November 23, 2017

How the over production of skin cells leads to a lifetime of scrubbing

Mary and Dela were excited about welcoming their first baby. But first they had to get through nine months of first time experiences. The first sound of the heartbeat, the first scan, that first kick and the first sign of a contraction. After the anticipation, the time had finally come to welcome their beautiful baby Felicity into the world. With one last push, out came Felicity with her first cry. She was special from the time she was born. Everyone seemed to be fussing over her. They were told she had to be examined and in a short moment she was taken away. Mary couldn’t wait to hold her baby in her arms and Dela was equally overjoyed. When Felicity was eventually brought back to them, the news that accompanied her arrival would change their family life forever; “Felicity has a condition called Ichthyosis, a rare genetic condition that affects about 1 in 250 babies which leads to over production of skin cells and there’s no cure”. The term Ichthyosis (pronounced Ich-thee-o-sis) is derived from the Greek word ichthys meaning fish1.

 

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Image Reference2: Collodion Baby

As Mary and Dela held their baby with mixed feelings and with questions running through the minds, Felicity’s physical outward appearance made it obvious that she had a condition.  She had no hairs on her skin, her body was shiny all over almost as if she had been wrapped up in several layers of cling film and her lips and eye lids were bright red. As the weeks went by the layers of cling film began to peel off and her skin was covered in thick layers of dry fish–like scales all over with cracks in the skin. This scale formation is a result of the over production of skin cells and the body not being able to shed them off to match the rate of production hence causing a build-up.

 

 

 

Felicity’s appearance is typical of babies who present at birth with Ichthyosis and are referred to as having collodion skin. There are several forms of the condition with the most common being Ichthyosis Vulgaris. Rare forms of the disease, namely; Lamellar Ichthyosis, Harlequin Ichthyosis and Non-Bullous Ichthyosiform Erythroderma are collectively known as Autosomal Recessive Congenital Ichthyosis (ARCI).

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Image reference3: Scaly appearance of Ichthyoses sufferers

In my capacity as a research Scientist, the story of Mary, Dela and their beautiful baby Felicity sparked curiosity and just as the parents wanted answers, so did I. It was time to delve deeper into how baby Felicity’s skin came to be so different and how best to make her comfortable. With Ichthyosis being a genetic condition, it was clear how baby Felicity had acquired the disease. Both parents must have a copy of the faulty gene that fuses together for the disease to be activated.

Baby Felicity inherited both of these from her parents; hence the manifestation of the condition at birth. Further research has identified six main genes whose defect potentially leads to Ichthyosis, and these are TGM1, Alox12b, AloxE3, Ichthyin, ABCA12 and CYP4F22. Of these, the most common are TGM1, Alox12b and AloxE3.   Although the condition is genetic and the different forms are due to a different gene defect, the dry scaly outward appearance seen on the skin is common to all the conditions. This leads to the hypothesis that the sequence of events that happens after the body detects that something has gone wrong with the genetic makeup must be the same for all affected patients in order for them to exhibit the scaling observed. Not knowing exactly what the process is, means finding a cure has proven challenging. For babies like Felicity, the only option to stay comfortable from birth and throughout life is a combination of keeping the skin moisturised at all times to avoid cracks from dryness and regular scrubbing off of the dry scales. The use of retinoid based drugs which contain vitamin A, have also been shown to reduce the level of scaling, however, these usually have adverse side effects such as thinning of the bones. Other drugs which have been shown to reduce scaling include aspirin and urea based drugs. The exact mode of action via which these drugs reduce scaling is also unknown.

Not knowing exactly what the process is, means finding a cure has proven challenging

In trying to determine the common molecular mechanism that leads to scaling, we have to understand how the body usually responds to a faulty system. When the body detects a defect, it moves to quickly respond by sending certain cells and proteins to fight off the defect. Whiles these “first responders” hold off the damage, the body then recruits “secondary responders” to support and eventually take over from the first responders and ensure the defect does not reoccur. A bit like dialling 193 for a quick response where first aid is administered and being taken into hospital afterwards for a confirmed diagnosis and treatment.

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Image4: Mui Thomas. A Hong Kong rugby referee who suffers from Ichthyosis.

In the case of Ichthyosis, research has led us to believe that a possible cause of the common long term scaling observed in all patients is due to the body’s response to the damaged skin. So during skin formation at the early stages of a baby’s development, the defective genes inherited from the parents means that there is an error in the skin formation process. The body detects this error and sends out the first responders to hold off the error and subsequently sends out the second responders to hold off the defect. It is the action of the initial recruitment and the sustained protection of the defective skin barrier which manifests outwardly as the continuous formation of skin layers. Baby Felicity’s body really meant well, but unfortunately, no one is perfect and the body doesn’t always get it right. It can sometimes behave like the over protective parent who doesn’t know when to stop.

As a researcher, it is my job to now investigate these responders and hopefully find out who the hyperactive and enthusiastic bunch are and perhaps advise them to tone down the excitement, or perhaps who’s slacking on the job and get them to pull their weight. Once these can be narrowed down, Felicity’s condition can be treated and all that scrubbing, constant moisturising, daily pills for life and over protection of the skin can stop. Felicity can finally enjoy a normal life like everyone else.


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