Symptoms usually begin within the first 2 years of life, with the loss of head control and the ability to sit, crawl, or walk, accompanied by deterioration in vision and speech. Some children may have seizures. Distinctive facial deformities may be present at birth, including a prominent forehead, crossed eyes, an unusually small nose or jaw, and large, low-set ears. INAD is an autosomal recessive disorder, which means that both parents must be carriers of the defective gene that causes INAD to pass it on to their child.
Disclaimer