What are the symptoms? Characteristic features include: low birth weightheart defectsstructural eye defectscleft lip and/or palatemeningomyelocele (a spinal defect; see entry Spina Bifida)omphalocele (abdominal defect; see entry Abdominal Exstrophies)abnormal genitalialow-set earsabnormal palm creasesscalp defectsextra digits and overlapping of fingers over thumbabnormal brain development (holoprosencephaly)learning disability How is it diagnosed? Patau syndrome is often detected during pregnancy (see prenatal diagnosis) and some parents will opt not to continue the pregnancy. In some cases a spontaneous miscarriage will occur. Sometimes a baby may be born with features of Patau syndrome after normal scans in the pregnancy. In this situation, a blood sample from the baby will be sent for karyotype analysis to confirm the diagnosis. How is it treated? Parents should meet with the obstetric and neonatal teams to discuss the diagnosis and to prepare for delivery and the care of their baby. It is likely that the baby will be admitted to the special care baby unit, and will require supportive treatments over the first days of life. Many babies with Patau syndrome have congenital problems such as a cleft lip/palate or heart defects. They will need treatments to alleviate symptoms and improve their quality of life. Sadly, many children with Patau syndrome will be lost during a pregnancy, are stillborn or do not survive past the first week of life. A few children will live longer than one year and there are some cases of adults with this condition. If a baby is well enough to leave hospital, community support arrangements should be put in place, and follow-up plans made with the local paediatric team. Inheritance patterns and prenatal diagnosis Inheritance patternsPatau syndrome usually happens as ‘one off’ (sporadic) event in a family. In this situation the chance of another baby with Patau syndrome in the family is low. In rare cases, a balanced translocation in a parent can give rise to an unbalanced translocation in their child. This situation is detected on the baby’s karotype. Prenatal diagnosisScreening for Patau syndrome is now offered at 10-14 weeks of pregnancy using a combined blood test and ultrasound scan as part of antenatal care. If this screening test gives a high risk result a further definitive test (chorionic villous sample test or amniocentesis) is offered. Features of Patau syndrome can be detected on the routine detailed anomaly scan at 20 to 22 weeks gestation (see prenatal diagnosis section) in around 80% of cases. In this situation a definitive chromosome test will be offered. Parents may opt not to continue with the pregnancy. In many cases the baby is lost as a spontaneous miscarriage. Is there support? Information and support in the UK for Patau syndrome is provided by SOFT UK (see entry Edwards’ syndrome).