What Are Low Calcium Symptoms in 22q11.2 Deletion?

Children with 22q11.2 deletion syndrome often experience hypocalcemia (low levels of calcium in the blood), which can cause invisible but dangerous complications ^[1]. This happens because the parathyroid glands—four tiny glands in the neck that control calcium levels—often do not develop properly before birth ^[1][2]. Without fully functioning parathyroid glands, your child’s body struggles to keep enough calcium in their blood, a condition known as hypoparathyroidism ^[3].

Low calcium can happen at any age, even if your child has previously had normal calcium levels ^[4]. Because a severe low calcium episode can become a medical emergency, it is crucial to know exactly what signs to watch for so you can seek prompt care.

Physical Signs of Low Calcium

The symptoms of a low calcium episode can range from mild to severe, depending on how quickly and how significantly the calcium levels drop. Because young children cannot always explain what they are feeling, parents should watch closely for these physical signs:

• Tingling and Numbness (Paresthesia): This often starts as a “pins and needles” sensation around the mouth, lips, or in the fingers and toes ^[5][6].
• Muscle Cramps and Pain: You might notice your child complaining of severe muscle aches, stiffness, or spasms, particularly in their legs, arms, or abdomen ^[7].
• Fatigue and Irritability: While harder to pinpoint, extreme fatigue or sudden changes in mood and irritability can be early warning signs ^[5].
• Tetany: This is a severe form of muscle spasm where the muscles involuntarily contract and lock. Most commonly, you might see your child’s hands or feet cramp inward in an unnatural position (carpopedal spasms) ^[8][9].
• Breathing Difficulties: In serious cases, low calcium can cause spasms in the throat (laryngospasm) or airways (bronchospasm), making it hard to breathe ^[9][10]. This is a medical emergency requiring immediate attention (such as calling 911).
• Seizures: If calcium drops too low, it can trigger generalized convulsions or seizures ^[9]. This is also a medical emergency requiring immediate medical care.

What Triggers a Low Calcium Episode?

Your child’s body uses more calcium during times of physical or physiological stress. Because underdeveloped parathyroid glands cannot ramp up hormone production to meet this higher demand, blood calcium levels can suddenly plunge ^[11][12]. Common triggers for a hypocalcemic episode include:

• Illnesses and Infections: Even common childhood viruses or fevers place stress on the body and can deplete calcium stores or trigger an imbalance ^[12].
• Growth Spurts and Puberty: Periods of rapid skeletal growth, such as during adolescence, require immense amounts of calcium, frequently unmasking hypocalcemia that had previously gone unnoticed ^[13].
• Surgery: Any surgical procedure is a major physical stressor that can cause a severe drop in calcium ^[11].
• Certain Medications: Medications sometimes prescribed for children with 22q11.2 deletion syndrome, including specific anti-seizure drugs (like phenytoin) and psychiatric medications, can interfere with calcium balance ^[14].

Preparing for Episodes

While you cannot always prevent a low calcium episode, you can be prepared. It is vital to work with your child’s medical team to create a proactive action plan. Ask your endocrinologist what specific steps you should take if you notice mild signs (like tingling or muscle cramps), and clarify exactly when you should head to the emergency room versus calling the clinic. Many families find it helpful to establish a “sick-day protocol” for managing routine illnesses, and to carry a standardized emergency care letter to share with school nurses and teachers so that everyone knows how to spot these symptoms early.