Birth defects, also called congenital anomalies, are physical abnormalities that occur before a baby is born. "Congenital" means "present at birth." (See also Introduction to Birth Defects of the Face, Bones, Joints, and Muscles Introduction to Birth Defects of the Face, Bones, Joints, and Muscles Birth defects, also called congenital anomalies, are physical abnormalities that occur before a baby is born. "Congenital" means "present at birth." Birth defects of the face and limbs are fairly... read more .)
Arthrogryposis is a condition in which joints become permanently fixed or "frozen" in position. Frozen joints may be present in more than 300 different disorders, and more than 35 specific genetic disorders (such as spinal muscular atrophy type I Spinal Muscular Atrophies (SMAs) Spinal muscular atrophies are hereditary disorders in which nerve cells that originate in the spinal cord and brain stem degenerate, causing progressive muscle weakness and wasting. The five... read more and trisomy 18 Trisomy 18 Trisomy 18 is a chromosomal disorder caused by an extra chromosome 18 that results in intellectual disability and physical abnormalities. Trisomy 18 caused by an extra chromosome 18. Infants... read more ) have been associated with arthrogryposis multiplex congenita.
Causes of Arthrogryposis Multiplex Congenita
Any condition that impairs or limits the movement of a baby while in the womb can result in arthrogryposis multiplex congenita. Examples include
Limitation of the baby's movement, for example, because the mother's uterus is oddly shaped, she is carrying more than one baby, or the amniotic fluid is insufficient Problems With Amniotic Fluid Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include Too much amniotic... read more
A genetic disorder affecting the baby's ability to move while in the womb, such as muscular dystrophy Introduction to Muscular Dystrophies and Related Disorders Muscular dystrophies are a group of inherited muscle disorders in which one or more genes needed for normal muscle structure and function are defective, leading to muscle weakness of varying... read more or a connective tissue disorder Overview of Connective Tissue Disorders in Children Connective tissue is the tough, often fibrous tissue that binds the body's structures together and provides support and elasticity. Muscles, bones, cartilage, ligaments, and tendons are built... read more
Symptoms of Arthrogryposis Multiplex Congenita
In infants with arthrogryposis multiplex congenita, a number of joints become curved and frozen and consequently cannot bend. The muscles attached to the frozen joints are usually weak and poorly developed. Decreased movement of the baby's muscles and joints while in the womb likely cause the decreased movement of the joints after birth. Sometimes the nerves that would normally move the bones in the affected joints are also impaired. Infants with arthrogryposis may also have dislocated hips, knees, or elbows.
Diagnosis of Arthrogryposis Multiplex Congenita
A doctor's evaluation
Before birth, abnormal limbs may be seen during a routine ultrasound. If abnormal limbs are seen, doctors may do ultrasounds of other parts of the fetus's body or genetic testing on the fetus using chorionic villus sampling Chorionic Villus Sampling Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more or amniocentesis Amniocentesis Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more .
After birth, doctors do a physical examination and note the baby's frozen joints and limbs. A baby who has these birth defects may be evaluated by a geneticist. A geneticist is a doctor who specializes in genetics (the science of genes and how certain qualities or traits are passed from parents to offspring). Genetic testing of a sample of the baby's blood may be done to look for chromosome and gene abnormalities. This testing can help doctors determine whether a specific genetic disorder is the cause and rule out other causes.
Tests of the muscles, such as a muscle biopsy (removal of a sample of muscle for examination) and electromyography Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more (EMG), may be done to help doctors distinguish between various types of arthrogryposis.
Prognosis for Arthrogryposis Multiplex Congenita
Babies born with arthrogryposis typically develop relatively normal intelligence, except when the arthrogryposis is caused by a disorder or syndrome that also affects intelligence.
Doctors seek to establish a specific diagnosis for what has caused the arthrogryposis so that parents know what the prognosis is and can receive genetic counseling.
Many children do remarkably well. About two thirds of affected children are able to walk after treatment.
Treatment of Arthrogryposis Multiplex Congenita
Casts and physical therapy
Placing the baby's limbs in a cast and doing physical therapy Physical Therapy (PT) Physical therapy, a component of rehabilitation, involves exercising and manipulating the body with an emphasis on the back, upper arms, and legs. It can improve joint and muscle function, helping... read more to carefully move and manipulate the stiff joints may improve joint movements.
Surgery may be needed to free the bones from attached tissue in order to have more normal joint movement. Surgically moving a muscle (for example, moving the triceps muscle so that it can flex rather than extend the elbow) may improve function.