DiGeorge syndrome

The term microdeletion 22q11 various disturbances are referred to, which, accompanied by changes on the long arm of chromosome 22 at position 11.

Synonyms

Below are summarized including the DiGeorge syndrome and Shprintzen syndrome ( velo - cardio- faziales syndrome), which show by their different forms smooth transitions into each other. Sometimes the term is used CATCH 22 syndrome. CATCH 22 stands as an acronym for "cardiac anomalies " (heart failure), "abnormal facies " ( facial malformations ), " thymic hypoplasia " ( underdevelopment of the thymus ), " cleft palate" ( cleft palate ), " hypocalcemia " ( calcium deficiency in the blood), so for the main symptoms, and 22 for the site of the deletion on chromosome 22q11.2. The term " CATCH -22 ", however, is negatively affected and may impede the acceptance and processing of diagnosis by the affected families unnecessarily. Following a successful novel is Catch-22 often with "dilemma" or " impasse " ( "catch- 22 " situation ) associated. The name should therefore be avoided.

Symptoms

Because of microdeletions on the long arm of chromosome 22 ( 22q11 ) already occurs during pregnancy in child developmental disorders ( defective development of the 3rd and 4th pharyngeal pouch ). These can be in various degrees of severity to heart defects (eg, ventricular septal defect ), malformations of the vessels ( eg in the area of the aortic arch, as Aortenhypoplasie ), agenesis of the parathyroid glands ( hypoparathyroidism ), lack of training or education of a minor thymus ( thymic aplasia or thymic hypoplasia ), and facial malformations (eg, cleft lip and cleft palate ) lead. In approximately one third of cases also kidney investments occur.

The symptoms are determined by the different degrees of severity of the individual features. Facial deformities such as a cleft lip and palate are often conspicuous already in the context of prenatal diagnosis by ultrasound. Furthermore occurring facial malformations are: relatively broad nasal bridge, long nose, broad nasal tip, widely spaced eyes ( hypertelorism ), downslanting Lidachse, epicanthus, short philtrum and Ohrmuscheldysplasie.

Severe heart failure and vascular malformations are, if not already discovered prenatally, usually some time after birth by the typical symptoms and an ultrasound of the heart ( echocardiography). Typically occurring heart defects are mainly aortic arch, but also a truncus arteriosus communis, a tetralogy of Fallot or ventricular septal defect a.

The thymic hypoplasia can cause by the lack of formation of T - lymphocytes to serious infections of the child and generally increased to a susceptibility to infection (see Immune Deficiency ). If sufficient residual function of the thymus present, is often observed no increased susceptibility to infection.

The absence or deficiency of parathyroid hormone that is produced in the parathyroid gland, it can carry the resulting calcium deficiency cause seizures ( tetany ) come (see also hypoparathyroidism ).

Since it is a collective term for various deletions at 22q11 Mikrodeletionsyndrom, must not in any case, all symptoms and they can vary in strength.

Diagnosis

A presumptive diagnosis is made by the combined occurrence of typical malformations. Certain congenital malformations at heart are often the first indication. The suspicion can be confirmed by molecular cytogenetic diagnostics and detection of 22q11 deletion. Here, the fluorescence in situ hybridization (FISH ) is the method of choice. A 22q11 deletion may be familial, so the parents of an affected child should also be investigated if they wish, since a recurrence risk can be weighed for subsequent pregnancies in this way.

Therapy

Due to the genetic cause of the causal cure is not possible. However, is indicated is a symptomatic therapy, in particular the correction of deformities occurring and the treatment of comorbidities. This involves surgical correction of heart defects, calcium and vitamin D supplementation and a possible Thymustransplantation.