Werdnig-Hoffmann syndrome is a severe rare disease which is a subtype of the spinal muscular atrophies (SMAs). SMAs are conditions characterized by nerve cell and motor neuron (nerve cells that transmit signals from the brain or spinal cord to the muscles) degeneration within the lower brainstem and spinal cord, respectively. They are therefore defined as motor neuron diseases.
Around 80 percent of patients with SMA develop the most severe form of the condition; referred to as the topic of the article, Werdnig-Hoffman syndrome. Males and females are affected equally with the condition, with the prevalence of all the SMAs estimated to be at a rate of up to nearly 8 cases per 100,000 births.
The cause of SMA is due to mutation in the survival motor neuron 1and 2 (SMN1and 2) genes. When this occurs, abnormal proteins are produced and this results in motor neurons not being able to function properly. The condition is an autosomal recessive one, which means that a defective gene from both parents needs to be passed onto the child in order to develop SMA. If only one defective gene is passed, then the child will be a carrier of the condition and will not develop any signs and symptoms of SMA. The specific underlying cause of Werdnig-Hoffmann syndrome though is not known.
Werdnig-Hoffman syndrome is a devastating disease for families due to the poor prognosis of the condition, and for the fact that infants are affected where they don’t survive for very many years.
The clinical picture
The early signs and symptoms of Werdnig-Hoffmann syndrome vary among affected individuals and include the following:
- Generalized muscle weakness in infants before 6 months of age.
- Decreased muscle tone resulting in the child seeming floppy.
- Absence of tendon reflexes.
- Abnormally flexible joints.
- Twitching movements of the tongue.
- The lower limbs of the affected child seem to resemble that of a frog with the hips moved apart and the knees flexed.
- The child also tends to have an alert appearance on their face, but facial muscles are spared at this time.
The mental development of the child is fine, but they don’t gain head control, they can’t turn over to their sides or roll over, and are unable to sit or stand. Other issues that may develop include difficulties in swallowing and breathing, and this can result in the development of respiratory infections and other life-threatening situations within the first few months or years of life, such as choking due to inhalation of foods or fluids.
Diagnosing Werdnig-Hoffmann syndrome
The diagnosis of SMA is suspected on the history given by the parents or caregivers of the patient, and on the clinical findings made on examination of the child. The confirmation of the diagnosis will be made on genetic testing where the defects will be demonstrated on the SMN1 and 2 genes.
The confirmation of Werdnig-Hoffman syndrome is then made on the diagnosis of SMA together with the specific severe clinical signs and symptoms of the condition, as already mentioned.
Unfortunately, there is no cure for infants diagnosed with Werdnig-Hoffman syndrome, and the prognosis of the affected individual is poor with most of these patients dying before 2 years of age. This does though depend on the degree of the patient’s respiratory function, so there are cases where children have lived past 2 years of age.
The management of infants with Werdnig-Hoffman syndrome though will depend on the specific symptoms they present with. A multi-disciplinary approach is incorporated in these patients as they require many specialists to help manage their specific systemic issues.
Patients with feeding difficulties may require having a feeding tube inserted directly into their stomach through a surgical opening made in the abdomen (gastrostomy).
Physical and occupational therapy is utilized to help reduce the risk of contractures (stiffness) of the joints of the limbs on these patients. If indicated, surgery to loosen already developed contractures and to reduce complications, caused by issues such as scoliosis of the back, may be performed if the benefits outweigh the risks.
Affected patients’ respiratory functions gradually decline with this condition. Therefore, treatment options for these infants may range from no respiratory support, to using non-invasive therapies (such as intermittent positive pressure ventilation), or having to make use of more longer-term invasive procedures such as making a surgical incision in the trachea and inserting a tube to facilitate breathing (tracheostomy).
These may become difficult decisions to make because watching these children struggle to breathe and being hooked up to tubes and machines are heart-breaking situations for parents and caregivers. Trauma and psychological counselling also needs to be made available to these parents and caregivers, since they are ultimately responsible for the decision that needs to be made to stop all forms of therapy when it comes to the point where further management won’t maintain an adequate quality of life for the infant.
Jaime Gooden and her husband have shared their story about the diagnosis of Werdnig-Hoffmann syndrome in their daughter, Nora. The Goodens recalled the time when they became pregnant with Nora and envisioned all her potential future memories such as graduating and getting married. They mention how when she was born, she did all the normal things newborn babies do, and how she had passed all the screening tests and examinations without there being any issues.
The Goodens though realised that around the time Nora was 2 months old, something was not right when she was examined by her pediatrician. The tone in her legs was underdeveloped, but they were told to continue with Nora’s daily tummy routine to help improve her muscle tone. When compared to other children though, Nora’s legs were not moving. At her 4 month visit though, she was suspected as having cerebral palsy and referred to a neurologist. This was an extremely difficult time for the Goodens, especially not knowing what was going on and what would happen next.
The Goodens remember the examination of their daughter where the specialist found no deep tendon reflexes, and overhearing doctors mentioning SMA as a possible diagnosis. They had waited three long and agonizing weeks for the test results to come back, and the results confirmed that Nora indeed had Werdnig-Hoffmann syndrome.
Up until now, Nora has had numerous respiratory infections due to aspirating food and fluids into her airways. Her parents carry a suction tube to help remove saliva from her mouth because she struggles to swallow this fluid, too.
The Goodens spent, and still spend, every moment with Nora who has recently graduated from kindergarten. They have accepted that their precious girl will never sit, never walk, and may die from this condition within a few years. As the years progress, so will the disease, and this will cause Nora to struggle more with eating and breathing.
The Gooden’s mission now is to continue providing the care Nora needs, spending as much time as they can with their daughter, and increasing awareness for SMA, especially Werdnig-Hoffmann syndrome. Nora’s parents share their story with others in order to increase awareness of this disease, and to offer support to those families who are dealing with a similar scenario to theirs.