Evaluation of phonological processing skills of young children with neurofibromatosis type 1

Atypical NF1 Microdeletions: Challenges and Opportunities for Genotype/Phenotype Correlations in Patients with Large NF1 Deletions

Patients with neurofibromatosis type 1 (NF1) and type 1 NF1 deletions often exhibit more severe clinical manifestations than patients with intragenic NF1 gene mutations, including facial dysmorphic features, overgrowth, severe global developmental delay, severe autistic symptoms and considerably reduced cognitive abilities, all of which are detectable from a very young age. Type 1 NF1 deletions encompass 1.4 Mb and are associated with the loss of 14 protein-coding genes, including NF1 and SUZ12. Atypical NF1 deletions, which do not encompass all 14 protein-coding genes located within the type 1 NF1 deletion region, have the potential to contribute to the delineation of the genotype/phenotype relationship in patients with NF1 microdeletions. Here, we review all atypical NF1 deletions reported to date as well as the clinical phenotype observed in the patients concerned. We compare these findings with those of a newly identified atypical NF1 deletion of 698 kb which, in addition to the NF1 gene, includes five genes located centromeric to NF1. The atypical NF1 deletion in this patient does not include the SUZ12 gene but does encompass CRLF3. Comparative analysis of such atypical NF1 deletions suggests that SUZ12 hemizygosity is likely to contribute significantly to the reduced cognitive abilities, severe global developmental delay and facial dysmorphisms observed in patients with type 1 NF1 deletions.

Psychosocial and Socioeconomic Factors in Children with Neurofibromatosis Type 1

The aim of this study is to analyze whether children with familial and sporadic neurofibromatosis type 1 (NF1) differ in psychosocial and socioeconomic aspects such as developmental delay as well as in comorbidities. Medical records of 250 children with NF1 at a median age of 10.6 years (range = 2–20 years at time of data collection) were retrospectively reviewed. Specifically, psychosocial and socioeconomic factors from 88 children with a family history for NF1 and 162 sporadic cases were compared. Comparing IQ, familial cases scored significantly lower than sporadic cases (89.8 vs. 96.5; p = 0.015). IQ scores of children with familial and sporadic NF1 differ depending on level of parental education (mean IQ for high education 101.3 [familial] and 102.8 [sporadic] vs. low education 87.5 [familial] and 90.4 [sporadic]; p < 0.001). No significant differences were found regarding the presence of developmental delay, learning disorders, autism spectrum disorder, or attention deficit hyperactivity disease. Children with inherited NF1 had a significantly lower IQ than sporadic cases. Children with familial NF1 more often had parents with a lower level of education, highlighting a possible impact of NF1 through generations. Also, the present study confirmed previous results in literature regarding high frequencies of learning disabilities, autism spectrum disease, and attention deficits in children with NF1.