Hypochondroplasia Research Paper
HYPOCHONDROPLASIA
Crystal Tucker
Developmental Disabilities
Friday, October 4, 2013
What is Hypochondroplasia
Hypochondroplasia, is an autosomal dominant disorder, which is caused by the mutation in the fibroblast growth factor receptor 3, also known as FGFR3, located on chromosome 4. It remains unclear at this time as to how these mutations lead to the features one inherits from having hypochondroplasia, there are researchers who believe that the cause may be due to these genetic changes causing the protein to be overly active, thus interfering with the skeletal development. This, in the end leads to the disturbances in bone growth which are the characteristics of this disorder. Individuals …show more content…
living with the condition are known to have a completely normal life expectancy. In simpler terms, hypochondroplasia is a genetic form of short stature, which belongs to a class of dwarfism. This is a result of a problem with bone formation or growth. Individuals with hypochondroplasia show a disproportion in arms and legs, being shorter than the average size. Only 70% of hypochondroplasia cases are caused by the mutation of the FGFR3 gene. It is believed that the other 30% of remaining cases are caused by the individual having another FGFR3 gene, which is inherited in an autosomal dominant manner. There is a 50% chance that a person with this condition will pass it on to each child, this is of course more common if both parents are affected.
If a child is born with 2 altered copies of the FGFR3 gene (meaning both parents are affected), they tend to have more severe problems with bone growth then a child would if it were born with just 1 FGFR3 mutation. However, a child can be born with hypochondroplasia to average size parents. This happens due to a new chance change (mutation), meaning that the risk of this happening again is virtually zero. Hypochondroplasia, is just one of many in a family of bone dysplasias which are caused by the same mutation in the FGFR3 gene. Some examples of other conditions in this family are, achondroplasia (which is the closest to hypochondroplasia but more severe), SADDAN syndrome, and thanatophoric dysplasia. Hypochondroplasia however, is known to be the mildest in this particular series of related conditions. Common features of one with hypochondroplasia are, short arms, short legs, broad, short hands and feet, large head, limited range of motion at the elbows, sway of the lower back, and bowed legs. It is estimated that 1 in every 15,000 to 40,000 newborns are born with hypochondroplasia each year, in the USA alone. This works out to only 0.01% of the population. One site reports that there are approximately 180,000 to 312,000 known live births, to …show more content…
date.
Health Conditions Associated With Hypochondroplasia
GROWTH An individual with hypochondroplasia, will reach a total adult height of 3’10” to 5’5” (118-165cm). The median height for people with this condition is usually 4’8”. Sometimes the diagnosis of this condition can be delayed due to growth being so close to normal, in the first 3 years of life. Parents should pay close attention to the other health conditions associated with this condition, in order to catch the diagnosis early enough so that they can deal with the potential problems to come. Some may choose to use a growth hormone however; this has a very minimal effect, if any.
HEAD GROWTH About 50% of children with hypochondroplasia also have macrocephaly, meaning their head is abnormally large. This condition is diagnosed when the circumference of the child’s head is more than two times the average size for children of their same age, race, sex, and period of gestation. Regular neuroimaging should be done if the growth of the child head accelerates or if signs and symptoms of hydrocephalus (which is caused by the buildup of cerebrospinal fluid) occur. In some more severe cases, ventriculoperitoneal shunting is performed. Signs and symptoms to watch for when determining if one has hydrocephalus are, abnormal gait, urinary incontinence, and dementia.
SEIZURES Seizures are evident in only a small number of hypochondroplasia cases, this being number being near 5-10%. However, in almost all of these cases individuals also have temporal lobe dysgenesis, which is a structural abnormality of the brain. The standard treatments used for individuals with epilepsy can be used by those with hypochondroplasia, for the treatment of seizures.
Health Conditions Associated with Hypochondroplasia (Cont’d)
DEVELOPMENT Near half of individuals with hypochondroplasia are diagnosed with a learning disability, 10-12% of these individuals have a secondary diagnosis of mental retardation.
Special programing and teachers directed to an individual’s specific needs are available for those who require the assistance.
EARS & HEARING Many children with hypochondroplasia (unfortunately it is not known exactly how many at this point in time), will develop middle ear dysfunction. This can be recurrent and persistent and is accompanied by conductive hearing loss. If this is not treated right away it can lead to delays in one’s language and speech. A surgical incision into the eardrum, in order to relieve pressure or drain fluid (also known as myringotomy) can be performed, including tube placement. However, if a child is in need of ventilation tubes, they should be maintained until the age of 8 years.
LIMITED ELBOW EXTENSION The average person has an elbow extension of 150˚, for an individual with hypochondroplasia however, a limitation of 20˚ to 60˚ is common. This effects ones effective reach, making it difficult to perform certain tasks (e.g. for toileting). One with these limitations can use adaptive devices if necessary (e.g. bottom wiper for
toileting).
VARUS DEFORMITY About 10-12% of those with hypochondroplasia, have progressive varus at the knees and the mesial segments of the legs (an oblique displacement of part of the limb, toward the midline). If ones joints become significantly out of position and is accompanied by pain, surgical intervention is needed. Surgical options include the use of 8-plates, epiphysiodesis, and open osteotomies.
Can You Cure Hypochondroplasia
There is no cure for hypochondroplasia however, some symptoms of this condition can be managed. There is however, an experimental treatment to try and increase the final adult height of individuals with this condition. This treatment is “Limb-lengthening therapy”, which is very long, costly, and is accompanied with complications such as; pain, infections, and nerve problems. This procedure can increase the overall height by 12-14” (30.5 to 35.16cm). This treatment is not usually recommended, seeing as it is still in the experimental stages.
Children Living With Hypochondroplasia
Although there is no cure for hypochondroplasia, this is not a bad thing. Individuals born with this condition are just the same as you and I, and it is important that they know this.
Like all children living with visible physical differences, children with hypochondroplasia can have problems at school and socially fitting in. Although we all wish problems of this sort did not exist, they unfortunately do. However, support groups such as, “Little People of America”, can be a great source of guidance for these children and can teach them how to cope and deal with these unfortunate issues. It is especially important that children with hypochondroplasia, or children living with any sort of developmental disability for that matter, not be limited to school activities, so long as they pose no danger. In order for these children to feel good and not feel, “different” (so to speak), they need to interact with other children and engage in social activities.
Conclusion
Hypochondroplasia is not so common but when we look at it as a “family”, including all disorders in the “bone dysplasias” family, it is in fact a lot more common. It is important that we know and understand the problems individuals living with these conditions face, if not to help them, at least to help understand them better. It is hard for anyone in the world who feels “different”, and it is our job to help take those feelings away, having a great understanding of these individuals conditions and other health issues they may be living with, will help us to do that. By reading the “health issues associated with hypochondroplasia” section in my report, you saw that a lot of these conditions can happen to any one of us, not all together of course but, we are still all subject to these complications, this just proving exactly how much we are all alike. Another point worth thinking about is that any one of us could take part in creating the beautiful life of a baby with hypochondroplasia, even if both you and your partner are of average height, this does not exclude you from this occurrence. With that being said, it is important that we educate ourselves not only on this particular condition but to all of those in the “developmental disability” family, you never know if that baby growing inside you will be born with a certain condition so, educate yourself so that you are prepared to care for this new beautiful life you have created.
Work Cited From:
1. http://www.nemours.org/service/medical/skeletaldysplasia/hypochondroplasia.html?tab=about&kidshealth=45743
2. http://www.healthofchildren.com/M/Macrocephaly.html
3. http://emedicine.medscape.com/article/1150924-overview
4. http://ghr.nlm.nih.gov/condition/hypochondroplasia
5. http://www.sickkids.ca/PaediatricLaboratoryMedicine/Laboratories-Services/Molecular-Genetics-Laboratory/Test-Services-Available/Achondroplasia-Hypochondroplasia.html
6. http://www.healthline.com/galecontent/hypochondroplasia
7. http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=9&ved=0CGcQFjAI&url=http%3A%2F%2Fwww.lpaonline.org%2Fassets%2Fdocuments%2FNH%2520Hypochondroplasia1.pdf&ei=2c1NUpvePJL3yAH694HwBQ&usg=AFQjCNHbaBuBy-cULmDY4LJbDUZur2PKaA&bvm=bv.53537100,d.aWc
8. http://health.yahoo.net/galecontent/hypochondroplasia/5
Glossary of Terms
Achondroplasia – A form of disproportionate stature caused by changes in the same gene as hypochondroplasia.
Thanatophoric Dysplasia - A severe skeletal disorder characterized by extremely short limbs and folds of extra skin on the arms and legs.
SADDAN Syndrome - Is a rare disorder of bone growth characterized by skeletal, brain, and skin abnormalities.
Ventriculoperitoneal Shunting - Surgery to treat excess cerebrospinal fluid (CSF) in the brain.
Macrocephaly - An abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical.
Hydrocephalus - A condition in which fluid accumulates in the brain, typically in young children, enlarging the head and sometimes causing brain damage.
Abnormal Gait - Is a deviation from normal walking (gait).
Urinary Incontinence - Inability to control the flow of urine and involuntary urination
Dementia - A chronic or persistent disorder of the mental processes caused by brain disease or temporal lobe dysgenesis
Myringotomy - Surgical incision into the eardrum, to relieve pressure or drain fluid
Varus Deformity - Weight bearing on outside of foot.
Epiphysiodesis - Staples or 8 plates are placed in the growth plates in the femur near the knee to stop the bone from growing temporarily or permanent
Open Steotomies – Reshaping a bone
Crystal Tucker
Developmental Disabilities
Friday, October 4, 2013
What is Hypochondroplasia
Hypochondroplasia, is an autosomal dominant disorder, which is caused by the mutation in the fibroblast growth factor receptor 3, also known as FGFR3, located on chromosome 4. It remains unclear at this time as to how these mutations lead to the features one inherits from having hypochondroplasia, there are researchers who believe that the cause may be due to these genetic changes causing the protein to be overly active, thus interfering with the skeletal development. This, in the end leads to the disturbances in bone growth which are the characteristics of this disorder. Individuals …show more content…
living with the condition are known to have a completely normal life expectancy. In simpler terms, hypochondroplasia is a genetic form of short stature, which belongs to a class of dwarfism. This is a result of a problem with bone formation or growth. Individuals with hypochondroplasia show a disproportion in arms and legs, being shorter than the average size. Only 70% of hypochondroplasia cases are caused by the mutation of the FGFR3 gene. It is believed that the other 30% of remaining cases are caused by the individual having another FGFR3 gene, which is inherited in an autosomal dominant manner. There is a 50% chance that a person with this condition will pass it on to each child, this is of course more common if both parents are affected.
If a child is born with 2 altered copies of the FGFR3 gene (meaning both parents are affected), they tend to have more severe problems with bone growth then a child would if it were born with just 1 FGFR3 mutation. However, a child can be born with hypochondroplasia to average size parents. This happens due to a new chance change (mutation), meaning that the risk of this happening again is virtually zero. Hypochondroplasia, is just one of many in a family of bone dysplasias which are caused by the same mutation in the FGFR3 gene. Some examples of other conditions in this family are, achondroplasia (which is the closest to hypochondroplasia but more severe), SADDAN syndrome, and thanatophoric dysplasia. Hypochondroplasia however, is known to be the mildest in this particular series of related conditions. Common features of one with hypochondroplasia are, short arms, short legs, broad, short hands and feet, large head, limited range of motion at the elbows, sway of the lower back, and bowed legs. It is estimated that 1 in every 15,000 to 40,000 newborns are born with hypochondroplasia each year, in the USA alone. This works out to only 0.01% of the population. One site reports that there are approximately 180,000 to 312,000 known live births, to …show more content…
date.
Health Conditions Associated With Hypochondroplasia
GROWTH An individual with hypochondroplasia, will reach a total adult height of 3’10” to 5’5” (118-165cm). The median height for people with this condition is usually 4’8”. Sometimes the diagnosis of this condition can be delayed due to growth being so close to normal, in the first 3 years of life. Parents should pay close attention to the other health conditions associated with this condition, in order to catch the diagnosis early enough so that they can deal with the potential problems to come. Some may choose to use a growth hormone however; this has a very minimal effect, if any.
HEAD GROWTH About 50% of children with hypochondroplasia also have macrocephaly, meaning their head is abnormally large. This condition is diagnosed when the circumference of the child’s head is more than two times the average size for children of their same age, race, sex, and period of gestation. Regular neuroimaging should be done if the growth of the child head accelerates or if signs and symptoms of hydrocephalus (which is caused by the buildup of cerebrospinal fluid) occur. In some more severe cases, ventriculoperitoneal shunting is performed. Signs and symptoms to watch for when determining if one has hydrocephalus are, abnormal gait, urinary incontinence, and dementia.
SEIZURES Seizures are evident in only a small number of hypochondroplasia cases, this being number being near 5-10%. However, in almost all of these cases individuals also have temporal lobe dysgenesis, which is a structural abnormality of the brain. The standard treatments used for individuals with epilepsy can be used by those with hypochondroplasia, for the treatment of seizures.
Health Conditions Associated with Hypochondroplasia (Cont’d)
DEVELOPMENT Near half of individuals with hypochondroplasia are diagnosed with a learning disability, 10-12% of these individuals have a secondary diagnosis of mental retardation.
Special programing and teachers directed to an individual’s specific needs are available for those who require the assistance.
EARS & HEARING Many children with hypochondroplasia (unfortunately it is not known exactly how many at this point in time), will develop middle ear dysfunction. This can be recurrent and persistent and is accompanied by conductive hearing loss. If this is not treated right away it can lead to delays in one’s language and speech. A surgical incision into the eardrum, in order to relieve pressure or drain fluid (also known as myringotomy) can be performed, including tube placement. However, if a child is in need of ventilation tubes, they should be maintained until the age of 8 years.
LIMITED ELBOW EXTENSION The average person has an elbow extension of 150˚, for an individual with hypochondroplasia however, a limitation of 20˚ to 60˚ is common. This effects ones effective reach, making it difficult to perform certain tasks (e.g. for toileting). One with these limitations can use adaptive devices if necessary (e.g. bottom wiper for
toileting).
VARUS DEFORMITY About 10-12% of those with hypochondroplasia, have progressive varus at the knees and the mesial segments of the legs (an oblique displacement of part of the limb, toward the midline). If ones joints become significantly out of position and is accompanied by pain, surgical intervention is needed. Surgical options include the use of 8-plates, epiphysiodesis, and open osteotomies.
Can You Cure Hypochondroplasia
There is no cure for hypochondroplasia however, some symptoms of this condition can be managed. There is however, an experimental treatment to try and increase the final adult height of individuals with this condition. This treatment is “Limb-lengthening therapy”, which is very long, costly, and is accompanied with complications such as; pain, infections, and nerve problems. This procedure can increase the overall height by 12-14” (30.5 to 35.16cm). This treatment is not usually recommended, seeing as it is still in the experimental stages.
Children Living With Hypochondroplasia
Although there is no cure for hypochondroplasia, this is not a bad thing. Individuals born with this condition are just the same as you and I, and it is important that they know this.
Like all children living with visible physical differences, children with hypochondroplasia can have problems at school and socially fitting in. Although we all wish problems of this sort did not exist, they unfortunately do. However, support groups such as, “Little People of America”, can be a great source of guidance for these children and can teach them how to cope and deal with these unfortunate issues. It is especially important that children with hypochondroplasia, or children living with any sort of developmental disability for that matter, not be limited to school activities, so long as they pose no danger. In order for these children to feel good and not feel, “different” (so to speak), they need to interact with other children and engage in social activities.
Conclusion
Hypochondroplasia is not so common but when we look at it as a “family”, including all disorders in the “bone dysplasias” family, it is in fact a lot more common. It is important that we know and understand the problems individuals living with these conditions face, if not to help them, at least to help understand them better. It is hard for anyone in the world who feels “different”, and it is our job to help take those feelings away, having a great understanding of these individuals conditions and other health issues they may be living with, will help us to do that. By reading the “health issues associated with hypochondroplasia” section in my report, you saw that a lot of these conditions can happen to any one of us, not all together of course but, we are still all subject to these complications, this just proving exactly how much we are all alike. Another point worth thinking about is that any one of us could take part in creating the beautiful life of a baby with hypochondroplasia, even if both you and your partner are of average height, this does not exclude you from this occurrence. With that being said, it is important that we educate ourselves not only on this particular condition but to all of those in the “developmental disability” family, you never know if that baby growing inside you will be born with a certain condition so, educate yourself so that you are prepared to care for this new beautiful life you have created.
Work Cited From:
1. http://www.nemours.org/service/medical/skeletaldysplasia/hypochondroplasia.html?tab=about&kidshealth=45743
2. http://www.healthofchildren.com/M/Macrocephaly.html
3. http://emedicine.medscape.com/article/1150924-overview
4. http://ghr.nlm.nih.gov/condition/hypochondroplasia
5. http://www.sickkids.ca/PaediatricLaboratoryMedicine/Laboratories-Services/Molecular-Genetics-Laboratory/Test-Services-Available/Achondroplasia-Hypochondroplasia.html
6. http://www.healthline.com/galecontent/hypochondroplasia
7. http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=9&ved=0CGcQFjAI&url=http%3A%2F%2Fwww.lpaonline.org%2Fassets%2Fdocuments%2FNH%2520Hypochondroplasia1.pdf&ei=2c1NUpvePJL3yAH694HwBQ&usg=AFQjCNHbaBuBy-cULmDY4LJbDUZur2PKaA&bvm=bv.53537100,d.aWc
8. http://health.yahoo.net/galecontent/hypochondroplasia/5
Glossary of Terms
Achondroplasia – A form of disproportionate stature caused by changes in the same gene as hypochondroplasia.
Thanatophoric Dysplasia - A severe skeletal disorder characterized by extremely short limbs and folds of extra skin on the arms and legs.
SADDAN Syndrome - Is a rare disorder of bone growth characterized by skeletal, brain, and skin abnormalities.
Ventriculoperitoneal Shunting - Surgery to treat excess cerebrospinal fluid (CSF) in the brain.
Macrocephaly - An abnormally large head; differs from hydrocephalus because there is no increased intracranial pressure and the overgrowth is symmetrical.
Hydrocephalus - A condition in which fluid accumulates in the brain, typically in young children, enlarging the head and sometimes causing brain damage.
Abnormal Gait - Is a deviation from normal walking (gait).
Urinary Incontinence - Inability to control the flow of urine and involuntary urination
Dementia - A chronic or persistent disorder of the mental processes caused by brain disease or temporal lobe dysgenesis
Myringotomy - Surgical incision into the eardrum, to relieve pressure or drain fluid
Varus Deformity - Weight bearing on outside of foot.
Epiphysiodesis - Staples or 8 plates are placed in the growth plates in the femur near the knee to stop the bone from growing temporarily or permanent
Open Steotomies – Reshaping a bone