We observed ankyloglossia to be usually accompanied by displacement of the epiglottis and larynx. Infants with this disease developed dyspnea and skin and hair abnormalities. In addition, they had other symptoms, such as a dark forehead, a frowning expression, a dark color around the lips, scanty eyebrows, swelling around the palpebrae, harsh respiratory sounds, hard crying, snoring, and frequent yawning. In spite of these abnormalities, they had been considered to be healthy by their pediatricians. Arterial oxygen percent saturation (SaO2) was measured while the infants were asleep, suckling, and awake. The results revealed that their SaO2 was unstable and slightly low. The symptoms and signs of this disease were very similar to those observed in victims of sudden infant death syndrome before their death. Correction of the ankyloglossia and deviation of the epiglottis and larynx resulted in great improvement of these signs as well as a stabilization and increase of SaO2.