Public Health & Health Science Division, ULAB

Prokaryotes, such as bacteria, have evolved defense mechanisms that protect them from foreign bodies invading and harming them.1 One of these mechanisms is the clustered regularly interspaced short palindromic repeats (CRISPR), alongside their accompanying CRISPR-associated (Cas) proteins.1 This system functions as an immune response that protects prokaryotes from viruses (and other harmful bodies) by detecting foreign genetic material invading them and disabling their functionality and ability to spread.2 Understanding the underlying mechanism of this immune response allowed scientists around the world to develop CRISPR and adapt it to various uses in gene editing, agriculture, and most recently, diagnosis of infectious and noninfectious diseases.2  The discovery of CRISPR as a biomedical disease detection tool has revolutionized modern day medicine and its accessibility. 

Infectious diseases are those that are caused by microorganisms and easily passed from one human to another. Currently, CRISPR--specifically the Cas13 protein system--is being utilized for disease detection and diagnosis through the detection and cleavage of specific ssRNA molecules. SHERLOCK, Specific High-sensitivity Enzymatic Reporter unLOCKing, is a specific breed of CRISPR Cas13a disease detection technology that has been deployed in West African countries to combat infectious disease such as Lassa Fever-- a disease caused by the zoonotic virus Lassa mammarenavirus that originates from the Mastomys natalensis rodent group.5 SHERLOCK’s ability to succeed in the detection and diagnosis of Lassa fever in West African countries that lack proper infrastructure relies on SHERLOCK’s accessibility and efficiency. Cas13a’s specificity and sensitivity in the detection of viral nucleic acids caters to the fact that Lassa Fever has high genetic diversity and requires highly sensitive tools to detect the disease.8 

Moreover, genetic diseases are those caused by an error in the DNA of a person. The three main types include monogenic, complex, and chromosomal; the treatment and causes of the diseases are different for each type.17 There are still many obstacles when it comes to curing genetic diseases, yet scientists are using powerful tools such as CRISPR to help those who suffer from these diseases.18 The CRISPR Cas9 enzyme is one powerful system that can be used to disrupt, delete, or insert genes to help edit any errors in the genome and treat genetic diseases.23 It is comprised of the CRISPR-associated (Cas) enzyme and the guide RNA (gRNA), which work together to act as a scissor for the DNA.19 Adrenoleukodystrophy (ALD) is an X-linked genetic disease that is primarily due to a mutation within the ABCD1 gene. Currently, the Cas9 system provides a disease model in order to study the pathogenesis of ALD and target (and repair) the mutation causing this genetic disease.