A case report of Williams syndrome with main clinical manifestation of hypercalcemia and gastrointestinal bleeding as the main clinical manifestations, and with an accompanying literature review.

BACKGROUND: Williams syndrome is an autosomal dominant multisystem disorder caused by a 1.5-1.8 Mb deletion on chromosome 7q11.23. It is characterized by facial deformations, cardiovascular abnormalities, developmental delays, gastrointestinal manifestations, and endocrine disorders. CASE DESCRIPTION: A 1-year-old child presenting with developmental delays, special facial features, gastrointestinal bleeding, renal calcium deposition, and hypotonia was admitted to the hospital for "hypercalcemia and gastrointestinal bleeding." Genetic testing showed a deletion mutation in the 7q11.23 region. Currently, the child receiving treatment to promote calcium excretion and rehabilitation training, but hypercalcemia has recurred. CONCLUSION: The clinical phenotype of Williams syndrome is complex, and different severities, characterized by developmental delays, facial deformities, cardiovascular abnormalities, gastrointestinal symptoms and endocrine disorders, should be considered in children. The syndrome may require thorough genetic testing for diagnosis and early intervention treatment to improve patient quality of life.