Developmental malformation of the corpus callosum: a review of typical callosal development and examples of developmental disorders with callosal involvement

Abstract

This review provides an overview of the involvement of the corpus callosum (CC) in a variety of developmental disorders that are currently defined exclusively by genetics, developmental insult, and/or behavior. I begin with a general review of CC development, connectivity, and function, followed by discussion of the research methods typically utilized to study the callosum. The bulk of the review concentrates on specific developmental disorders, beginning with agenesis of the corpus callosum (AgCC)—the only condition diagnosed exclusively by callosal anatomy. This is followed by a review of several genetic disorders that commonly result in social impairments and/or psychopathology similar to AgCC (neurofibromatosis-1, Turner syndrome, 22q11.2 deletion syndrome, Williams yndrome, and fragile X) and two forms of prenatal injury (premature birth, fetal alcohol syndrome) known to impact callosal development. Finally, I examine callosal involvement in several common developmental disorders defined exclusively by behavioral patterns (developmental language delay, dyslexia, attention-deficit hyperactive disorder, autism spectrum disorders, and Tourette syndrome).

Increased corpus callosum volume in children with chromosome 22q11.2 deletion syndrome is associated with neurocognitive deficits and genetic polymorphisms

“…45 In children with autism, a reduction in volumes of the CC has been reported, with a lack of the age-related positive correlation between age and CC volume. 18 Thus, our findings of the CC volumes are unlikely to be due to a non-specific finding associated with cognitive impairments.…”

“…17 The fiber connections between corresponding hemispheric regions are topographically arranged; thus, structural changes in the CC are reflective of changes in the corresponding cortical areas. Diminished connectivity in the CC may be involved in the pathophysiology of many neurodevelopmental disorders 18 and schizophrenia. 19 We previously reported that the CC area was larger in children with 22q11DS, compared with typically developing children, 20 replicated by others.…”

Predicting Developmental Dyslexia: A Brief Review of Genetics, Language and the Brain

“…The midbody of the corpus callosum is implicated in processing primary sensory and higher order auditory information along with premotor and primary motor cortices [54][55][56]. Large axons within the midbody of the corpus callosum facilitate rapid sensory integration essential to perceive temporal cues in auditory and visual stimuli which are needed for phonological processing and ultimately fluent reading.…”

“…In typical development, the splenium consists of small densely packed axons; thus, splenium enlargement suggests a greater number of axons and greater interhemispheric connectivity [56]. Furthermore, compared to typically developing adults (N=18), individuals with DD (N=9) display increased FA and AD in the splenium [49].…”

Agenesis of the Corpus Callosum Associated with Persistent Primitive Olfactory Artery - Case Report and Literature Review

“…This condition occurs in 1:4000 individuals, which makes it one of the most common human brain malformations [7]. The etiology of ACC has an identifiable cause in about 25% of cases [7], and is usually related to other neurological conditions such as hydrocephalus [8], microcephaly [9], or fetal alcohol syndrome [10].…”