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Thanatophoric Dysplasia
Tuesday, 11 January 2005
Tuesday, 11 January 2005


Thanatophoric dysplasia is a form of dwarfism that is often lethal shortly after birth because of severe breathing problems. These children have many skeletal abnormalities so it may be detected during a prenatal ultrasound. There are two types, with type 1 being more common than type 2, but the outcome does not vary between them.


This disease occurs equally in males and females, and in about 1 child per 10,000-50,000 live births. It is not inherited in the vast majority of cases, but occurs because of a change in a specific gene in the egg or sperm that created the child. Since it is not thought to be inherited, the risk of having another child with the same condition is not significantly increased relative to other unaffected families. Parents have no control over whether their child develops the gene, and it is no one’s fault.

Signs and Symptoms

Infants with this condition have very short arms and legs with severely abnormal bones. Those with type 1 usually have a normally shaped head, but have curved long bones (for example, the thigh bones). Those with type 2 usually have a cloverleaf-shaped head, but have straight long bones. However, there is some overlap between the two types. Children with either type 1 or type 2 can have short ribs, a narrow chest but protuberant abdomen, a large head with enlarged fluid cavities (ventricles) within the brain, spinal bone abnormalities, and extra skin folds on the arms and legs. There are also specific facial features. There may be an abnormal number of fingers, and the fingers may be shortened. Since the skull is not properly formed, there is often compression of vital brain structures. The brain is also not normally formed, and there may be heart and kidney problems as well. After birth, these children generally have severe breathing problems, likely due to the small chest cavity, underdeveloped lungs, compression of vital brain structures controlling breathing, or a combination of these factors.

Possible Causes

This condition has been linked to mutations (breaks) in a specific gene called FGFR3. This gene is important for its many effects on cell growth and maturation. Both type 1 and type 2 dysplasias are associated with mutations in this same gene, but the specific mutations differ between the two types.


Thanatophoric dysplasia is generally diagnosed by clinical examination, or certain findings on prenatal ultrasound and imaging studies. Special molecular tests are available to confirm the diagnosis by looking for specific FGFR3 gene mutations.


Unfortunately, there is no cure for this disease. If aggressive treatment is deferred, palliative (comforting without curing) treatment includes keeping the infant warm, comfortable and nourished. In the rare cases of long term survivors, these children require breathing support with a ventilator (a machine assists breathing via a tracheostomy, a surgically placed hole in the front of the neck). Also, hearing aids may be needed for hearing loss. If the child has seizures, medications can be given. Various surgeries may be considered for brain and skull abnormalities. Orthopedic evaluation for joint problems may also be explored.


Pregnancy with an infant with thanatophoric dysplasia can be complicated by premature birth, excess amniotic fluid around the infant (polyhydramnios), abnormal positioning in the uterus (for example, laying sideways or buttocks down in the breech position rather than head down), and/or inability for the infant to be born vaginally due to the head being too large and/or the neck being in a rigid abnormal position. Most infants with this condition die within the first few hours or days. Parents are faced with decisions regarding the degree of extreme life support measures that they desire for their child. Although there have been rare cases of long term survivors, (children ages 3, 4, and 9 years old have been described, in addition to a 47 year old woman), all have required breathing assistance by a machine, a great deal of medical help, and have some degree of neurologic abnormality and mental retardation in addition to the skeletal abnormalities.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.


National Library of Medicine Genetics Home Reference Provides information on the disease and genetic conditions in general, helpful resources and family support, genetics specialists by geographic area, and a glossary of related terms. Need to input the topic name into the search box. The Compassionate Friends Committed to helping families achieve positive grief resolution after the loss of a child. Contains supportive brochures, sibling resources, a chat room, and links to other grief resources. Sponsors a national magazine and conference. HAND: Helping After Neonatal Death Created to help families cope with the loss of a baby. Provides supportive comments, resources, and suggestions for grieving parents and families. Also includes a list of support groups, a book list, a newsletter, and a listing of related websites. International Skeletal Dysplasia Registry Created in 1970, this is the largest such registry in the world. Provides information regarding research, and how to make an appointment with their experts. Contains links to Cedars Sinai Medical Center’s Prenatal Diagnosis Center and Medical Genetics Institute. Little People of America An organization for people of short stature, it provides abundant information and support for families affected by various forms of dwarfism. There are regional chapters, a newsletter, and national conferences. Includes a chat room and online discussion groups. Baby Center Under “Pregnancy Boards”, there is a bulletin board entitled “Grief and Loss”. This section contains a board entitled “Termination for Medical Reasons”. There are several postings here from women who’s babies were diagnosed with thanatophoric dysplasia, and other serious medical conditions, and the different choices they made for their children. Through connection with others, provides support for grieving families.

Google Search for Thanatophoric Dysplasia

References and Sources

Gene Reviews: OMIM: Emedicine: