SNARE involved in vesicular transport from the late endosomes to the trans-Golgi network. Genetic variations in STX16 may be a cause of pseudohypoparathyroidism type 1B (PHP1B). Pseudohypoparathyroidism refers to a heterogeneous group of disorders characterized by resistance to parathyroid hormone (PTH). PHP1B is characterized by PTH-resistant hypocalcemia and hyperphosphatemia. Patients affected with PHP1B lack developmental defects characteristic of Albright hereditary osteodystrophy, and typically show no other endocrine abnormalities besides resistance to PTH. In some cases microdeletions involving STX16 appear to cause loss of methylation at exon A/B of the GNAS gene, resulting in PHP1B. Belongs to the syntaxin family. 5 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.