Novel mutations in the CDKL5 gene, predicted effects and associated phenotypes

It has been found that CDKL5 gene mutations are responsible for early-onset epilepsy and drug resistance. We screened a population of 92 patients with classic/atypical Rett syndrome, 17 Angelman/Angelman-like patients and six idiopathic autistic patients for CDKL5 mutations and exon deletions and identified seven novel mutations: six in the Rett subset and one in an Angelman patient. This last, an insertion in exon 11, c.903_904 dupGA, p.Leu302Aspfx49X, is associated with a relatively mild clinical presentation as the patient is the only one capable of sitting and walking alone. Of the six mutations, two are de novo missense changes affecting highly conserved aminoacid residues, c.215 T > C p.Ile72Thr and c.380A > G p.His127Arg (present in a mosaic condition) found in two girls with the most severe clinical presentation, while the remaining are the splicing c.145 + 2 T > C and c.2376 + 5G > A, the c.1648C > T p.Arg550X and the MPLA-identified c.162_99del261 mutation. RNA characterisation of four mutations revealed the aberrant transcript of the missense allele (case 2) and not the stop mutation (case 3), but also allowed the splicing mutation (case 1) and the c.-162_99del261 (case 4) to be categorised as truncating. The obtained data reinforce the view that a more severe phenotype is due more to an altered protein than haploinsufficiency. Furthermore, the mutational repertoire of the CDKL5 gene is shown to be expanded by testing patients with phenotypical overlap to Rett syndrome and applying multiplex ligation-dependent probe amplification.

Unilateral frontal lobe epilepsy affects executive functions in children

Very few studies to date have investigated the neuropsychological changes detectable in children suffering from frontal lobe epilepsy (FLE). The aim of the present study was to assess the effects of FLE on cognitive and executive functions in childhood. The sample includes 17 children with a frontal epileptogenic focus (10 right and 7 left), with no evidence of anatomical brain damage. These subjects were assessed by means of a battery of tests to investigate executive functioning. The results emphasised the presence of selective impairments of frontal lobe functions without evidence of deficits in global intellectual functioning. No side-specific deficits were detected, while an earlier onset of epilepsy and the duration of the disorder, but not the seizures frequency, were found to correspond with more severe deficits in some specific frontal lobe functions.

Intrathecal methotrexate affects cognitive function in children with medulloblastoma

BACKGROUND

Cognitive impairment occurs after malignant brain tumor treatment in children, following brain radiotherapy and systemic and intrathecal chemotherapy.

OBJECTIVES

1) To compare two groups of children who underwent surgery for cerebellar medulloblastoma with their cousins and siblings, assessing intelligence, executive function, attention, visual perception, and short-term memory. Both groups were treated with the same combined radiotherapy-chemotherapy, but differed in that only one group received intrathecal methotrexate (MTX+). 2) To relate these measures to MRI findings (leukomalacia).

RESULTS

The two groups performed worse than their control subjects in all tests. The MTX+ group younger than 10 years performed significantly worse in all tests, particularly executive ones. The group older than 10 years performed significantly worse only in short-term memory. Younger patients without MTX performed significantly worse than controls only in some neuropsychological measures; there were no differences between older patients and control subjects. Only in the MTX+ group was there a direct correlation between extent of leukomalacia and performance in some tests.

CONCLUSIONS

The administration of intrathecal methotrexate to children with medulloblastoma worsens the cognitive deficits induced by chemotherapy and radiotherapy. The use of intrathecal methotrexate in the treatment of medulloblastoma and other malignancies should be reassessed.

Late neuropsychological and behavioural outcome of children surgically treated for craniopharyngioma

Late outcome in 12 children treated by radical surgery for craniopharyngioma is presented. None of the patients presented underwent fractionated traditional or stereotactic radiotherapy. The results show no neurological (except visual dysfunction in 6 subjects), cognitive or short-term memory deficits. Three children were found to have a minor attention deficit. In 5 cases "frontal lobe" malfunctioning was disclosed, and in 5 there were bursts of unpredictable anger. Three children showed worsening of functioning at school: a combination of various causes is suggested to explain the worsening of academic performances. The size of the sample calls for a careful evaluation of results, with due consideration for the influence of various factors on outcome. Multicentre studies are required to increase the sample size and achieve more general conclusions.

MRI features of cerebral lesions and cognitive functions in preterm spastic diplegic children

The aim of this study is to further clarify the relation between the pattern of cognitive impairment in spastic diplegic children born preterm and MRI features of cerebral lesions. The cognitive profile by Wechsler Scale of a sample of 30 children aged 6 years, 8 months to 14 years, 7 months was assessed, and the correlations between the Full Scale, Verbal, and Performance IQ and periventricular leukomalacia features on MRI were investigated. A significant difference was observed between the mean Verbal and Performance IQ, indicating a specific failure in the visuoperceptual functions of spastic diplegic children born preterm. Periventricular leukomalacia was detected in all children. The severity of ventricular dilatation, the degree and extent of white matter reduction, optic radiation involvement, and the thinning of the posterior corpus callosum correlated significantly with the Full Scale and Performance IQ: no correlation was observed between the Verbal IQ and any of the MRI features analyzed. In spastic diplegic children, an MRI examination between the ages of 1 and 2 years may be helpful in predicting a specific neuropsychological pattern of dysfunction and in defining an early intervention program.