DiGeorge syndrome; velocardiofacial syndrome; pharyngeal pouch syndrome

Introduction

Congenital anomaly of the 3rd & 4th pharyngeal pouches. Absence of thymus & parathyroids.

Pathology

• absence of thymus & parathyroids
• deformities of the ear, nose, mouth
• structural & functional palate anomalies
• facial anomalies
• cardiac
  • interrupted aortic arch
  • tetralogy of Fallot
  • persistent truncus arteriosus 6 immunodeficiency

Genetics

• most cases result from a deletion of chromosome 22q11.2 (the DiGeorge syndrome chromosome region)
• associated with defects in TBX1
  • haploinsufficiency of the TBX1 gene is responsible for most of the physical malformations present in DiGeorge syndrome & velocardiofacial syndrome
  • these two syndromes represent two forms of clinical expression of the same entity manifesting at different stages of life
• may be role for HIRA, LZTR1, DGCR13, GSC2, DVL1L1

Clinical manifestations

• congenital heart defects
• immunodeficiency secondary to thymic hypoplasia
• hypocalcemia secondary to hypoparathyroidism due to parathyroid gland hypoplasia
• deformities of the ear, nose, mouth, palate

Laboratory

• hypocalcemia

More general terms

• immunodeficiency; immunodeficiency syndrome
• hypoparathyroidism
• developmental disorder syndrome (multisystem disorder)
• genetic syndrome (multisystem disorder)

Additional terms

• Shprintzen syndrome; velocardiofacial syndrome

Database

• OMIM: https://mirror.omim.org/entry/188400
• OMIM: https://mirror.omim.org/entry/601225