GHRL and Prader-Willi syndrome: Talebizadeh et al., (2005) looked at the expression of ghrelin and peptide YY and their receptors in post-mortem samples of six brain regions (frontal, temporal and visual cortices, and pons, medulla and hypothalamus) in three PWS patients and six control samples finding qualitatively similar expression in all samples, although a quantitative (and preliminary) analysis of expression levels was only carried out for the 1 y old PWS and control samples suggesting potential quantitative growth hormone receptor difference [71].