genetic testing: state-of-the-art for the clinical geneticist.

Autism spectrum disorders represent a group of developmental disorders with strong genetic underpinnings. Several cytogenetic abnormalities or de novo mutations able to cause autism have recently been uncovered. In this study, the literature was reviewed to highlight genotype-phenotype correlations between causal gene mutations or cytogenetic abnormalities and behavioural or morphological phenotypes. Based on this information, a set of practical guidelines is proposed to help clinical geneticists pursue targeted genetic testing for patients with autism whose clinical phenotype is suggestive of a specific genetic or genomic aetiology.

Involvement of the PRKCB1 gene in autistic disorder: significant genetic association and reduced neocortical gene expression.

Protein kinase C enzymes play an important role in signal transduction, regulation of gene expression and control of cell division and differentiation. The fsI and betaII isoenzymes result from the alternative splicing of the PKCbeta gene (PRKCB1), previously found to be associated with autism. We performed a family-based association study in 229 simplex and 5 multiplex families, and a postmortem study of PRKCB1 gene expression in temporocortical gray matter (BA41/42) of 11 autistic patients and controls. PRKCB1 gene haplotypes are significantly associated with autism (P<0.05) and have the autistic endophenotype of enhanced oligopeptiduria (P<0.05). Temporocortical PRKCB1 gene expression was reduced on average by 35 and 31% for the PRKCB1-1 and PRKCB1-2 isoforms (P<0.01 and <0.05, respectively) according to qPCR. Protein amounts measured for the PKCbetaII isoform were similarly decreased by 35% (P=0.05). Decreased gene expression characterized patients carrying the 'normal' PRKCB1 alleles, whereas patients homozygous for the autism-associated alleles displayed mRNA levels comparable to those of controls. Whole genome expression analysis unveiled a partial disruption in the coordinated expression of PKCbeta-driven genes, including several cytokines. These results confirm the association between autism and PRKCB1 gene variants, point toward PKCbeta roles in altered epithelial permeability, demonstrate a significant downregulation of brain PRKCB1 gene expression in autism and suggest that it could represent a compensatory adjustment aimed at limiting an ongoing dysreactive immune process. Altogether, these data underscore potential PKCbeta roles in autism pathogenesis and spur interest in the identification and functional characterization of PRKCB1 gene variants conferring autism vulnerability.

Polymorphic GGC repeat differentially regulates human reelin gene expression levels.

The human gene encoding Reelin (RELN), a pivotal protein in neurodevelopment, includes a polymorphic GGC repeat in its 5' untranslated region (UTR). CHO cells transfected with constructs encompassing the RELN 5'UTR with 4-to-13 GGC repeats upstream of the luciferase reporter gene show declining luciferase activity with increasing GGC repeat number (P < 0.005), as predicted by computer-based simulations. Conversely, RELN 5'UTR sequences boost reporter gene expression above control levels in neuronal SN56 and N2A cell lines, but 12- and 13-repeat alleles still yield 50-60% less luciferase activity compared to the more common 8- and 10-repeat alleles (P < 0.0001). RELN "long" GGC alleles significantly blunt gene expression and may, through this effect, confer vulnerability to human disorders, such as schizophrenia and autism.

Paraoxonase gene variants are associated with autism in North America, but not in Italy: possible regional specificity in gene-environment interactions.

Organophosphates (OPs) are routinely used as pesticides in agriculture and as insecticides within the household. Our prior work on Reelin and APOE delineated a gene-environment interactive model of autism pathogenesis, whereby genetically vulnerable individuals prenatally exposed to OPs during critical periods in neurodevelopment could undergo altered neuronal migration, resulting in an autistic syndrome. Since household use of OPs is far greater in the USA than in Italy, this model was predicted to hold validity in North America, but not in Europe. Here, we indirectly test this hypothesis by assessing linkage/association between autism and variants of the paraoxonase gene (PON1) encoding paraoxonase, the enzyme responsible for OP detoxification. Three functional single nucleotide polymorphisms, PON1 C-108T, L55M, and Q192R, were assessed in 177 Italian and 107 Caucasian-American complete trios with primary autistic probands. As predicted, Caucasian-American and not Italian families display a significant association between autism and PON1 variants less active in vitro on the OP diazinon (R192), according to case-control contrasts (Q192R: chi2=6.33, 1 df, P<0.025), transmission/disequilibrium tests (Q192R: TDT chi2=5.26, 1 df, P<0.025), family-based association tests (Q192R and L55M: FBAT Z=2.291 and 2.435 respectively, P<0.025), and haplotype-based association tests (L55/R192: HBAT Z=2.430, P<0.025). These results are consistent with our model and provide further support for the hypothesis that concurrent genetic vulnerability and environmental OP exposure may possibly contribute to autism pathogenesis in a sizable subgroup of North American individuals.

Enhanced APOE2 transmission rates in families with autistic probands.

We have previously described linkage/association between reelin gene polymorphisms and autistic disorder. APOE also participates in the Reelin signaling pathway, by competitively antagonizing Reelin binding to APOE receptor 2 and to very-low-density lipoprotein receptors. The APOE2 protein variant displays the lowest receptor binding affinity compared with APOE3 and APOE4. In this study, we assess linkage/association between primary autism and APOE alleles in 223 complete trios, from 119 simplex Italian families and 44 simplex and 29 multiplex Caucasian-American families. Statistically significant disequilibrium favors the transmission of epsilon2 alleles to autistic offspring, over epsilon3 and epsilon4 (allele-wise transmission/disequilibrium test [TDT], chi2 = 6.16, 2 degrees of freedom [d.f.], P<0.05; genotype-wise TDT, chi2 = 10.68, 3 d.f., P<0.05). A novel epsilon3r allele was also discovered in an autistic child and his mother. Autistic patients do not differ significantly from unaffected siblings (allele-wise TDT comparing autistic patients versus unaffected sibs, chi2 = 1.83, 2 d.f., P<0.40, not significant). The major limitation of this study consists of our small sample size of trios including one unaffected sibling, currently not possessing the statistical power necessary to conclusively discriminate a specific association of epsilon2 with autism, from a distorted segregation pattern characterized by enhanced epsilon2 transmission rates both to affected and unaffected offspring. Our findings are thus compatible with either (a) pathogenetic contributions by epsilon2 alleles to autism spectrum vulnerability, requiring additional environmental and/or genetic factors to yield an autistic syndrome, and/or (b) a protective effect of epsilon2 alleles against the enhanced risk of miscarriage and infertility previously described among parents of autistic children.

Subjective tinnitus, temporomandibular joint dysfunction, and serotonin modulation of neural plasticity: causal or casual triad?

Tinnitus and temporomandibular joint dysfunction (TMJD) are among the most common complaints encountered by physicians. Though the relationship between tinnitus and TMJD has attracted great interest during the past several years, theories attempting to explain this association are still few and inconsistent. Conceivably, TMJD could irritate auricolo-temporal nerve (ATN), triggering a somatosensory pathway-induced disinhibition of dorsal cochlear nucleus (DCN) activity in the auditory pathway. In genetically-predisposed TMJD patients, signals from cronically stimulated DCNs activating specific cortical neuronal networks, could yield plastic neural changes resulting in tinnitus. Based on current evidence of serotoninergic modulation of neural activity and plasticity in sensory pathways, reduced serotoninergic tone could promote plastic changes underlying tinnitus through diminished filtering of incoming signals. Therefore, the early establishment of specific treatments aimed at improving TMJD and/or boosting serotoninergic activity may be required to prevent the creation of 'tinnitus memory circuits'.

Serotonin transporter gene promoter variants do not explain the hyperserotoninemia in autistic children.

Autism is a biologically-heterogeneous disease. Distinct subgroups of autistic patients may be marked by intermediate phenotypes, such as elevated serotonin (5-HT) blood levels, potentially associated with different underlying disease mechanisms. This could lead to inconsistent genetic association results, such as those of prior studies on serotonin transporter (5-HTT) gene promoter variants and autistic disorder. Contributions of 5-HTT gene promoter alleles to 5-HT blood levels were thus investigated in 134 autistic patients and 291 first-degree relatives. Mean 5-HT blood levels are 11% higher in autistic patients carrying the L/L genotype, compared to patients with the S/S or S/L genotype; this trend is not observed in first-degree relatives. The probability of inheriting L or S alleles is significantly enhanced in patients with 5-HT blood levels above or below the mean, respectively (P < 0.05), but quantitative TDT analyses yield a non-significant trend (P = 0.10), as this polymorphism explains only 2.5% of the variance in 5-HT blood levels of autistic patients. In conclusion, 5-HTT gene promoter variants seemingly exert a small effect on 5-HT blood levels in autistic children, which largely does not account for hyperserotoninemia. Nonetheless, the inconsistent outcome of prior association studies could partly stem from a selection bias of hyper- or hypo-serotoninemic probands.

Increased hippocampal DNA oxidation in serotonin transporter deficient mice.

The serotonin transporter (5HTT) is the molecule responsible for the high-affinity reuptake of 5HT from the synaptic cleft. Mice lacking the 5HTT exhibit highly elevated extracellular concentrations of 5HT. We assessed whether the glutathione detoxification system is altered in 5HTT-deficient mice. While levels of reduced and oxidized glutathione were unchanged, glutathione metabolising enzymes showed a differential pattern of modulation. Glutathione peroxidase was reduced in frontal cortex, brainstem, and cerebellum of 5HTT-deficient mice, though not to a statistically significant extent, while a putative isoform of the detoxifying enzyme glutathione-S-transferase pi was decreased in a number of brain regions, especially in brainstem. At the level of the DNA, we found an increase of oxidative DNA adducts in the hippocampus of 5HTT-deficient mice. Given the importance of the hippocampus in learning and memory, this may be the most important neurochemical consequence of the absence of the 5HTT.

No association between the 4g/5G polymorphism of the plasminogen activator inhibitor-1 gene promoter and autistic disorder.

Plasmin, a serine protease, is involved in many physiologically relevant processes, including haemostasis, cellular recruitment during immune response, tumour growth, and also neuronal migration and synaptic remodelling. Both tissue-type and urokinase-type plasminogen activators can be efficiently inhibited by plasminogen activator inhibitor-1 (PAI-1), a protease inhibitor of the serpin family. The human PAI-1 gene is located on chromosome 7q, within or close to a region that has been linked to autism in several linkage studies. Autism seems to be characterized by altered neuronal cytoarchitecture, synaptogenesis and possibly also cellular immune responses. We began addressing the potential involvement of the PAI-1 gene in autistic disorder with this linkage/association study, assessing transmission patterns of the 4G/5G polymorphism in the PAI-1 gene promoter that was previously shown to significantly affect PAI-1 plasma levels. No linkage/association was found in 167 trios with autistic probands, recruited in Italy and in the USA. We thus found no evidence that this polymorphism, or putative functionally relevant gene variants in linkage disequilibrium with it, confer vulnerability to autistic disorder.