A comparison of two studies and the prevalence and sex ratio of Neurodevelopmental conditions in Tuberous Sclerosis Complex

While it is important to determine global prevalence rates to understand the impact of geographic, cultural/ethnic and socioeconomic factors, inequalities in the clinical identification and diagnosis of TAND is well recognised because of marked differences in the nature of health care systems and diagnostic practices between countries (including utilisation of different diagnostic nosological systems which have evolved over time).' (3) Operational criteria for assigning a diagnosis of ASD and ADHD are not provided in the TAND Checklist, and inter-rater reliability for assigning diagnoses has not been reported in the TOSCA study. [...]the patients attended a wide range of different types of clinics (genetic, paediatric, epilepsy, etc.,) that were led by specialists from many different disciplines with variable levels of expertise in clinically recognising and diagnosing TAND. [...]different thresholds for diagnosis of ASD and ADHD traits make it challenging to determine true prevalence; 4. By contrast, complex psychopathologies such as ASD and ADHD where diagnostic tools and operational criteria are increasingly recognised as necessary aids to clinical diagnosis, show quite significant differences in prevalence estimates between studies. [...]the findings from the TS 2000 study regarding the prevalence of definite and probable ASD and ADHD demonstrate how sensitive estimates are to variations in where the threshold for diagnosis is placed, when dealing with dimensionally distributed traits.