Normal intellectual skills in patients with Rhombencephalosynapsis.

OBJECTIVES: Rhombencephalosynapsis (RES) is a very rare cerebellar malformation. Neurodevelopmental outcome of apparently isolated RES remains poorly documented and standardized cognitive assessment, reported in only nine published cases so far, is lacking. Prenatal counselling is challenging considering the uncertain prognosis of isolated RES. The aim of this study was to focus on cognitive and motor outcome of isolated RES with a clinical description of six new cases and a detailed review of the literature. METHODS: A single-centre retrospective study of all RES patients over a 15-year period. Ataxia and fine motor skills were scored using a five-grade scale, according to the degree of disturbance of daily living. Intelligence Quotient (IQ) was established according to age-related Weschler Intelligence Scales. A systematic literature review included published cases with relevant outcome data. RESULTS: Six new cases of apparently isolated RES were reported, including three diagnosed in prenatal settings. The onset age for walking was delayed in four patients. Three patients had head shaking and three had a strabismus. One patient had a mild motor disability, one had subtle ataxia that did not impair daily life and four patients had a normal neurological examination at the last visit. Intellectual abilities were normal in all patients (full IQ score from 90 to 142), although three had ADHD. All received standard schooling. Based on these six new cases, as well as cases from 12 publications in the literature, a total of 28 patients with non-syndromic RES were analysed. Concerning motor outcome, 72% had no complaint or minimal impairment, 16% moderate and 12% severe impairment. Concerning cognitive outcome, 68% had normal cognitive skills, 18% borderline intellectual functioning and 14% moderate to severe disability.

Outcome of isolated agenesis of the corpus callosum: A population-based prospective study.

OBJECTIVES: Neurodevelopmental outcome of apparently isolated agenesis of the corpus callosum (ACC) remains a major concern with uncertain prognosis. Despite "normal" IQ reported in a majority of patients, the rates of learning disabilities and severe outcome (ranging from 0% to 20%) are not clearly established. METHODS: A large population-based series was investigated based on a longitudinal follow-up until school age, using Wechsler Intelligence scales at 3, 5, and 7 years. RESULTS: Fifty women were referred to a tertiary referral unit for an "apparently" isolated ACC confirmed by ultrasound, foetal MRI, and karyotyping or array CGH. Twelve pregnancies were terminated, one foetus died in utero, one pregnancy outcome was unknown, and 36 babies were born. Two were lost to follow-up. Thirty-four children could be classified into three groups. Group 1 comprised two children (6%) with severe intellectual disability (one Mowat-Wilson syndrome and one ASD). Group 2 comprised 10 children (29%) who had learning disabilities and borderline intellectual functioning (VIQ and/or PIQ scores >70 and <85); three patients had hypopituitarism with additional MRI anomalies revealed after birth. Group 3 comprised 22 children (65%) who had both VIQ and PIQ >85 (-1 SD) with a normal school level. Longitudinal follow-up revealed weaker PIQ in younger children which improved with age. CONCLUSION: Our data indicate that intellectual ability is normal (IQ > 85) in approximately two thirds and borderline in just over a quarter of patients. However, a low risk of severe cognitive impairment exists, and this information should be shared with couples during prenatal counselling.