Healing fracture or bone growth: At 1 year old, children are prone to falls and injuries, and their bones are constantly growing. Elevated alkaline phosphatase (ALP) is common in these scenarios due to bone turnover and healing.

Vitamin D deficiency or rickets: Deficiency in vitamin D can lead to increased ALP levels due to the body's attempt to mobilize calcium and phosphate for bone mineralization.
Infectious diseases (e.g., osteomyelitis): Certain infections can cause an elevation in ALP due to the inflammatory response and bone involvement.
Benign bone tumors or cysts: Conditions like osteochondroma or unicameral bone cysts can cause localized elevation in ALP.

Malignant bone tumors (e.g., osteosarcoma, Ewing's sarcoma): Although rare in this age group, these conditions can present with elevated ALP and are critical to diagnose early due to their aggressive nature and potential for metastasis.
Liver disease (e.g., biliary atresia, neonatal hepatitis): While less common, liver diseases can cause elevated ALP levels, especially if there's involvement of the biliary tree.
Hypophosphatasia: A rare genetic disorder characterized by deficient activity of tissue-nonspecific alkaline phosphatase, leading to elevated levels of phosphocompounds in the blood and urine, and can present with bone abnormalities.

Paget's disease of bone: Extremely rare in children, this condition involves an abnormal breakdown and regrowth of bone tissue, leading to elevated ALP levels.
Wilson's disease: A genetic disorder leading to copper accumulation in the body, which can cause liver disease and, occasionally, elevated ALP levels.
Other genetic disorders affecting bone or mineral metabolism: Conditions such as achondroplasia or pseudohypoparathyroidism can also present with abnormal ALP levels, though they are rare and often have distinctive clinical features.