Self‐injurious behavior in young boys with fragile X syndrome

Abstract

In this study, we distributed surveys to 67 families of young boys with fragile X syndrome to determine the prevalence, onset, form, function, location, and correlates of self-injurious behavior. Fifty-five surveys were completed (82%). The mean age of the boys at the time of the survey was 80 months (range = 20-144). Self-injurious behavior (SIB) was reported for 58% of the participants with a mean age of onset of 31 months. The mean number of forms of self-injury was 2 per participant. Biting was the most commonly reported form of self-injury with the fingers and back of the hand disproportionately targeted as the most prevalent self-injury body site. There was no linear increase in risk of SIB with age past 25 months. SIB was reported as most likely to occur following the presentation of difficult task demands or changes in routine. Significant group differences were found between overall ratings of problem behavior for boys with self-injury compared to those without self-injury. Groups did not differ on measures of fragile X mental retardation protein (FMRP), autism status, adaptive behavior, or age first medicated. Results are discussed in terms of future research designed to further elucidate the behavioral phenotype of fragile X syndrome.

Decreased Nociceptive Sensitization in Mice Lacking the Fragile X Mental Retardation Protein: Role of mGluR1/5 and mTOR

“…Finally, a major behavioral feature of fragile X mental retardation is self-injurious behavior (Symons et al, 2003). The connection between self-injurious behavior and pain sensitivity is not fully understood (Symons and Danov, 2005), but there are indications that self-injurious behaviors can be reduced by increasing pain sensitivity with opioid antagonist treatment (Osman and Loschen, 1992;Symons et al, 2004).…”

“…Although deficits in nociceptive sensitization are unlikely to precipitate selfinjurious behavior, this hypothesis does provide a rationale for the persistence of such behavior. We are not aware of clinical studies that address the notion that self-injurious behavior is related to decreased nociceptor sensitization in experimental pain models (and there are obvious ethical concerns in conducting such studies), but it is nonetheless interesting that selfinjurious behavior is a common behavioral feature of many developmental disorders characterized by deficits in synaptic plasticity (Osman and Loschen, 1992;Percy, 2002;Symons et al, 2003), including fragile X mental retardation and Rett syndrome (Moretti et al, 2006). Here, in a mouse model of fragile X mental retardation, we have provided behavioral and electrophysiological evidence for marked decreases in plasticity of the nociceptive system.…”

“…A prominent behavioral feature of fragile X mental retardation is self-injurious behavior (Symons et al, 2003), suggesting alterations in pain processing. We have previously demonstrated that FMRP is expressed by nociceptors and localizes to axons of these pain-sensing neurons as well as to neurons throughout the superficial dorsal horn (Price et al, 2006).…”

Mental retardation

“…Um problema particularmente comum na população com RM é o comportamento auto-agressivo 77 . A expressão do comportamento varia em diferentes distúrbios, como as síndromes do X-frágil, Lesch-Nyhan, Smith-Magenis, Rett e Prader-Willi.…”

“…Os autores concluíram que existem duas formas de comportamento auto-agressivo: uma associada a dor e dirigida para o local de origem da dor, e outra, mais freqüente, não associada a dor e voltada para as mãos e a cabeça. O manejo desse problema pode incluir técnicas de modificação do comportamento e treinamento na comunicação 77 , bem como uma intervenção farmacológica com inibidores seletivos da recaptação da serotonina, trazodona ou buspirona 79 .…”