EP09.73: When fetal ultrasound leads to the diagnosis of DiGeorge microdeletion in the parent

DiGeorge syndrome also known as velocardiofacial syndrome caused by the heterozygote deletion of the long arm of chromosome 22 (22q11.2) is one of the most common microdeletion syndromes. The prevalence is estimated to be 1 in 3000-6000 live births but some data suggest it to be more common. Most cases are de novo chromosomal aberrations but around 10% are inherited by an autosomal dominant pattern. The aim of our report is to present two families in which the diagnosis of the mother was based on fetal ultrasound. Case report of two families. Case 1: at the 12th week scan truncus arteriosus communis was suspected by abnormal 3 vessel view and fetal cardiologist subsequently confirmed the diagnosis in the fetus. Genetic counselling revealed that the parents lost their first child at the age of 4 months who underwent cardiac surgery also for truncus arteriosus communis. Amniocentesis was offered, conventional cytogenetic testing showed normal fetal karyotype and MLPA analysis detected 22q11.2 microdeletion. Based on the family history and some typical minor anomalies detected in the mother further testing was advised and the mother proved to be also heterozygote for 22q 11.2 microdeletion by FISH method. Despite the relatively poor prognosis of the cardiac defect after consultation with neonatal cardiologist, cardiac surgeon and clinical geneticist the couple decided to continue the pregnancy and it is still going on. Case 2: right aortic arch was detected at the 13th week in the fetus. Amniocentesis proved normal fetal karyotype and MLPA analysis detected a heterozygote deletion in the 22q11.2 region. The mother showed mild velopharyngeal incompetence without any further medical problem and by FISH proved to carry the 22q11.2 microdeletion. This pregnancy is also still going on. Our cases point out the importance of extended fetal cardiac examination in the first trimester.