17p13.3 Microduplication Syndrome: Further Delineating The Clinical Spectrum

17p13.3 microduplication syndrome has been associated with a clinical spectrum of phenotypes, and depending on the genes involved in the microduplication, it is categorized into two classes (Class I and Class II). We herein, describe two patients diagnosed with Class I 17p13.3 microduplication by BACs-on-Beads (BoBs) assay and further confirmed by fluorescence in situ hybridization (FISH). Our patients (Patient 1: 4-year-old male; Patient 2: 2-year-old male) presented with developmental delay, intellectual disability, and dysmorphic facial features. When compared with the literature, our patients manifested distinctive features (Patient 1: primary hypothyroidism; Patient 2: bilateral cryptorchidism) that were not previously described in the duplication 17p13.3 spectrum.