Citrullinemia is a genetic disorder that leads to the harmful buildup of ammonia and other toxic substances in the blood. This condition is categorized into two primary types, each with distinct clinical presentations and underlying genetic causes, highlighting the importance of accurate Citrullinemia Diagnosis for effective management.
Type I Citrullinemia, also known as classic citrullinemia, typically manifests in newborns within the first few days of life. Initially, infants may appear healthy at birth, but as ammonia levels rise, they progressively develop symptoms such as lethargy, feeding difficulties, vomiting, seizures, and even loss of consciousness. In some cases, serious liver complications can also arise. It’s critical to consider citrullinemia diagnosis in newborns presenting with these symptoms due to the life-threatening nature of type I. A milder form of type I citrullinemia can emerge later in childhood or adulthood, characterized by intense headaches, blind spots (scotomas), balance and coordination issues (ataxia), and lethargy. Notably, some individuals with the genetic mutations for type I citrullinemia may remain asymptomatic, underscoring the variability in disease expression and the need for comprehensive diagnostic approaches.
Type II Citrullinemia primarily impacts the nervous system, leading to a range of neurological symptoms. These include confusion, restlessness, memory problems, abnormal behaviors like aggression, irritability, and hyperactivity, as well as seizures and coma. Individuals with type II citrullinemia often exhibit specific food cravings, typically favoring protein and fat-rich foods while avoiding carbohydrates. The onset of symptoms is usually in adulthood (adult-onset type II citrullinemia), and can be triggered by factors such as certain medications, infections, surgery, and alcohol consumption. Recognizing these triggers is important in the diagnostic process. These symptoms can be severe and life-threatening, emphasizing the importance of timely citrullinemia diagnosis in adults presenting with these neurological issues.
Adult-onset type II citrullinemia can also develop in individuals who experienced a liver disorder in infancy known as neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). This condition, also referred to as neonatal-onset type II citrullinemia, disrupts bile flow and impairs nutrient processing.
In many instances, NICCD symptoms resolve within the first year of life. However, in some cases, individuals may experience a recurrence of symptoms in early childhood, even after initial recovery from NICCD. These later symptoms may include delayed growth, extreme fatigue, specific food preferences (as mentioned earlier), and abnormal lipid levels in the blood (dyslipidemia). This condition is termed failure to thrive and dyslipidemia caused by citrin deficiency (FTTDCD). Years or even decades later, individuals with a history of NICCD or FTTDCD may develop adult-onset type II citrullinemia. Therefore, a history of NICCD or FTTDCD can be a significant factor in considering citrullinemia diagnosis in adults with relevant symptoms.
Understanding the different types of citrullinemia, their characteristic symptoms, and potential triggers is crucial for effective citrullinemia diagnosis. Early and accurate diagnosis is essential for timely intervention and management to improve outcomes for individuals affected by this genetic disorder.
