About DESSH Syndrome
DeSanto-Shinawi Syndrome is a rare neurodevelopmental genetic disease and is often referred to as 'DESSH' and is sometimes called WAC syndrome. It is an autosomal dominant condition caused by pathogenic variants of the WAC gene. DESSH is diagnosed using a test called whole exome sequencing and has only been identified in about 200 people worldwide. DESSH was first identified in 2015 in a study of 6 patients. Patients exhibit a variable degree of developmental delay, intellectual disability, hypotonia, ocular abnormalities, gastrointestinal abnormalities, epilepsy, behavioral difficulties, and recognizable facial differences. To download a PDF resource about DESSH, click here.
Symptoms and Diagnosis
Low muscle tone (hypotonia) particularly affecting the mouth and throat area, resulting in poor articulation (dysarthria) and swallowing difficulties.
Behavioral problems including autism spectrum disorder, ADHD, sleep disorders and anxiety.
Characteristic facial appearance, typified by a square-shaped head; 4 deep-set, long eyes; a wide mouth; a broad chin; and minor ear anomalies.
These features are not observed in all individuals and are not specific to WAC syndrome.
Almost all children experience a delay in meeting their motor development milestones, such as rolling, crawling and walking. The age at which children achieve independent walking ranges from 12 to 36 months.
The majority of children with WAC syndrome have a mild intellectual disability (ID) (a moderate to severe ID was observed in fewer than one in five children). Reported IQ values range from 44 to 98. Extensive psychocognitive evaluation of some of the children revealed relative difficulties in non-verbal skills and in sustaining attention and maintaining focus. Basic language skills and verbal memory skills are areas of relative strength.
A variety of behavioral problems are known to be part of WAC syndrome including ADHD, autism, anxiety, sleep disturbances and aggression.
A delay in language development is observed in almost all children with WAC syndrome. The age at which children speak their first words ranges from 14 months to five years. Only a small minority of children remain non-verbal. Due to low muscle tone around the mouth and throat, some children have problems with articulation (dysarthria).
FINE MOTOR SKILLS
Development of hand use and hand-eye coordination are impaired in children with WAC syndrome. Children usually benefit from physical therapy and occupational therapy.
Babies with DESSH are usually born at a normal birth weight and continue to grow at the expected rate. Some children have problems maintaining their weight within a normal range, while some instances of children who are overweight have been reported.
LOW MUSCLE TONE
Low muscle tone (hypotonia) is obvious in around half to three quarters of children and may persist throughout childhood. The condition is particularly severe around the mouth and throat area, resulting in poor pronunciation and swallowing difficulties.
Feeding difficulties in the neonatal period have been reported, including gastroesophageal reflux disease (GERD). For some babies who are more severely affected, temporary feeding by nasogastric tube may be necessary.
Constipation has been observed in several children with DESSH.
Several children are known to have epilepsy. An EEG should be undertaken if seizures are suspected. Cases of 7 tonic-clonic seizures, absence episodes, and febrile convulsions have been reported.
EYES + EYESIGHT ISSUES
A wide range of eye and eyesight problems have been reported. These include but are not limited to: unexplained reduced vision or cortical visual impairment (an inability of the brain to interpret what the eyes can see), long -sightedness and strabismus.
Recurrent respiratory infections have been reported in children in the medical literature, most frequently in childhood. Cases of asthma and an abnormal breathing pattern have also been observed.
Some children have non-specific anomalies of the brain, of which an enlargement of the fluid-filled ventricles in the brain is the most frequently reported. This may interfere with the body's ability to drain cerebrospinal fluid from the brain resulting in hydrocephalus - a build-up of fluid within the brain. Ventriculomegaly and prominence/enlargement of subarachnoid spaces have each been reported on a few occasions. Other findings include asymmetry of the hemispheres of the brain.
In some children, excessive hairiness on parts of the body where normally hair is absent or minimal has been observed.
OTHER BIRTH ANOMALIES
A wide range of congenital anomalies have been described, but none of them have been found recurrently in children with DESSH. Reports include: kidney anomalies; occlusion of the tear duct; an abnormality of the windpipe (trachea); hip dysplasia; hearing loss; anomalies of the feet and hands; hypogammaglobulinemia associated with recurrent infections; leukopenia and thrombocytopenia; and diaphragmatic hernia (the sheet of muscle between the abdomen and the chest is not complete, allowing organs from the abdomen to be displaced into the chest). Children with 10p12p11 deletions that include WAC as well as neighbouring genes tend to have more medical concerns than children with changes confined to the WAC gene alone. Heart abnormalities in particular seem to be more frequently observed in children with 10p12p11 deletions.
Information provided by rarechromo.org
As DeSanto-Shinawi Syndrome is studied and characterized, we grow closer to dedicated treatments that target the cause of its manifestations. Collaboration between patients and researchers is the key to understanding DESSH and subsequently discovering targeted treatments. Until then, it is important to treat its symptoms.
Occupational therapy, physical therapy, speech therapy including PROMPT therapy, behavioral therapy including ABA and PCIT training methods have successfully improved symptoms.
Specialists in neurology, ophthalmology, genetics, allergy and immunology, gastroenterology, pulmonology, and psychology may help depending on individual symptoms. A developmental pediatrician and the child study team at schools are important resources for babies, toddlers, and school age children.
A variety of medications may be used to treat DESSH symptoms. Atypical antipsychotics for aggression include Risperdal and Abilify, and both are FDA approved autism treatments. Anxiety and mood disorders can be treated with SSRIs. Stimulants, clonidine, guanfacine, and buproprion may improve symptoms of ADHD. Finally, anti-seizure medications that also modulate glutamate/GABA balance can help like Topomax. All medication should be administered under a doctor's care.
Did I cause my child to have DESSH?
Most cases of DESSH syndrome are not inherited and affected people typically have no history of the disorder in their family. The condition can be passed down and is inherited in an autosomal dominant manner. DESSH occurs when one of a person’s two copies of the WAC gene is deleted or changed. Genes are made of a complex chemical called DNA and make up the “instruction manual” that tells the body how to grow, develop and function. Genes are arranged in organized structures called chromosomes. There are 23 pairs of chromosomes and we inherit one half of each pair from each parent, making a total of 46 chromosomes. The WAC gene is on chromosome 10 and codes for a protein that plays a role in different cellular and DNA processes, including processes important for brain development. Chromosome rearrangements affect children from all parts of the world and from all types of background. They also happen naturally in plants and animals. There is nothing that either parent did before, during or after pregnancy that caused the change. It is no one’s fault.
Can it happen again?
Provided that neither parent is found to carry the same WAC gene mutation as their child, the chance of having another child with the same genetic change would be considered extremely low. Empirically, this risk would be considered less than 1%. The reason why there is some residual risk of recurrence is due to a rare phenomenon called ‘gonadal mosaicism’. This is when a parent carries a genetic change, but it is limited to a small cluster of their egg or sperm cells. The genetic change would not, therefore, be detected in this parent’s blood test. For specific advice about the chance of this happening again, it would be sensible to speak to a clinical geneticist or genetic counsellor. One presumed case of WAC syndrome as a result of gonadal mosaicism has been reported.
Information provided by rarechromo.org