Ashley's form of dwarfism Sept 2007

Ashley’s form of Dwarfism Sept 2007

Since a lot of folks out there are not familiar with dwarfism, here is a little something about the specific type that Ashley has:

Achondroplasia is the most common form of short-limb dwarfism. It occurs in approximately 1 in 26,000 to 1 in 40,000 births. The characteristic features of achondroplasia are apparent at birth. These include typical facial features, disproportionate short stature, and rhizomelic (the proximal ends of the limbs) shortening, depressed nasal bridge, trident fingers, and differences in ossification of the spine.

Diagnosis of achondroplasia is made by physical exam and skeletal x-rays. Most individuals have normal intelligence, in not higher than "average height" people. Infants and children often have motor delays but cognitive delays are not present. A special infant developmental chart has been made for children with achondroplasia. Final adult height is in the range of 4 feet. Special achondroplasia growth curves have also been made. These should be used by the child's pediatrician to monitor growth and development.

The facial features include a large head with a prominent forehead. The midface is often small with a flat nasal bridge and narrow nasal passages. In infancy and childhood, middle ear infections often occur because of the small nasal passages and Eustachian tube dysfunction. If the ear infections are left untreated, hearing loss can occur. "Ear tubes" are probably indicated for a child with multiple ear infections. The jaw appears to be prominent. Occasionally dental crowding can occur since the jaw is small.

Respiratory problems can occur in infants and children. Airway obstruction can be "central" in origin (due to foramen magnum compression) or "obstructive" in origin (due to narrowed nasal passages). Symptoms of airway obstruction include snoring, sleeping with the neck in a hyperextended position, or apnea. A sleep study is done if these symptoms exist to determine the cause of the airway obstruction. Treatment depends on the type of obstruction. I f central obstruction is present, a foramen magnum decompression is performed (see below). If obstructive airway obstruction is present, therapy can include tonsillectomy, adenoidectomy, or tracheostomy placement.

The limbs have rhizomelic shortening. The legs are straight in infancy but when a child starts walking, they can develop a valgus (knock-knee) position. As the child continues to walk, the legs assume a varus (bowleg) appearance. "Bowlegs occur because the outer bones of the legs are longer than the inner bones. Occasionally, children have these leg curvatures corrected. The fingers and toes are short and in a "trident" position (space between the 3rd and 4th fingers.)

Infants have a thoracolumbar kyphosis in the sitting position. Since infants with achondroplasia often have reduced tone, it is recommended that they not be placed in umbrella-type strollers, jumpers, or swings that do not provide good back support since these devices may lead to the development of a gibbus or hump in the back. As the child begins to walk, the kyphosis disappears and the back assumes a lordotic posture. If a child is delayed in walking, the spine should be monitored closely for signs of gibbus formation.

Neurologic complications can occur in achondroplasia. In infancy, hydrocephalus (water on the brain)can develop. Infants should be monitored monthly with measurements of their head circumference to detest a rapidly enlarging head size that can indicate hydrocephalus. The child's pediatrician should have a copy of the head circumference curves for children with achondroplasia. Radiologic studies are indicated if the head circumference increases disproportionately or if symptoms of hydrocephalus develop. Common radiologic procedures include head ultrasound, CT scan, or MRI of the head. If intervention is necessary, a ventriculoperitoneal (VP)-shunt is placed to relieve the excess pressure.

Infants should also be monitored for foramen magnum compression. The foramen magnum is the opening at the base of the skull through which the brainstem and cervical spinal cord exit. Individuals with achondroplasia have narrowed foramen magnums that can then compress the brain stem and spinal cord. Symptoms of narrowing include apnea (cessation of breathing) and cervical myelopathy. CT-scans and MRI scans are done to examine the size of the foramen magnum.(space in your back of neck that spinal cord goes through) If a child is having symptoms, a neurosurgical procedure called foramen magnum decompression is done to enlarge the foramen magnum and alleviate further symptoms. Adolescents and adults are at risk of developing lumbosacral spinal stenosis. The lumbar spinal cord or nerve roots become compressed producing neurologic symptoms. Initial symptoms include weakness, tingling, and pain of the legs. Often the pain is alleviated by assuming a squatting position. As the condition worsens, pain in the low back or buttocks occurs. Diagnosis is made by a neurologic exam, SERs (somatic evoked responses), and CT or MRI scans. Treatment is a neurosurgical procedure called a lumbar laminectomy.

Achondroplasia is an autosomal dominant condition (see the genetics section for further details). This means that a person with achondroplasia has a 1 in 2 or 50% chance of having children with achondroplasia. However, approximately 75% of individuals with achondroplasia are born to parents of average size. In these cases, achondroplasia is due to a new mutation or genetic change. The gene for achondroplasia has been found. It is called fibroblast growth factor receptor 3 (FGFR3). Often, two individuals with achondroplasia have children. These couples are at risk of having a child with 2 copies of the changed gene or double homozygosity. Infants with homozygous achondroplasia are either stillborn or die shortly after birth. Couples at risk often have prenatal diagnosis via serial ultrasounds. A DNA test is now also available to detect double homozygosity.

Ashley has the normal things that most achondroplastic infants have. She holds her head back to breath better. I get a lot of looks from people when we're out because she looks like a newborn and I'm just letting her head hang. In actuallity, she is pushing her head back , which strangers figure out when the come up to me and put thier hands under her head as if to lift it. People always ask, "is that comfortable for her"

She is also starting to develop kyphosis, and needs to see a specialist ever 6 months until she is 3 ys old. We measure her head circumference every couple weeks and send the results to the neurologist who keeps tabs on how quick her head is growing to watch out for hydrocephalus. We have has her checked for siezures as well as hydrocephalus, which so far, she has no signs of.

Her social skills are right on target for other kids her age, except for the motor skills, which is normal for her to have delayed development. She is the perfect little girl, with a beautiful demeanor, always smiling and content.