Congenital unilateral hypoplasia of depressor anguli oris

Congenital unilateral hypoplasia of the depressor anguli oris (CUHDAO), also known as asymmetric crying facies or congenital hypoplasia of the depressor anguli oris muscle (DAOM), is a relatively common congenital anomaly characterized by the absence or underdevelopment of the depressor anguli oris muscle on one side of the face. This muscle is responsible for pulling the corner of the mouth downward. The condition becomes most apparent when the infant cries, as the unaffected side of the mouth pulls downward normally while the affected side remains relatively stationary or moves upward, creating a characteristic facial asymmetry. At rest, the face typically appears symmetric. CUHDAO is often an isolated finding but is clinically significant because it can be associated with other congenital anomalies, particularly cardiovascular defects (such as ventricular septal defects and other heart malformations), genitourinary anomalies, musculoskeletal defects, and, less commonly, central nervous system abnormalities. This association is sometimes referred to as Cayler cardiofacial syndrome when cardiac defects are present. It is important to distinguish this condition from facial nerve palsy, which involves broader facial muscle weakness. The diagnosis is primarily clinical, based on observation of the characteristic asymmetric crying facies. Electromyography (EMG) can confirm the absence or hypoplasia of the depressor anguli oris muscle. Given the association with other congenital anomalies, a thorough evaluation including echocardiography and renal ultrasound is recommended for affected infants. Some cases have been associated with microdeletions at chromosome 22q11.2, overlapping with DiGeorge syndrome/velocardiofacial syndrome. No specific treatment is required for the facial asymmetry itself, as it tends to become less noticeable with age. Management focuses on identifying and treating any associated congenital anomalies, particularly cardiac defects. In rare cases where cosmetic concerns persist, surgical intervention may be considered later in life.

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