Description, Causes and Risk Factors:
Marden-Walker syndrome is a rare congenital connective tissue disorder. Over 75% of children with MWS have bleharophimosis, small mouth, micrognathia, kyphosis/scoliosis, radioulnar synostose and multiple contractures.
Etiology of MWS is probably heterogeneous. Initially described as a syndrome, this condition is more likely to be the phenotypic expression of various hetregeneous disease and belong to the group II in the classification of arthrogryposis. The report of two affected sibs, with a female presenting a typical Marden-Walker syndrome and a normocephalic male fetus with severe distal arthrogryposis without facial dysmorphism, sugest that Marden-Walker syndrome and isolated distal arthrogryposis may be variable manifestation of the same entity. Unknown congenital myopathy has been suspected to underlie MWS due to muscular involvement, but extensive evaluation of the neuromuscular system failed to identify a primary myopathy in patients with MWS.
Marden-Walker syndrome is inherited as an autosomal recessive trait. The exact genetic malfunction is not yet established but some clinicians believe a single gene defect may be responsible.
Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22, and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated "p" and a long arm designated "q". Chromosomes are further subdivided into many bands that are numbered. For example, "chromosome 11p13" refers to band 13 on the short arm of chromosome 11. The numbered bands specify the location of the thousands of genes that are present on each chromosome.
Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.
Recessive genetic disorders occur when an individual inherits the same abnormal gene for the same trait from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the defective gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. The risk is the same for males and females.
All individuals carry a few abnormal genes. Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.
Since 1966, about 30 cases of Marden-Walker Syndrome have been reported.
Disease course is always characterized by failure to thrive and psychomotor retardation. Mental retardation remains severe, whereas contractures are not progressive and decreases with advancing age and physiotherapy. Nevertheless, the natural history of MWS is not well-known. Many patients died in infancy and clinical follow-up has only been reported in few surviving adult patients. Moreover, diagnosis may be more difficult to establish in adult patients, blepharophimosis, contractures, growth retardation and developmental delay persist, whereas minor face anomalies are less noticeable as the patient grows older. Behavior changes from kindness in childhood to restlessness, hyperactivity, and aggressiveness in adolescence.
The differential diagnosis is relatively limited encompassing 2 other symptoms: Freeman-Sheldon syndrome and Schwartz Jampel syndrome, which share some features of MWS, although they are usually both associated with normal mental development. Moreover, Freeman-Sheldon is characterized by the absence of joint contractures, which are progressive and not present at birth in Schwartz Jampel syndrome. Many children of the series described with the diagnosis of Pseudo trisomy 18 match diagnostic criteria suggested by Williams and are probably MWS. Presence of some symptoms such as myotomy should rule out MWS.
No specific therapies are available. Treatment involves supportive care, including use of dietary therapy and anticonvulsant drugs, when necessary. Contractures may also benefit from physical therapy.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
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