Thanatophoric Dysplasia

Information below from the Genetic Home Reference Website with added notes from me!

What is thanatophoric dysplasia?

Thanatophoric dysplasia is a severe skeletal disorder characterized by extremely short limbs and folds of extra (redundant) skin on the arms and legs. Other features of this condition include a narrow chest, short ribs, underdeveloped lungs, and an enlarged head with a large forehead and prominent, wide-spaced eyes.
Researchers have described two major forms of thanatophoric dysplasia, type I and type II. Type I thanatophoric dysplasia is distinguished by the presence of curved thigh bones and flattened bones of the spine (platyspondyly). Type II thanatophoric dysplasia is characterized by straight thigh bones and a moderate to severe skull abnormality called a cloverleaf skull.
The term thanatophoric is Greek for "death bearing." Infants with thanatophoric dysplasia are usually stillborn or die shortly after birth from respiratory failure; however, a few affected individuals have survived into childhood with extensive medical help.

Jamie Lynn was diagnosed with Type I.  At birth, she presented with a very small chest, tiny arms and legs but with large folds of skin.  Her facial features were consistent with most other dwarfisms.  Large forehead and tiny nose.  Her diagnosis was confirmed by X-rays at birth.  She died an hour and fifteen minutes after she was delivered via c-section.  We opted to not do extraordinary measures so that her time with us was peaceful.  It seems that most of the ladies online have an average of 1-2 hours post birth, but I do know of one baby boy that lived for 75 hours.  As of 2010, there have been only 4 individuals that have survived into childhood.

How common is thanatophoric dysplasia?

This condition occurs in 1 in 20,000 to 50,000 newborns. Type I thanatophoric dysplasia is more common than type II.

Every few months we have a new member on our online support group that either is diagnosed with some sort of dwarfism, usually a fatal form.  In my online world, I have only "met" one mom with Type II since 2009, but several with Type I. 

What genes are related to thanatophoric dysplasia?

Mutations in the FGFR3 gene cause thanatophoric dysplasia.
Both types of thanatophoric dysplasia result from mutations in the FGFR3 gene. This gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. Mutations in this gene cause the FGFR3 protein to be overly active, which leads to the severe disturbances in bone growth that are characteristic of thanatophoric dysplasia. It is not known how FGFR3 mutations cause the brain and skin abnormalities associated with this disorder.
Read more about the FGFR3 gene.

The FGFR3 gene drove me mad during my  pregnancy.  After much investigation, there are actually four dwarfisms linked to FGFR3.  Three which are fatal, and the other one?  Normal dwarfism, known as Achondroplasia.  It appeared that it was all about which Amino acid receptor mutated.  It was so frustrating to know that Jamie could have very well lived if the gene had just been a "tad" different!

How do people inherit thanatophoric dysplasia?

Thanatophoric dysplasia is considered an autosomal dominant disorder because one mutated copy of the FGFR3 gene in each cell is sufficient to cause the condition. Virtually all cases of thanatophoric dysplasia are caused by new mutations in the FGFR3 gene and occur in people with no history of the disorder in their family. No affected individuals are known to have had children; therefore, the disorder has not been passed to the next generation.

Basically, when our babies are conceived, a new mutation occurs.  The experts feel that it is one of those conditions that goes under the heading "Lightning Strikes".  They feel that lightening strikes are so rare and having two strikes is almost unheard of.  This is why we decided to go ahead and try to have another child after Jamie.

 Is it completely impossible to have another baby with TD?  No.  There have been case studies of a woman who had three consecutive TD births.  However, most women I "meet" online with same diagnosis go on to have healthy children.  Does that exclude other possible chromosomal issues?  No!  I won't lie when I say this isn't easy!

 

Where can I find information about diagnosis, management, or treatment of thanatophoric dysplasia?

These resources address the diagnosis or management of thanatophoric dysplasia and may include treatment providers.

• Gene Review: Thanatophoric Dysplasia
• Gene Tests: Thanatophoric Dysplasia

You might also find information on the diagnosis or management of thanatophoric dysplasia in Educational resources and Patient support.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

I would copy all the information linked above, but it is gargantuan!  Our story?  

Diagnosis: 

 Jamie was diagnosed at her 18wk Anatomy Scan (ultrasound).  The radiologist ONLY found shortened limbs of ALL long bones (meaning legs and arms).  He did not note any other irregularities.  He had us consult with our OB for options.  The first diagnosis we were given were actually chromosomal issues.  They included T21 (Down Syndrome), T13, and T18 (both which are pretty fatal).  Our OB suggested that we have an amniocentesis.  Termination of the pregnancy was offered at this point.  We stated that was not an option for us.  And for those who wonder, we are Catholic, but it our religion really didn't play into this fact. 

 My L&D background did.  

We had an amniocentesis done two days later.  We received our phone call from the OB on a Sunday.  Good news?  Yes, the baby's chromosomes were normal, which indicated no T21,T13,T18.   The bad news?  Something was still wrong with her.   

We were directed to our perinatologist.  At our appointment, he scanned our baby and immediately said that he felt that the baby had a fatal dwarfism.  Either OI (Brittle Bone Disease) or TD.  This is where I am going to be honest.  He made this decision pretty quickly and immediately offered termination.  After we expressed our feelings about termination and that we would carry NO matter what, even if the condition was fatal, he finally took more time.  All of a sudden, he felt that he baby (we did not want to know her gender...we like surprises!) might possibly have achondroplasia ("normal" dwarfism).  I only mention this because the medical community seems to be real quick to offer termination. 

 What you don't know?  MOST women opt for termination because they don't know that they CAN continue their pregnancy. 

Off to the Children's Hospital we went.  They did another extensive ultrasound and a Fetal MRI.  We received the results a few weeks later (she was approximately 24wks)  that indicated that Jamie had Thanatophoric Dysplasia with a differential diagnosis of achondroplasia.  

Hindsight?  All we needed was to make sure that the amnio included a genetic mutation screening for dwarfism.  It would have made things so much easier!  That little bit of hope that she had normal dwarfism hung at the back of our heads.  AND there was a possibility that she had a new form of dwarfism.  There are over 200 types of dwarfisms and new ones are diagnosed constantly.

Management?

  The remainder of our pregnancy consisted of numerous ultrasounds to track her growth, my amniotic fluid levels, and her general health.  She was a trooper and would surprise them with her activity inside.  She made fetal breath movements, which indicated that she was trying to breathe.  Her brain always looked healthy and normal, and her heart was strong.  When we reached 28wks, my amniotic fluid levels started to increase.  By 32 wks, we had reached epic proportions!  A normal AFI is about 8-18.  By the end of the pregnancy, we reached 54!   I looked like I was carrying twins, and it started to considerably compromise my breathing (history of asthma) and started taking a toll.  It also indicated that Jamie was expelling too much fluid and not "breathing" which would level the fluid out.  This and the fact that the ventricles started swelling were the catalyst to decide to deliver just shy of 36wks.  Any longer, and she would have been stillborn.

Treatment?  

We had none.  You cannot "fix" the fact that every single cell of her body had this disease.  The reality is that her trunk and head were growing at normal or above normal rates, and her limbs were lagging behind.  By 35+wks, her head was measuring at 41wks and her limbs were still behind 17wks.  Yes, you read that right.  Her limbs never even measured the length that they should have been at her anatomy scan.  It was devastating.

Delivery?  

We had to deliver via c-section due to the fact that she was breech presentation, which seems to be a common theme amongst the moms that I have communicated with.  The fear of a vaginal delivery is that they are likely to have entrapment problems.  Their bodies' would be delivered without difficulty, but their heads could get caught in the pelvic area and cause severe damage.

This actually worked well for us, because we had read that vaginal deliveries can compromise normal dwarfism babies also.  Their tracheas' are so short and can be easily closed off by their larger than normal heads.  We figure this gave us the time with her that we wanted.

Birth? 
 So this brings me to her birth!  We first found out we had a girl.

 We actually had to ask because the L&D staff are so used to parents knowing already!  Our OB wrote in bright red...DO NOT TELL GENDER on our chart.  He even tucked the amniocentesis results in the way back of the chart!  We also

 finally could actually confirm her TD (remember that differential diagnosis of achondroplasia?) by X-ray.  

Her x-ray showed that her lungs were just too small to sustain life.  It was painful, but liberating in so many ways.  We did not have to do superhuman treatments to just prolong a short life.  We wanted to hold her and love her, not watch her in a isolette and not be able to touch her.  She was with us for 75 min.  The most beautiful and painful minutes of my life.

We miss her dearly.

Where can I find additional information about thanatophoric dysplasia?

You may find the following resources about thanatophoric dysplasia helpful. These materials are written for the general public.

• MedlinePlus - Health information (2 links)
• Educational resources - Information pages (3 links)
• Patient support - For patients and families (4 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

• Gene Reviews- Clinical summary
• Gene Tests- DNA tests ordered by healthcare professionals
• ClinicalTrials.gov - Linking patients to medical research
• PubMed- Recent literature
• OMIM - Genetic disorder catalog (2 links)

What other names do people use for thanatophoric dysplasia?

• Dwarf, thanatophoric
• thanatophoric dwarfism
• thanatophoric short stature

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about thanatophoric dysplasia?

Ask the Genetic and Rare Diseases Information Center.

Pass me a note or email me at boysbuttonsandbutterflies@gmail.com

I would love to "chat" with you! Just leave me a note in the comments section!

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

• What does it mean if a disorder seems to run in my family?
• What are the different ways in which a genetic condition can be inherited?
• If a genetic disorder runs in my family, what are the chances that my children will have the condition?
• Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.

• Genetics and health
• Resources for Patients and Families
• Resources for Health Professionals

What glossary definitions help with understanding thanatophoric dysplasia?

autosomal ; autosomal dominant ; cell ; dwarf ; dwarfism ; dysplasia ; gene ; mutation ; new mutation ; protein ; respiratory ; short stature ; stature ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.

References (3 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.