Behavioral and temperamental features of children with Costello syndrome.

Costello syndrome (CS) is a rare genetic condition due to germline mutations in HRAS proto-oncogene and characterized by increased birth weight, postnatal growth retardation, distinctive facial appearance, typical medical problems (including feeding problems in the neonatal period), cutaneous anomalies, and developmental delay. Outgoing personality has often been noted in case reports, but few studies have focused specifically on the behavioral aspects of CS. A preliminary survey described irritability in younger patients with improvement between age 2 and 4, but a standardized psychometric tool was not used. A second study using the Child Behavior Checklist (CBCL) showed relatively high (albeit subclinical) levels of internalizing problems. These descriptive investigations lacked a control group. We describe a comparative survey to evaluate the behavioral and temperamental features of children with CS. We conducted a cross-sectional assessment using the CBCL and the Emotionality, Activity, Shyness, Sociability (EAS) temperament questionnaire to evaluate behavior and temperament in 11 CS children (2 years 5 months to 9 years) comparing them to 33 gender- and age-matched children without disability. The results suggest that the high levels of internalizing problems found before age 4 in CS patients might decrease with age. They also point to possible "hyperemotionality." Further studies using a larger sample size and IQ-matched control groups are needed to more accurately characterize individuals with this rare syndrome.