Cystinosis in Latin America: insights from local experience on biochemical diagnosis
2Laboratorio de errores innatos del metabolismo. Hospital Universitario San Ignacio, Colombia
Background
Cystinosis is one of the treatable lysosomal storage disorders in which early diagnosis improves the patient’s prognosis and quality of life. In Latin America, the limited availability of intraleukocytary cysteine determination (ICL), the confirmatory biochemical test, hampers timely diagnosis and treatment, therefore cystinosis is an underdiagnosed condition. Herein, we summarise our experience since the local establishment of the test showing biochemical characteristics observed in our population.
Methods
This study involved a retrospective analysis of patient samples submitted for ICL quantification to our laboratory from 2017 to 2022.
Results
Since the establishment of the technique in our laboratory in 2017, we have detected 60 patients and processed 182 samples, of which 56% correspond to follow-up samples from 29 patients treated with cysteamine, with an average of 1.4 samples per year (ranging from 0.39 to 4.24). The age of patients analysed ranged between 2 months and 21 years old. Most positive samples have values between 1 and 5 nmol/1/2cystine/mg, although, in 25% of cases, values between 5 and 15 nmol/1/2cystine/mg were observed, and in one particular case, values up to 31 nmol/1/2cystine/mg were detected. In most follow-up samples, the highest detected value corresponds to the first determination, showing a subsequent tendency to decrease and stabilise between 1.5 and 2.5 nmol/1/2cystine/mg, with some cases presenting values even within the limits of normality.
Conclusion
Our data reveal that cystinosis is a relatively common condition in our country. The availability of ICL locally has improved the diagnosis and follow-up of patients. Our initial findings align with recent reports, although information on biochemical monitoring, particularly in Latin America, remains scarce. Therefore, it is important to share this type of information in academic and scientific circles to widen knowledge regarding cystinosis.
.png)