Costello syndrome is a rare multisystem disorder; only about 300 cases have been reported worldwide. It was first described in 1971, and is also known as faciocutaneoskeletal or FCS syndrome.
What are the clinical features of Costello syndrome?
Children with Costello syndrome have a distinctive facial appearance. They are short in stature. They have feeding difficulties at birth resulting in failure to thrive. There are heart defects, developmental disabilities and a tendency to grow tumours. However they tend to be happy, sociable children.
The following features may arise prior to birth.
- Polyhydraminos (excessive amniotic fluid)
- Fetus heavier than expected for gestational age, due to swelling
- Fetal distress including tachycardia (fast heart beat)
- Short limbs noted on fetal ultrasound examination
The table below describes the most common features of Costello syndrome.
What causes Costello syndrome?
Costello syndrome is due to a genetic defect that is inherited in autosomal dominant manner. However, almost all cases described have resulted from new mutations in the HRAS gene, as individuals with Costello syndrome are unlikely to have children.
The HRAS gene provides instructions for making the H-Ras protein, which helps control cell growth and division. Mutation causes a permanently active HRAS protein which directs cells to grow and divide constantly. This leads to the growth of benign and malignant tumours.
How is Costello syndrome diagnosed?
Costello syndrome is mainly a clinical diagnosis, but may be confirmed by specialist laboratories that can test for specific mutations in HRAS gene.
What is the treatment for Costello syndrome?
Treatment may be required for specific disorders, such as:
- Tube feeding in infancy
- Physiotherapy for musculoskeletal problems
- Surgery for heart defects and tumours
- Cryotherapy of facial papillomas
As the children grow older, it is important to screen for benign and malignant tumours so they can be treated at an early stage. The following procedures may be done at intervals:
- Abdominal and pelvic ultrasound
- Urine analysis for blood
There is no cure for the condition.