by Ami Froehlich, Trustee
18 November to 18 December marks Disability History Month, with this year’s theme focused on Disability, Health and Well Being. UK Disability History Month (UK DHM) celebrates historical contributions of people with disabilities to society by raising awareness of challenges and structural barriers faced by them. To celebrate this years Disability History Month, we thought that we would look at the history of cystinosis and celebrate the progress that has been made in the development of treatments so far.
Cystinosis was the first documented genetic disease belonging to the group of lysosomal storage disease disorders. It is an autosomal recessive disorder caused by mutations of the CTNS gene on chromosome 17. About half of the cystinosis mutations in the Western populations are caused by a 57.2 kb deletion, this deletion is thought to have arisen in Northern Germany in about 500 AD.
Cystinosis was first described in medical literature in 1903 by Emil Abderhalden. In 1924, The Dutch pathologist George Lignac expanded on the observations of Aberhalden to point out that children with cystinosis often present with profound rickets. In 1931, the Swiss paediatrician, Guido Fanconi, was the first to perceive that cystinosis is associated with urinary wasting of substances that are normally reabsorbed during their passage through the renal tubules. With the recognition of renal Fanconi’s syndrome, clinicians were able to extend the lives of children with cystinosis by replacing the crucial nutrients lost in urine. Despite treatment of the renal Fanconi’s syndrome, children with cystinosis still went on to develop renal failure and did not usually survive past the age of 10-12 years. However, due to the development of renal transplantation surgery during the 20th century, a study in 1970 by Mahoney et al. reported excellent renal allograft survival in four children with cystinosis and found that there was no evidence of recurrent cystinosis in the donated kidney.
In the late 1960s, investigators at the US National Institutes of Health discovered that the accumulation of cystine in patient tissues was due to a defect in the lysosomes within the cells. In 1976 Dr Jerry Schneider reported that cysteamine could react with cystine, allowing the resulting mixed disulphides to escape via alternative channels in the lysosomal membrane. Dr William Gahl went on to organise a North American trial of cysteamine that demonstrated slowing of progressive renal failure, particularly in those children who began therapy before the age of two years and were adherent to the prescribed dose. In a retrospective review of 100 adults with cystinosis, Gahl reported that late complications of cystinosis, such as muscle wasting and hypothyroidism, decreased with time on cysteamine therapy. The development of cysteamine therapy transformed cystinosis from a fatal disorder of childhood to a treatable chronic disease, with a generation of adults living long after their predicted lifespans when they were first diagnosed.