What is the etiology of ear circumference depression?

  Ear circumference depression is one of the symptoms of pediatric Diegeorg’s syndrome. The facial features of pediatric Diegeorg’s syndrome include a long face, bulbous nasal tip and narrow nasal wings, cleft palate, flattened cheekbones, widened eye spacing, slanted eyes, low hanging ears with depressed ear circumference, and small jaw.  Diegeorg’s syndrome, or congenital absence or hypoplasia, is a primary cellular immunodeficiency disorder. It is a congenital abnormality caused by the absence or underdevelopment of the thymus and parathyroid glands due to an impaired development of the third and fourth pharyngeal sacs during embryonic life. The child is often associated with other congenital malformations.  The syndrome is a polygenic disorder, but deletion of chromosome 22q11 region is the main cause.