Methods of Detection
Methods of Detection
I have no training in this field so I asked an expert to look it over:
Philippe Jeanty, MD, PhD
Inner Vision Women’s Ultrasound
He has a special interest in skeletal dysplasias, and close links with the Little People of America (an organisation for people of restricted growth). He kindly wrote some additional material which should help any medical professional to differentiate between the possible prenatal diagnoses for skeletal dysplasias which have narrow ribcages and polydactyly.
Some parents find out that their child has a problem whilst it is still in utero when they have a detailed ultrasound scan. At this point they will be given a scary range of possible diagnoses, most of them fatal . These are the most likely suspects:
¯ Jeune syndrome (aka asphyxiating thoracic dystrophy, thoracic/pelvic/phalangeal dystrophy) These foetuses do not have the typical polydactyly of EvC and so can be distinguished pretty easily. In spite of the dreadful name, the disorder is not always fatal.
¯ Short rib polydactyly syndrome Type I (aka Saldino-Noonan Syndrome, Polydactyly with neonatal chondrodystrophy type 1)
¯ Short rib polydactyly syndrome Type II (aka Majewski Syndrome, Polydactyly with neonatal chondrodystrophy type II)
¯ Short rib polydactyly syndrome Type III (aka Verma-Naumoff Syndrome, Polydactyly with neonatal chondrodystrophy type III)
¯ Short rib polydactyly syndrome Type IV (aka Beemer-Langer Syndrome, Short rib syndrome Beemer type)
Note - All the short ribs polydactylies have very constricted chests and short ribs. This results in pulmonary hypoplasia (lungs which are too small) which is the cause of death. But prenatally the short ribs result in oesophageal compression (squashing of the gullet) and thus polyhydramnios (excess fluid in the uterus) which is much more severe than in EvC. Furthermore they have polydactyly but with very short and stubby fingers. The fingers in EvC are more tapered at the ends, and not as thick.``````````````````````````````````````````````````````````````````
¯ Thanatophoric dwarfism - Babies with this condition have much shorter long bones (femur, tibia, fibula, humerus, radius, and ulna) and either have a bowed femur or a deformity of the skull called clover-leaf shape. They too have too much amniotic fluid and should be reasonably easy to differentiate from EvC through ultrasound scan.
You will only be given a definite diagnosis of EvC if you have a family history of it. They cannot do accurate genetic tests via chorionic villus sampling or amniocentesis unless they know the exact location of your particular variant of EvC. They will only have this information if they tested the DNA of a previous child. I have read one report where they managed to detect EvC in a foetus as early as 13 weeks with an ultrasound scan, but more normally it is found at 16 weeks plus. If you have a family history of EvC, then they will scan you after 16 weeks to check your baby for 6 fingers and to measure the length of the femur (thigh bone). I don’t think there is a way to tell if your baby will have a big enough rib cage to breathe on his/her own after birth. If your baby is found to have EvC then they will also do a detailed scan of its heart to check for abnormalities there.
After receiving such a bombshell, you will face a tough decision – to continue the pregnancy or not. You can find out more information here:
Neither road is easy, so whatever you decide, I hope you get the love and support you need. This is a sympathetic article about researching your choices:
Some people only find out when their child is born that they have EvC. This is what happened to us. It is very frightening and upsetting to find out that there is something wrong with your precious baby. It doesn’t make them any less precious but it hits like a bolt from the blue. You may well not get a provisional diagnosis for days or weeks, and in some cases months because the doctors don't encounter EvC very often. This leaves most people feeling very worried because they have no idea what to expect for and from their child. When the diagnosis is made, then your child should be referred quickly to a cardiologist to have their heart scanned for problems.
Ultimately the diagnosis of EvC is confirmed
on the basis of x-ray results rather than DNA testing. There is a
characteristic appearance of the hip socket (acetabulum) in babies
with EvC - an acetabular spur. We got Angus’ final
results when he was 7 ½ months old.
This site was last updated 31-Mrz-2009
©Kate Lawrence (BscHons Physiotherapy) 2005