Late diagnosis in severe and mild intellectual disability in adulthood

Prenatal Maternal Bereavement and Its Association With Intellectual Disability in the Offspring

OBJECTIVE

This study aimed to examine the association of a mother's loss of a close relative before or during pregnancy with intellectual disability (ID) in the offspring.

METHODS

We performed a nationwide population-based cohort study based on Danish national registries. All live-born singletons born in Denmark during the 1978-2016 period (n = 2,216,601) were followed up starting from birth to 38 years of age. Log-linear Poisson regression was used to estimate the association between maternal bereavement (the death of an older child, a partner, or a parent 1 year before or during pregnancy) and the risk of ID in the offspring.

RESULTS

Maternal bereavement during or before pregnancy was associated with an increased risk of ID (incidence rate ratio [IRR] = 1.15; 95% confidence interval [CI] = 1.04-1.28). The risk of ID was increased by 27% when maternal bereavement occurred during pregnancy (IRR = 1.27; 95% CI = 1.08-1.49). When stratifying on the child's sex, we also observed an increased risk of ID associated with maternal bereavement during pregnancy both for male (IRR = 1.25; 95% CI = 1.02-1.53) and for female (IRR = 1.31; 95% CI = 1.02-1.69), respectively. The IRRs for unnatural death of a relative were also elevated (IRR = 1.22; 95% CI = 0.91-1.64) in general, although the difference was not statistically significant.

CONCLUSIONS

Our findings suggest that prenatal stress due to maternal loss of a close relative may increase the risk of offspring's ID of both sexes, in particular when the loss happened during pregnancy.

Duplication of the Miller-Dieker Critical Region in a Patient with a Subtelomeric Unbalanced Translocation t(10;17)(p15.3;p13.3)

Submicroscopic duplications in the Miller-Dieker critical region have been recently described as new genomic disorders. To date, only a few cases have been reported with overlapping 17p13.3 duplications in this region. Also, small deletions that affect chromosome region 10p14→pter are rarely described in the literature. In this study, we describe, to our knowledge for the first time, a 5-year-old female patient with intellectual disability who has an unbalanced 10;17 translocation inherited from the father. The girl was diagnosed by subtelomeric FISH and array-CGH, showing a 4.43-Mb heterozygous deletion on chromosome 10p that involved 14 genes and a 3.22-Mb single-copy gain on chromosome 17p, which includes the critical region of the Miller-Dieker syndrome and 61 genes. The patient's karyotype was established as 46,XX.arr 10p15.3p15.1(138,206-4,574,436)x1,17p13.3(87,009-3,312,600)x3. Because our patient exhibits a combination of 2 imbalances, she has phenotypic features of both chromosome abnormalities, which have been reported separately. Interestingly, the majority of patients who carry the deletion 10p have visual and auditory deficiencies that are attributed to loss of the GATA3 gene. However, our patient also presents severe hearing and visual problems even though GATA3 is present, suggesting the involvement of different genes that affect the development of the visual and auditory systems.

Caregiver and adult patient perspectives on the importance of a diagnosis of 22q11.2 deletion syndrome

BACKGROUND

Recent advances in genetics are particularly relevant in the field of intellectual disability (ID), where sub-microscopic deletions or duplications of genetic material are increasingly implicated as known or suspected causal factors. Data-driven reports on the impact of providing an aetiological explanation in ID are needed to help justify widespread use of new and expensive genetic technologies.

METHODS

We conducted a survey of caregivers on the value of a genetic/aetiologic diagnosis of 22q11.2 deletion syndrome (22q11.2DS), the most common microdeletion syndrome in ID. We also surveyed the opinion of a high-functioning subset of adults with 22q11.2DS themselves. We used standard quantitative and qualitative methods to analyse the responses.

RESULTS

In total, 73 of 118 surveys were returned (61.9%). There was convergence of quantitative and qualitative results, and consistency between adult patient and caregiver responses. A definitive molecular diagnosis of 22q11.2DS was a critical event with diverse positive repercussions, even if occurring later in life. Frequently cited benefits included greater understanding and certainty, newfound sense of purpose and a platform for advocacy, and increased opportunities to optimise medical, social and educational needs.

CONCLUSIONS

This is the first study to characterise the impact of a diagnosis of this representative microdeletion syndrome on adult patients and their families. The results both validate and expand on the theoretical benefits proposed by clinicians and researchers. The use of genome-wide microarray technologies will provide an increasing number of molecular diagnoses. The importance of a diagnosis of 22q11.2DS demonstrated here therefore has implications for changing attitudes about molecular genetic diagnosis that could benefit individuals with ID of currently unknown cause and their families.

Different, difficult or distinct? Mothers' and fathers' perceptions of temperament in children with and without intellectual disabilities

BACKGROUND

Can ratings of temperament be a way of identifying young children with intellectual disabilities (ID) who are at risk for being experienced as difficult? We aimed to explore parents' reports of temperament in their young children with or without ID, as well as positive and negative impact of the child on parents.

METHOD

Mothers and fathers of 55 children recently diagnosed with ID and 183 age-matched typically developing (TD) children completed the EASI Temperamental Survey and two scales of the Family Impact Questionnaire measuring positive and negative impact of the child on parents.

RESULTS

Parents rated children with mixed ID/DD (developmental delay) as shyer and more impulsive, and less active and sociable when compared with TD children. Children with mixed ID/DD were also reported to have more negative and less positive impact on the family compared with the TD group. In subgroup analyses, children with Down syndrome and cerebral palsy/motor impairment were described as having less negative impact on parents and were described as low in negative emotionality. Children with autism spectrum disorder (ASD), ID/DD nos and other less common diagnoses had a similar pattern of temperament with high emotionality, shyness and impulsivity, and low activity and sociability. Parents of children with ASD and ID/DD reported the highest level of negative impact.

CONCLUSIONS

Temperamental characteristics such as high negative emotionality and impulsivity, which can be identified earlier than behavioural problems, could be indicators of negative impact on parents of young children with ID. Despite great variability in temperament among children with mixed ID/DD, results indicated common temperamental characteristics among children with ASD, ID/DD and other diagnosis.