Larsen Syndrome

What is Larsen Syndrome?

Larsen syndrome is an uncommon ailment that hinders the normal development of bones in the human body. The condition is characterized by an abnormality in the growth and expansion of the body framework. However, the extent of any one given infection varies depending on the body of the subject.

The effects vary from one individual to another even if the affected share a common blood line. Infants born with the complication have their lower limbs characterized by clubfeet. Ideally, the legs are bent inwards as well as the disarticulation of the body joints; knees, hips and elbow. The syndrome causes small extensions of bones at the tips of thumbs and fingers.

larsen syndrome

Hypermobility is also associated with the illness. Hypermobility is the increased movement of the joint hinges. Additionally, the condition brings about a small physique and the bending of the spine; kyphosis. Such symptoms are responsible for the feeble lower limbs. Other than the limbs, the disease is liable for characteristics such as:

  • Characteristic prominent forehead
  • Wide set of eyes
  • Cleft palace
  • Flattening of the space between the nose and the central face; midface hypoplasia
  • Hearing loss due to the overgrowth of ossicles in the ears.
  • Respiratory hitches among some patients. This is as a result of a weak respiratory system that prevents the smooth passage of air and occasional respiratory tract infections.

Signs & Symptoms

  • Widely spaced eyes
  • Curvature in the spinal cord
  • Feet that are curved upwards and inwards; clubfoot.
  • Blunt and compact thumbs
  • Hypermobility of joints
  • Heart illnesses
  • Respiratory tract defects

Despite the wide range of symptoms of the disease, its symptoms are expressed differently among diverse subjects. Even if the affected belong to the same family, the effects will be individualized, with each patient complaining of a different experience. Recurring mutations are to blame for the many infections that target members of a certain family.

These mutations cause digress concerns among the members of the affected family. This can either consist of a cleft palate and prominent face, while another could have limited facial deformities but the major characteristic be stunted physical development. Such effects can be attributed to the shortening of phalanges and the protrusion of extra bones on the tips of fingers and thumbs.

Larsen syndrome faces photos

A classic case of the infection is characterized with abnormalities in the body frame features. This is expressed by weak and moving joints such that the ball and socket is not fixed as it should be, instead it allows sideways movements.

Majority of the signs and symptoms of Larsen syndrome reveal themselves immediately after birth. Dislocation of the major joints in the body is common, with the hip and knees being the most affected. Majority of these infections are also characterized by clubfoot. Additionally, you could have supernumerary carpal and tarsal bones.

A considerable amount of the patients suffering from the condition have issues with their spinal cord. Statistics show that over 80% of the affected have curved backbones either; frontal, back or at the connection to the neck. Individuals with the Larsen Syndrome as well as hypoplasia are in grave danger of contracting cervical cord damage which in advanced stages brings about paralysis. However, it is very rare for such an ailment to be reported.

In spite of the vast effects of the disease, it is very sporadic to find patients with an abnormality of the windpipe. This is due to the tempering of the trachea making the intake and absorption of air difficult. The condition is known as tracheomalacia.

What causes Larsen Syndrome?

Larsen syndrome is caused by alterations of the FLNB gene. The gene is responsible for coding information vital for the conversion of the protein called Filamin B. The protein is liable for the formation of a cytoskeleton that binds together cells and allow their form and mobility.

Larsen syndrome genetics chromosomal defect causes

The cytoskeleton is made even stronger by the combining with protein actin. This is responsible for the frame work of filaments in the system. This also works in tandem with other proteins in the cell to perform various crucial cell functions. The most crucial role it plays is cell signaling. This refers to the tuning of the cell components to determine the manner and nature of growth of the cytoskeleton as growth and development proceeds.

Filamin B is responsible for the formation of the skeleton before an infant is born. Its presence is in the membranes of cartilage forming cells. The cartilages are often strong and rough tissues that are liable for the development of the skeletal system in the early stages of development. Later on, the cartilage is gradually converted to bone in the process of ossification. However, the development of the cartilage is restricted on those cartilages whose purpose is covering crucial body organs such as the nose, breathing system and the outer eyes.

Testing and Diagnosis

The diagnostic procedure kicks off with a thorough insight into the medical history of the child as well as physical inspection to check for any symptom that indicates presence of the disease. The following tests are done to verify the entry of disease pathogens in the body.

  • X-rays- Look into images of bones.
  • CT scans- Utilizes X-rays and computers to derive sliced images of body parts.
  • Magnetic resonance imaging- Utilizes magnetic beams to produce detailed images of internal organs.
  • Blood tests


As the ailment affects various body organs and systems, it makes it hard to roll out the ideal procedure to counter the effects of the disease. However, in most cases, all that is needed is constant and thorough monitoring of the organs. It is only in extreme conditions that surgery is incorporated into the procedure to counter specific effects of the condition.


The syndrome is passed on to another family member in an autosomal dominant manner. This means that only one copy of the altered gen is enough to warrant the setting in of the signs and symptoms.


Upon critical care of infected children, young ones can surpass childhood into maturity while living normally with the disease. Also, in case of excruciating pain in the joints, hip or knee, a replacement ought to be done to correct the ailment.


Larsen syndrome is a serious ailment, whose effects on the body cannot be underestimated. However, proper and prompt care and follow up will ensure that the children have and live a normal life despite the minor challenges that never lack.


  1. Clayton-Smith J, Donnai D. A further patient with the lethal type of Larsen syndrome. J Med Genet. 1988;25:499–500. [PMC free article] [PubMed]
  2. Coêlho KE, Ramos ES, Felix TM, Martelli L, de Pina-Neto JM, Niikawa N. Three new cases of spondylocarpotarsal synostosis syndrome: clinical and radiographic studies. Am J Med Genet. 1998;77:12–5. [PubMed]
  3. Critchley LA, Chan L. General anaesthesia in a child with Larsen syndrome. Anaesth Intensive Care. 2003;31:217–20. [PubMed]

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