Cognitive impairments are different in single-incidence and multi-incidence ADHD families.

Background: We may improve our understanding of the role of common versus unique risk factors in attention-deficit/hyperactivity disorder (ADHD) by examining ADHD-related cognitive deficits in single- (SPX), and multi-incidence (MPX) families. Given that individuals from multiplex (MPX) families are likely to share genetic vulnerability for the disorder, whereas simplex (SPX) ADHD may be the result of sporadic (non-)genetic causes unique to the patient, we hypothesized that cognitive impairments may be different in SPX and MPX ADHD as indicated by (a) the presence of cognitive deficits in MPX, but not SPX unaffected siblings and (b) dissimilar cognitive profiles in SPX and MPX ADHD patients.

Methods: Tasks measuring total IQ, verbal attention, executive functioning, motor functioning, and time estimation were administered to 31 SPX/264 MPX ADHD probands, 47 SPX/123 MPX unaffected siblings, and 263 controls, aged 6-19 years.

Simplex and multiplex stratification in ASD and ADHD families: a promising approach for identifying overlapping and unique underpinnings of ASD and ADHD?

Autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD) are highly heterogeneous neuropsychiatric disorders, that frequently co-occur. This study examined whether stratification into single-incidence (SPX) and multi-incidence (MPX) is helpful in (a) parsing heterogeneity and (b) detecting overlapping and unique underpinnings of the disorders. ASD and ADHD traits were measured in 56 ASD/31 ADHD SPX families, 59 ASD/171 ADHD MPX families and 203 control families.

Testing the extreme male brain theory of autism spectrum disorder in a familial design.

Autism Spectrum Disorder (ASD) may be an extreme manifestation of some male-typical traits in both neuroanatomy and cognition. Using the ratio of the second to fourth digit (2D:4D) and digit length as biomarkers of (pre- and postnatal) testosterone levels, examined was whether hypermasculinized digit ratios and/or lengths were familial traits in ASD and investigated their relation to sexually dimorphic cognitive abilities. 2D:4D ratios and digit lengths of 216 children with ASD, 202 unaffected siblings, and 360 parents were compared with those of 174 control children and their 146 parents.

Recognition of facial emotion and affective prosody in children with ASD (+ADHD) and their unaffected siblings.

Autism is a highly heritable and clinically heterogeneous neuropsychiatric disorder that frequently co-occurs with other psychopathologies, such as attention-deficit/hyperactivity disorder (ADHD). An approach to parse heterogeneity is by forming more homogeneous subgroups of autism spectrum disorder (ASD) patients based on their underlying, heritable cognitive vulnerabilities (endophenotypes). Emotion recognition is a likely endophenotypic candidate for ASD and possibly for ADHD.