What is Arthrogryposis Multiplex Congenita?
Arthrogryposis or Arthrogryposis Multiplex Congenita (AMC) is a condition that causes tightening of the muscles, tendons and joints, making them stiff and difficult to move. It is a congenital defect that causes more than one contracture or permanent tightening of joints/muscles and usually happens as a part of other disorders or syndromes.
Arthrogryposis Multiplex Congenita Causes
Arthrogryposis cause is not clearly known but scientists believe it to be caused by genetic mutations and disorders, may not be recurrent in the family so not necessarily hereditary. Some of the plausible causes of arthrogryposis are:
Lack of fetal movement inutero: Lack or low fetal mobility in womb as a result of low amniotic fluid, odd shaped uterus or other baby around (twin) could cause tissue to grow around joints not used.
Maternal trauma or infections during pregnancy.
In mothers with multiple sclerosis
Genetic disorders like muscular dystrophy
Mutations to the TTN gene (titinopathy)
Neurological disorders affecting the brain and spinal cord
Issues with connective tissue, central nervous system and or neuromuscular system in the baby that cause stiff joints and muscles.
Related: What is Congenital Titinopathy?
What is Recessive Titinopathy?
Types of Arthrogryposis Multiplex Congenita
Based on the muscles, joints and body parts it affects, arthrogryposis is categoriezed in four types
Amyoplasia - This is the most common type of arthrogryposis affecting the muscles and joints of both the arms and legs with reduced range of motion in joints, poorly developed muscles with possible deformities.
Distal Arthrogryposis - It affects only few joints of the hands and the feet with limited range of motion to an extent.
Syndromic Arthrogryposis - Along with affecting the muscles and joints, it affects the internal organs as well causing breathing difficulties, speech or developmental delays and feeding difficulties
Classic Arthrogryposis - It affects the hands, wrist, elbows, shoulders, hip, knees and feet, based on the severity it could affect all the joints and muscles in the body including the back and jaw.
Arthrogryposis Multiplex Congenita Symptoms
The symptoms vary greatly from one child to another based on the severity, type and the parts of the bosy it affects. Some of the commonly seen symptoms that vary across patients are
Limited or no movement in the joints
Overlapping joints
Joints stuck in unusual positions
Delayed growth and milestones
Muscle weakness
Thin bony body structure
Stiff, weak, or missing muscles
Small tube like limbs
Long fragile and slender bones in the limbs
Webbing of soft tissue over joints preventing easy movement
In severe cases can impact the respiratory and cardiovascular functioning as well.
Arthrogryposis Multiplex Congenita Diagnosis
Doctors could diagnose arthrogryposis in pregnant women during the second trimester scans when issues with the limbs and movement are more pronounced than before. They may also recommend further testing using amniocentesis or chorionic villus sampling if dectected earlier in pregnancy.
Once the baby is born, doctors do various tests to assess the degree of issues.
Genome Sequencing - To identify altered genes
Muscle Biopsy - To testa small piece of the muscles, check for anomalies and genetic conditions
Microarray - Assess and analyze multiple thousands of genes at once
Blood Tests - Checks for any hromosomal abnormalities
Electromyography - Checks the electrical activity in the muscles
Arthrogryposis Multiplex Congenita Treatment
The dotor and specialists in this field will customize a treatment to suit your childs need based on the type and severity of the condition. The commonly used methods include.
Physical Therapy -Includes various techniques (exercises, stretches, heat/cold packs), devices and methods to improve mobility.
Joint Manipulation - Quick small thrusts to the joint to ease pain and increase mobility
Surgery - Even though not commonly done, could help bring back mobility in knees, wrists, ankels, elbows and hip. The surgeon will remove the tissue preventing the movement and will correct any anomalies.
Casts and Braces - To keep joints in place and further correct and repair joint damage.
Long Term Prognosis of Arthrogryposis Multiplex Congenita
Arthrogryposis is nonprogressive so the symptoms may not get worse but the underlying condition causing it could make it worse so talk to your doctor to understand your child's type and condition in detail.
Long term effects vary based on severity and underlying conditions, but most children with arthrogryposis have normal or above average cognitive abilities. They respond well to physical therapy and to treatments that help them lead a fairly normal and independent life.