Etiology of intellectual disability in individuals from special education schools in the south of Brazil

Abstract

Background Intellectual Disability (ID) is characterized by significant limitations that affect intellectual functioning, adaptive behavior, and practical skills which directly interfere with interpersonal relationships and the environment. In Western countries, individuals with ID are overrepresented in the health system, often due to associated comorbidities, and its life-time cost places ID as one of the most expensive conditions of all diagnoses in the International Classification of Diseases. Most of the people affected (75%) live in low-income countries, suffer from malnutrition, lack health care, and do not have access to adequate treatment. The aim of this study was to obtain an estimate of the diagnostic status as well as the prevalence of familial ID among individuals with serious (moderate or severe) ID in a region of the State of Santa Catarina, investigating attendees of special education schools of the Florianópolis Macroregion. Methods This was a cross-sectional study conducted between August 2011 and August 2014, through a semi-structured screening questionnaire for the collection of relevant developmental, clinical, familial and educational data, applied in an interview to guardians of students of special education schools of the macroregion of Florianópolis. Results The participant special schools enrolled close to 1700 students during the study period and the questionnaire was applied to 849 (50.5%). The male to female ratio of the participants was 1.39:1. Clear etiologic explanations were relatively scarce (24%); most diagnoses referring only to the type and the degree of impairment and for the majority (61.4%) the cause was unknown. About half were sporadic cases within their families (considering three generations). For 44.2% at least one other case of an ID-related condition in the extended family was mentioned, with 293 (34.5%) representing potential familial cases. Conclusion Here we describe the epidemiological profile, the available diagnostics, etiology, family history and possible parental consanguinity of participants with ID of special education schools in the South of Brazil. The main results show the need for etiological diagnosis and uncover the relevance of potential hereditary cases in a population where consanguineous unions have a relatively low frequency (0,6%) and highlight the need for public health actions.

Vision characteristics of Special Olympics athletes seen at the United States National Games 2010–2018

“…Our study cohort, similar to other SOI games worldwide, was predominantly male (Gothwal et al 2017;Special Olympics Health 2018;Woodhouse et al 2004). This is understandable given that males experience higher rates of Down syndrome, autism spectrum disorder, and ID disorders with X-linked inheritance, with about one-third of X-linked ID syndromes associated with ocular abnormalities (Couser et al 2017;Oliveira et al 2020). Our study also found females to have a higher likelihood of reporting eye complaints, specifically headache, and of having tropia on distant and near cover tests.…”

“…2017; Oliveira et al . 2020). Our study also found females to have a higher likelihood of reporting eye complaints, specifically headache, and of having tropia on distant and near cover tests.…”

Diagnostic findings and yield of investigations for children with developmental regression

“…Both autism and ID are complex neurodevelopmental conditions with chromosomal, monogenic, and polygenic causes with many proposed risk genes (Yin et al, 2020). Children with developmental regression may have associated genetic, metabolic or environmental causes identified (Oliveira et al, 2020). Approximately 30% of autistic children have co‐occurring ID or global developmental delay (GDD) (Shenouda et al, 2023).…”

Heterogeneity of Cognitive Profiles in Children and Adolescents with Mild Intellectual Disability (MID)

“…ID is an etiologically diverse condition [ 5 , 6 ], and the specific causes are often difficult to identify. Underlying biological, genetic, and neurological factors are most likely to be identified in persons with severe to profound ID, and they are responsible for even up to 75% of such cases [ 7 , 8 ]. Determining the etiology of MID is more difficult as it has a multifactorial origin consisting of a diverse set of factors, not limited solely to biology and genetics [ 2 ].…”