Fig. (1). A, B, & C Prader-Willi Phenotype.

A 9 year, 8-month-old full mutation fragile X boy with the Prader-Willi phenotype. He was referred to the Medical Genetics Clinic where Prader-Willi syndrome was ruled out through methylation testing. A karyotype showed a normal male, 46, XY. Fragile X testing was done and came back abnormal with mosaicism for a full mutation and a low level 105 repeat premutation. Notice the round face and prominent ears (Fig. 1A), short fingers (Fig. 1B), and truncal obesity (Fig. 1C).