Torticollis in 15q11.2 Microdeletion Syndrome: a Rare Association in Angelman-like Syndromes

15q11-13 chromosome region contains five breakpoints (BP1-BP5). Chromosomal rearrangements are common in this region. The microdeletion of BP1-BP2 region represents the 15q11.2 microdeletion syndrome associating with variable phenotype. We investigated a ten years old boy with hypotony. His motoric functions, speech and intellectual development were delayed. He suffered from epilepsy and showed dysmorphic features. Some of these dysmorphic features such us epicanthus and the clynodactyly of the fifth fingers can be observed in Angelman or Prader-Willi syndromes but have not been described in the 15q11.2 microdeletion syndrome so far. He has congenital torticollis that has been described earlier neither in this microdeletion syndrome nor in Prader-Willi Angelman syndromes. Our aim is to find the possible mechanisms leading to the phenotype using Metilation Specific Multi Ligand Probe Assay, Polimerase Chain Reaction and Array Comparative Genomic Hybridization. The 15q11.2 microdeletion syndrome represents an example for the incomplete penetrance and variable expressivity. Further genetic changes, such as other defective genes, further copy number variations, variability in non-coding regions, the mRNA quantity, environmental effects and epigenetic modification may also influence on the severity of the symptoms. We suggest to classify the symptoms into two groups (major and minor criteria). Depending on the existing minor criteria, this syndrome could be identified as Angelman-like or Prader-Willi-like syndromes.