The role of genetic factors and pre- and perinatal influences in the etiology of autism spectrum disorders - indications for genetic referral. / Znaczenie czynników genetycznych oraz przed- i okoloporodowych w etiologii zaburzen ze spektrum autyzmu - wskazania do konsultacji genetycznej.

Autism spectrum disorders (ASD) are caused by disruptions in early stages of central nervous system development and are usually diagnosed in first years of life. Despite common features such as impairment of socio-communicative development and stereotypical behaviours, ASD are characterised by heterogeneous course and clinical picture. The most important aetiological factors comprise genetic and environmental influences acting at prenatal, perinatal and neonatal period. The role of rare variants with large effect i.e. copy number variants in genes regulating synapse formation and intrasynaptic connections is emphasised. Common variants with small effect may also be involved, i.e. polymorphisms in genes encoding prosocial peptides system - oxytocin and vasopressin. The environmental factors may include harmful effects acting during pregnancy and labour, however their specificity until now is not confirmed, and in some of them a primary genetic origin cannot be excluded. In several instances, especially with comorbid disorders - intellectual disability, epilepsy and dysmorphias - a detailed molecular diagnostics is warranted, which currently may elucidate the genetic background of disorder in about 20% of cases.

[Autism spectrum disorders - epidemiology, symptoms, comorbidity and diagnosis]. / Zaburzenia ze spektrum autyzmu - epidemiologia, objawy, wspólzachorowalnosc i rozpoznawanie.

In the new classification of American Psychiatric Association - DSM-5 - a category of autistic spectrum disorders (ASD) was introduced, which replaced autistic disorder, Asperger syndrome, childhood disintegrative disorder and pervasive developmental disorder not otherwise specified. ASD are defined by two basic psychopathological dimensions: communication disturbances and stereotyped behaviors, and the diagnosis is complemented with the assessment of language development and intellectual level. In successive epidemiological studies conducted in 21 century the prevalence of ASD has been rising, and currently is estimated at 1% in general population. The lifetime psychiatric comorbidity is observed in majority of patients. The most common coexisting diagnoses comprise disorders ofanxiety-affective spectrum, and in about 1/3 of patients attention deficit/ hyperactivity disorders could be diagnosed. Prodromal symptoms of ASD may emerge before 12 months of life, however reliability of diagnosis at such an early age is poor. Several screening instruments, based on the parental and/or healthcare professional assessments may be helpful in ASD detection. However, structured interviews and observation schedules remain the gold standard of diagnosis.