Rodzicielskie uwarunkowania zespołów delecji 22q11.2

Microdeletions 22q11.2 (CATCH 22) can involve variable space of chromosome region 22q11 and is identified commonly as DiGeorge syndrome (DGS), Shprintzen syndrome (velo-cardio-facial syndrome, VCFS) or Takao (CTAFS - conotruncal anomaly face syndrome). Microdeletions 22q11.2 may be familial. In familial cases, the risk of occurence of the abnormality in the next child is greatly increased. The frequency of the familial forms has been reported to be within the wide range of 6-28%. Familial microdeletions are usually transmitted as autosomal dominant trait with variable expression in family members. Cytogenetic and molecular techniques used in diagnosis of the familial transmission. On the basis of accessible data in literature, we analyzed 63 parents transmitting del22q11.2 to their children. The deleted sequence was maternally derived in ∼73% of these cases. One or more of the features characteristic of the deletion 22q11.2 syndrome were found in all parents with del22q11.2; however, the symptoms were weakly expressed. The most frequent signs in the parent (although of weaker expression than in the child), suggesting the possibility of parental transmission, are: mental retardation, nasal tone of the voice and dysmorphic facial features. Predisposition may also manifest itself in adult patients and their parents by psychiatric disturbances such asbipolar disease, schizophrenia and others. The diagnosis of any of the del22q11.2 syndromes in a child requires verification in his parents, if possible by the same physician-specialist. The theoretical risk of the reccurence of the anomaly in next children in the family is in this case 50%. Prenatal diagnosis, usually using FISH (fluorescent in situ hybridization) in successive pregnancies is therefore indicated.