Apert Syndrome – A Genetic Disorder Of the Skull, Fingers & Toes!
Recently one of my close friends gave birth to a beautiful baby girl. When our friends group got the news, we were overwhelmed with joy as she was the first to embrace motherhood among us. We all were very excited to catch a glimpse and hold the little one in our arms. But when we reached the hospital, the atmosphere was nowhere matching with the adjectives of ‘elation’, ‘delight’ and ‘jubilant’ as it should be. With gasped breaths, hoping everything to be fine we took slow steps towards our friend’s bed where she was sleeping with her mother sitting on her side holding the little one. We all approached the baby and some abnormality was staring at us from the baby’s head, fingers and toes. Just then the doctor had come to explain the baby’s condition which according to him was a rare genetic disorder named Apert Syndrome.
After gathering as much information as I could from the doctor and comforting my friend, I left the hospital. After reaching home, I started collecting more information about the syndrome and here’s what I found about it.
- It was named after the French Physician E. Apert who described it for the first time in the year 1906.
- 1 in 65,000 newborns has the syndrome which approximates to 15.5 in 1,000,000 live births.
What is it?
Apert Syndrome or Acrocephalosyndactyly is characterized by the fusion of skull bones prematurely during the embryonic development of fetus inside the uterus. This in turn affects the shape of head, midface, hands and feet.
- The skull grows abnormally due to premature fusion of skull bones, giving the appearance of an irregularly shaped head.
- The midface or the area from the centre of the eye-socket to the upper jaw appears sunken.
- 3 or more Fingers and toes are fused together giving a webbed appearance.
Craniosynostosis – The normal skull consists of several loosely connected plates which grow together gradually to form the adult skull. Unlike this normal condition, in a child with apert syndrome these plates get fused earlier than the actual stage causing restricted brain growth and increased pressure on the brain leading to abnormal shape of the head. This condition is referred to as craniosynostosis.
Syndactyly – It is nothing but the fusion of toes and fingers. Starting with a minimum of 3 digits, the fusion of all fingers and/or toes is also seen in most of the cases. Soft tissue between the first, middle and ring finger is usually fused, but fusion of the bones is also a common symptom. In some children, the thumb may fuse into the hand. Because the fusion progresses with the child’s growth, flexibility in moving the hands and feet decreases gradually.
- Webbing or severe fusion of the 2nd, 3rd and 4th fingers resulting in ‘mitten hands.’
- Bulging or very prominent widely set eyes.
- Affected individuals have a short stature.
- Limb or skeletal abnormalities.
- Hypoplasia or retrusion – The upper and lower thirds of the face grow normally as the skull grows, but the middle third of the face grows at a slow rate leading to a more prominent retrusion over a period of time.
- Patches of hair seem to be missing in the eyebrows.
- Shallow eye sockets that may cause problems in eye vision.
- Fusion of the cervical or neck vertebrae (bones that make up the spine) giving a short-neck appearance.
- Short nose with bulbous (bulb-like) tip, low-set ears, very high and prominent forehead.
- Visible underdevelopment of the midface.
- Large or late closing soft spot on the baby’s skull.
- Delayed dentition and crowded upper teeth.
Some other symptoms
- Hearing loss.
- Very frequent ear infections which may be due to an opening in the roof of the mouth.
- Severe acne which is a result of an abnormally oily skin.
- Severely underdeveloped upper jaw leading to dental problems such as crowded teeth.
- Impairment of cognitive abilities ranging from moderate to severe intellectual disability.
- Hyperhidrosis or heavy sweating.
Genetics of Apert Syndrome
Mutations (permanent changes in the DNA) in FGFR2 (fibroblast growth factor receptor 2) gene are responsible for this condition. This gene produces FGFR2 protein, whose function is to signal immature cells to transform into bone cells during the developmental stages of the fetus. Due to a mutation in the gene, the protein function is altered resulting in prolonged signaling which in turn enables the premature fusion of the skull bones.
As mentioned earlier, this syndrome is a genetically inherited disorder, running in families and passed on to the next generations. The syndrome is inherited in an autosomal dominant pattern meaning the altered gene from one parent is sufficient for the development of this syndrome in the child. In other words, one copy of the mutated gene in each cell is enough to cause the condition.
People with no family history of the syndrome may also develop it.
Apert & Other Syndromes
Craniosynostosis which leads to the head and face appearance as mentioned above is common in some other syndromes. But apert differs from these in the presence of syndactyly which is absent in them. Some of these syndromes include: Pfeiffer syndrome, Carpenter syndrome, Saethre-Chotzen syndrome and Crouzon disease.
Diagnosis & Treatment of Apert Syndrome
3 diagnostic tests usually confirm the diagnosis. These include:
- Hand and/or foot X-ray – To determine the extant of webbing and associated bone problems.
- Skull X-ray – To confirm the diagnosis of craniosynostosis.
- Genetic Tests – To confirm mutations in FGFR 2 gene. This confirms the diagnosis of the syndrome.
Treatment usually begins at birth soon after diagnosing the condition and is treated in a multi-disciplinary way meaning the expertise of specialists in different medical areas is required. The team requires a craniofacial (skull and face) surgeon, an ENT specialist, a neurosurgeon, an ophthalmologist, an audiologist, a psychologist, an orthodontist, an oral surgeon, a developmental pediatrician, an oromaxillofacial surgeon, a physical and occupational therapy specialist and a speech pathologist to a name a few.
- Retrusion can be corrected using a surgical procedure called LeFort III. In this procedure, the facial bones from the mid eye to the upper jaw region are detached. This step is followed by spacing the area with bone grafts to give a proper alignment to the region.
- Syndactyly can also be surgically corrected, but is usually recommended in cases where the functioning of the limbs is severely affected. For example: if syndactyly is affecting a person’s ability to walk then surgical intervention is suggested.
- Once the diagnosis is confirmed, possible hearing problems should be suspected and treated accordingly. Hearing tests should be performed on a regular basis as the child grows into adulthood.
- Nasal surgery may be required to correct the excessively flattened nasal bridge and to reduce the bulb-like appearance of the tip of the nose.
- Crowded teeth can be corrected which may involve the extraction of some abnormally placed and obstructing teeth to prevent gum infections and other complications.
After reading the implications of this syndrome, you might be wondering if there’s a way to prevent it. Yes, there is indeed! Make sure to advise your near and dear ones who have a family member with this syndrome to undergo genetic counseling before planning to have a baby.