Genotypic and phenotypic relationship between Prader-Willi and Prader-Willi-Like syndromes
Prader-Willi-Like syndrome (PWLS) is a rare genetic disorder with clinical features that include hypotonia, obesity, short extremities, and developmental delay. As its name suggests, the clinical phenotypes of PWLS overlap with the genetic imprinting disorder of Prader-Willi Syndrome (PWS). The sharing of phenotypes between these syndromes likely indicates that the genomic regions affected in PWLS are involved in the same genetic pathways associated with developing the PWS phenotype. Thus, the genetic heterogeneity of PWLS and the absence of a molecular diagnosis associated with PWS constitute a clinical challenge for health professionals. This review presents phenotypic and genotypic characteristics related to PWLS described in 34 articles, totaling 74 patients, including alterations involving deletion of 1p, 2p, 6q, 15p, duplication of 15q, Xq, Temple Syndrome, Schaaf-Yang Syndrome, Fragile X syndrome, and even associated mutations. Among the most frequent characteristics related to PWLS are global developmental delay (78%), obesity (68%), hypotonia (51%), speech-articulation problems (42%), and behavioral disorders (41%). This review provides an overview of current knowledge of the genetics and phenotypes associated with PWS and PWLS.