ATD is characterized by abnormal development of the rib cage (thorax) resulting in a small thoracic cavity. The characteristic “bell-shaped” chest cavity restricts the growth of the lungs and results in a variable degree of lung Hypoplasia and breathing problems (respiratory distress) in the newborn period.
Other clinical features that can be apparent at birth include too many fingers and/or toes (polydactyly), mild to moderate shortening of the long bones of the arms and legs (micromelia), insufficient growth of the pelvic bones, and cardiac defects.
Patients typically present in the newborn period with variable degrees of respiratory distress and recurrent respiratory infections. These breathing problems are the most serious complications of ATD and are the main cause of mortality in these patients. Some reports indicate that 50-60% of children with ATD die in infancy or during the first few years after birth. For those patients that live into early childhood, the breathing problems tend to improve with age such that a subset of patients may live into adolescence or adulthood.
Other complications of ATD can occur as the child grows including: high blood pressure, renal cysts, pancreatic cysts, and, less commonly liver diseases, dental abnormalities, and reduced or deteriorating vision (retinal dystrophy).
Affected individuals may develop chronic nephritis (a kidney condition) that may lead to kidney failure or malfunctions. Heart abnormalities and narrowing of the airway may also occur.