SNP Shot: Genomic Insights

Neuroblastoma is a cancer primarily affecting children, arising when immature nerve cells, called neuroblasts, become abnormal and proliferate uncontrollably, forming a tumor. The most common site of origin is the adrenal gland, located above each kidney. However, tumors can also develop in nerve tissue within the abdomen, chest, neck, or pelvis. Neuroblastoma can spread (metastasize) to other areas of the body, including the bones, liver, or skin.

Symptoms of neuroblastoma vary. General symptoms may include irritability, fever, fatigue, pain, appetite loss, weight loss, or diarrhea. More specific symptoms depend on the tumor's location and any spread. For instance, an abdominal tumor can cause swelling in the abdomen, while a chest tumor may lead to breathing difficulties. A neck tumor could cause Horner syndrome, characterized by drooping eyelids, small pupils, reduced sweating, and reddened skin. If the cancer has spread to the bone, symptoms may include bone pain, bruising, pale skin, or dark circles around the eyes. A tumor pressing on the spinal cord can result in weakness, numbness, or paralysis in the arms or legs. Blue or purple skin bumps, resembling blueberries, suggest skin metastasis.

Furthermore, neuroblastoma tumors may release hormones, leading to symptoms like high blood pressure, rapid heartbeat, skin flushing, and excessive sweating. Rarely, patients with neuroblastoma can develop opsoclonus myoclonus syndrome, marked by rapid, involuntary eye movements and jerky muscle movements. This syndrome arises when the immune system mistakenly attacks nerve tissue.

Neuroblastoma is most common in children under 5 years old and is rare in adults.

Inheritance:

The majority of neuroblastoma cases are sporadic, meaning they result from mutations occurring in the body's cells after conception (somatic mutations) and are not inherited. Approximately 1-2% of cases are familial neuroblastoma, which follows an autosomal dominant inheritance pattern. This means that inheriting one copy of a mutated gene from a parent increases the risk of developing neuroblastoma. However, this inheritance has incomplete penetrance, meaning that not everyone who inherits the mutated gene will develop the condition. Carrying the gene creates a predisposition to neuroblastoma, but an additional somatic mutation is likely required to trigger the disease.