Rickets in an infant with Williams syndrome

Area of Science:

• Pediatric Endocrinology
• Genetics
• Nephrology

Background:

• Williams syndrome is a genetic disorder characterized by multisystem abnormalities.
• Altered calcium homeostasis is a known feature of Williams syndrome, often presenting as hypercalcemia.

Observation:

• A 4-week-old infant diagnosed with Williams syndrome presented with hypercalcemia, hypercalciuria, and medullary nephrocalcinosis.
• Genetic analysis confirmed a deletion of the elastin gene on chromosome 7, consistent with Williams syndrome.

Findings:

• The infant was initially treated with a low-calcium, vitamin D-deficient formula.
• This dietary intervention paradoxically led to the development of rickets.
• Switching to a standard infant formula resulted in the resolution of rickets.

Implications:

• This case highlights the complex interplay between genetic predisposition, calcium metabolism, and nutritional management in Williams syndrome.
• It underscores the importance of individualized nutritional strategies in infants with Williams syndrome to prevent both hypercalcemia and nutritional deficiencies like rickets.
• Understanding these metabolic disturbances is crucial for improving long-term outcomes in affected children.