Joubert syndrome-related disorders (JSRD) are a group of syndromes sharing the neuroradiological features of cerebellar vermis hypoplasia and a peculiar brainstem malformation known as the 'molar tooth sign'. We identified mutations in the CEP290 gene in five families with variable neurological, retinal and renal manifestations. CEP290 expression was detected mostly in proliferating cerebellar granule neuron populations and showed centrosome and ciliary localization, linking JSRDs to other human ciliopathies.

Cerebral visual impairment is a visual function deficit caused by damage to the retrogeniculate visual pathways in the absence of any major ocular disease. It is the main visual deficit in children in the developed world. Preperinatal hypoxic-ischemic damage is the most frequent cause of cerebral visual impairment, but the etiology is variable. The authors set out to evaluate the presence of visual disorders not attributable to any major ocular pathology in a sample of children with central nervous system disease and to describe the clinical picture of cerebral visual impairment in this cohort. One hundred twenty-one patients with central nervous system damage and visual impairment underwent a protocol developed at the authors' center that included neurologic, neurophthalmologic, and neuroradiologic assessments (brain magnetic resonance imaging). Reduced visual acuity was found in 105 of 121 patients, reduced contrast sensitivity in 58, abnormal optokinetic nystagmus in 88, and visual field deficit in 7. Fixation was altered in 58 patients, smooth pursuit in 95, and saccadic movements in 41. Strabismus was present in 88 patients, and abnormal ocular movements were found in 43 patients. Of the 27 patients in whom they could be assessed, visual-perceptual abilities were found to be impaired in 24. Fundus oculi abnormalities and refractive errors were frequently associated findings. This study confirms that the clinical expression of cerebral visual impairment can be variable and that, in addition to already well-documented symptoms (such as reduced visual acuity, visual field deficits, reduced contrast sensitivity), the clinical picture can also be characterized by oculomotor or visual-cognitive disorders. Cerebral visual impairment is often associated with ophthalmologic abnormalities, and these should be carefully sought. Early and careful assessment, taking into account both the neurophthalmologic and the ophthalmologic aspects, is essential for a correct diagnosis and the development of personalized rehabilitation programs.

Aim  Cognitive visual dysfunctions (CVDs) reflect an impairment of the capacity to process visual information. The question of whether CVDs might be classifiable according to the nature and distribution of the underlying brain damage is an intriguing one in child neuropsychology. Method  We studied 22 children born preterm (12 males, 10 females; mean age at examination 8y, range 6–15y; mean gestational age 30wks, range 28–36wks) with periventricular leukomalacia, spastic diplegia, normal intelligence (mean Full‐scale IQ 84; mean Verbal IQ 97; mean Performance IQ 74), and normal visual acuity, focusing on higher visual functions. Brain magnetic resonance images (MRI) were analysed to establish the presence of lesions along the primary optic pathway, in the occipitoparietal and occipitotemporal regions. Results  Most children displayed an uneven cognitive profile, with deficits in visual object recognition, visual imagery, visual–spatial skills, and visual memory, and sparing of visual associative abilities, non‐verbal intelligence, and face and letter recognition. Conventional brain MRI did not document major alterations of parietal and temporal white matter, or cortical alteration of areas involved in visual associative functions. Interpretation  We suggest a widespread involvement of higher visual processing systems, involving both the ventral and dorsal streams, in preterm children with periventricular leukomalacia. The lack of major alterations on conventional MRI does not exclude the possibility of malfunctioning of higher visual processing systems, expressing itself through discrete CVDs. Possible mechanisms underlying these neuropsychological deficits are discussed.

No abstract