Yeo et al. (2004) reported a boy with early-onset obesity, hyperphagia, and severe developmental delay. Although the patient had a normal birth weight, he rapidly gained weight from age 6 months, and his body mass index (BMI) was ... Yeo et al. (2004) reported a boy with early-onset obesity, hyperphagia, and severe developmental delay. Although the patient had a normal birth weight, he rapidly gained weight from age 6 months, and his body mass index (BMI) was 3.5 SD above normal by age 8 years. Fasting plasma insulin was not markedly elevated and thyroid function tests were normal. There were no dysmorphic features. He demonstrated hyperphagia similar to individuals with congenital leptin deficiency (see 164160). He also had severe developmental delay in motor function, speech, and language, and demonstrated a blunted response to nociceptive stimuli. Yeo et al. (2004) noted the phenotypic similarities between their patient and the mouse model of TrkB deficiency reported by Xu et al. (2003).
In the boy they reported with early-onset obesity, hyperphagia, and severe developmental delay, Yeo et al. (2004) identified a heterozygous de novo mutation in the TRKB gene (600456.0001).