Answer:
The most likely cause of the boy's bleeding is **vitamin K deficiency**. Vitamin K is essential for the synthesis of several clotting factors, including factor II, VII, IX, and X. Newborns are at risk of vitamin K deficiency because they have low levels of vitamin K at birth and breast milk is a poor source of vitamin K. Vitamin K deficiency can lead to bleeding in various sites, such as the skin, mucous membranes, gastrointestinal tract, and brain⁴.
Factor V Leiden deficiency is a genetic disorder that increases the risk of abnormal blood clots, not bleeding. It is inherited from one or both parents and affects the function of factor V, a protein that helps control blood clotting¹. The mother has factor V Leiden deficiency, but it is not clear if the boy inherited it from her or not. Even if he did, it would not explain his bleeding symptoms.
Factor VIII deficiency and factor IX deficiency are also inherited bleeding disorders, but they are caused by mutations in different genes than factor V Leiden. They affect the function of factor VIII and factor IX, respectively, which are also involved in blood clotting. These disorders are also known as hemophilia A and hemophilia B, respectively⁵. They can cause bleeding into joints, muscles, and internal organs, but they are rare and usually affect males more than females.
Idiopathic thrombocytopenic purpura (ITP) is a condition that causes low platelet count and increased bleeding tendency. Platelets are small blood cells that help form clots and stop bleeding. ITP can be caused by an autoimmune reaction or a viral infection that destroys platelets⁶. However, the boy has a normal platelet count, which makes ITP unlikely.
Liver disease can also cause bleeding problems because the liver produces most of the clotting factors. Liver disease can impair the synthesis and metabolism of these factors, leading to reduced levels and activity. Liver disease can also cause jaundice, which is a yellowing of the skin and eyes due to high levels of bilirubin in the blood. However, the boy has a normal liver enzyme level (alanine aminotransferase) and a mild elevation of bilirubin, which could be due to physiological jaundice of the newborn rather than liver disease.
Therefore, based on the information provided, vitamin K deficiency is the most likely cause of the boy's bleeding. He should receive vitamin K supplementation as soon as possible to prevent further complications. I hope this helps you with your question.