Clinical case rounds in child and adolescent psychiatry: neurofibromatosis type 1, cognitive impairment, and attention deficit hyperactivity disorder.

Neurofibromatosis Type 1 (NF-1) is an autosomal dominant disorder that occurs in approximately 1 out of every 3000 live bir ths. Common physical features include cafe au lait spots, skinfold freckling, iris hamartomas, and the growth of benign and malignant tumors (Gutmann, 2002). The gene associated with NF-1 has been mapped to the long arm of chromosome 17 and is usually classified as a tumor suppressor gene, explaining the high frequency of benign and malignant tumours found in this disorder (North et al., 2002). In addition to the physical manifestations of NF-1, cognitive impairment is also common (North et al., 2002). Early reports overestimated the degree and prevalence of this impairment or suggested a nonverbal learning disability profile. More rigorous studies conducted over the last 20 years suggest only a slightly increased incidence of mental retardation, intellectual abilities that are generally in the low average range but remain within one standard deviation of the normal population, and an equivalent prevalence of language and nonverbal based deficits (North et al., 1997). An increased incidence of learning disabilities is also reported, with frequencies reported to range between 30 and 65% (North et al., 1997). While a large body of literature has explored the link between intellectual/learning difficulties and NF-1, the relationship between NF-1 and attention deficit hyperactivity disorder (ADHD) has only became a focus of investigation in the last decade. The following two cases, recently assessed in our clinic, are presented to illustrate the attentional and learning concerns associated with NF-1.