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Summary An increased incidence of pertussis has been observed recently in adults, and healthcare workers (HCWs) are considered a risk group for transmission to infants. Prevalence of recent pertussis infection was assessed in HCWs from a paediatric department of a tertiary care hospital in Brazil. Serum pertussis toxin IgG antibodies were measured by enzyme-linked immunosorbent assay. Of 388 HCWs included in the analysis, 6.4% had serology suggestive of recent infection. Medical residents [odds ratio (OR): 4.15; 95% confidence interval (CI): 1.42–12.14; P = 0.009] and those working >40h a week (OR: 3.29; 95% CI: 1.17–9.26; P = 0.024) had increased risk of pertussis infection.

A previous report noted a 27% prevalence of autism in Joubert syndrome (JS), raising the question of overlapping etiologies. Family studies have shown that autism is characterized by family loading for a number of specific behavioral and psychiatric disorders and that the sib recurrence risk is around 4%. The purpose of this study is to determine whether children with Joubert and their families show behavioral or genetic characteristics similar to autism. Thirty-one volunteer Joubert families were identified. Parents completed a semi-structured family history interview and the Autism Behavioral Checklist. Rates of family loading for neuropsychiatric disorders in the JS families were compared to autism family history data and Down syndrome (DS) controls. The JS families had significantly lower rates of autism, alcoholism, cognitive, and language disorders than the autism families. Their rate of depression was lower, but not significantly different from that found in autism families. None of the JS children met the clinical cut-off for autism based on parental symptom report and the sib recurrence risk was 32% for the JS families compared to 4% for the autism and 0% for DS families. These data indicate that JS is a genetically distinct disorder from autism. Different genes with different inheritance patterns that affect neurodevelopment of the cerebellum could explain the clinical similarities previously reported in JS and autism.

Occipitofrontal circumference (OFC) is one of the few physical findings in autism that varies significantly from the norm and is distinct and measurable. As part of a study of genetic heterogeneity of autism, we scrutinized data from a large sample of patients with idiopathic autism (N = 137), using OFC as the categorizing variable. The OFC standard deviation (OFCSD) values of the autistic propositi (0.61+/-1.6) varied significantly from that of the normal population (0.0+/-1.0), (P 2.0, N = 32) with the normocephalic individuals (-2 SD < OFCSD < +2 SD, N = 95) showed no significant differences in sex ratio, morphological status, IQ, seizure prevalence, or recurrence risks. The macrocephalic individuals were slightly less apt than those with normocephaly to have a family history of Attention Deficit Hyperactivity Disorder (ADHD) (P

Heterogeneity within the autism diagnosis obscures the genetic basis of the disorder and impedes our ability to develop effective treatments. We found that by using two readily available tests, autism can be divided into two subgroups, "essential autism" and "complex autism," with different outcomes and recurrence risks. Complex autism consists of individuals in whom there is evidence of some abnormality of early morphogenesis, manifested by either significant dysmorphology or microcephaly. The remainder have "essential autism." From 1995 to 2001, 260 individuals who met DSM-IV criteria for autistic disorder were examined. Five percent (13/260) were microcephalic and 16% (41/260) had significant physical anomalies. Individually, each trait predicted a poorer outcome. Together they define the "complex autism" subgroup, comprising 20% (46/233) of the total autism population. Individuals with complex autism have lower IQs (P=0.006), more seizures (P=0.0008), more abnormal EEGs (46% vs. 30%), more brain abnormalities by MRI (28% vs. 13%). Everyone with an identifiable syndrome was in the complex group. Essential autism defines the more heritable group with higher sib recurrence (4% vs. 0%), more relatives with autism (20% vs. 9%), and higher male to female ratio (6.5:1 vs. 3.2:1). Their outcome was better with higher IQs (P=0.02) and fewer seizures (P=0.0008). They were more apt to develop autism with a regressive onset (43% vs. 23%, P=0.02). Analysis of the features predictive of poor outcome (IQ