👤 Tina Lamey

Mutations in CLN3 cause Batten disease, however non-syndromic CLN3 disease, characterized by retinal-specific degeneration, has been also described. Here, we characterized an induced pluripotent stem cell (iPSC)-derived disease model derived from a patient with non-syndromic CLN3-associated retinopathy. Patient-iPSC, carrying the 1 kb-deletion and c.175G>A variants in CLN3, coisogenic iPSC, in which the c.175G>A variant was corrected, and control iPSC were differentiated into neural retinal organoids (NRO) and cardiomyocytes. CLN3 transcripts were analyzed by Sanger sequencing. Gene expression was characterized by qPCR and western blotting. NRO were characterized by immunostaining and electron microscopy. Novel CLN3 transcripts were detected in adult human retina and control-NRO. The major transcript detected in patient-NRO displayed skipping of exons 2 and 4-9. Accumulation of subunit-C of mitochondrial ATPase (SCMAS) protein was demonstrated in patient-derived cells. Photoreceptor progenitor cells in patient-NRO displayed accumulation of peroxisomes and vacuolization of inner segments. Correction of the c.175G>A variant restored CLN3 mRNA and protein expression and prevented SCMAS and inner segment vacuolization. Our results demonstrate the expression of novel CLN3 transcripts in human retinal tissues. The c.175G>A variant alters splicing of the CLN3 pre-mRNA, leading to features consistent with CLN3 deficiency, which were prevented by gene correction. Show less

Mutation of the CLN3 gene, associated with juvenile neuronal ceroid lipofuscinosis, has recently been associated with late-onset, non-syndromic retinal dystrophy. Herein we describe the multimodal imaging, immunological and systemic features of an adult with compound heterozygous CLN3 mutations. A 50-year-old female with non-syndromic retinal dystrophy from the age of 36 years underwent multimodal retinal imaging, electroretinography, neuroimaging, immunological studies and genetic testing. CLN3 transcripts were amplified from patient leukocytes by reverse transcriptase polymerase chain reaction and characterized by Sanger sequencing. Visual acuity declined to 6/12 and 6/76 due to asymmetrical central scotoma. ERG responses became electronegative and patient's serum contained anti-retinal antibodies. Final visual acuity stabilized at 6/60 bilaterally 3 years after peri-ocular steroid and rituximab infusion. Genetic testing revealed compound heterozygous CLN3 mutations: the 1.02 kb deletion and a novel missense mutation (c.175G>A). In silico, analyses predicted the c.175G>A mutation disrupted an exonic splice enhancer site in exon 3. In patient leukocytes, CLN3 expression was reduced and novel CLN3 transcripts lacking exon 3 were detected. Our case study shows that (1) non-syndromic CLN3 disease leads to rod and delayed primary cone degeneration resulting in constricting peripheral field and enlarging central scotoma and, (2) the c.175G>A CLN3 mutation, altered splicing of the CLN3 gene. Overall, we provide comprehensive clinical characterization of a patient with non-syndromic CLN3 disease. Show less

We report the generation of the human iPSC line LEIi004-A from a patient with late-onset non-syndromic retinitis pigmentosa caused by compound heterozygous mutations in the CLN3 gene. Reprogramming of primary dermal fibroblasts was performed using episomal plasmids containing OCT4, SOX2, KLF4, L-MYC, LIN28, shRNA for p53 and mir302/367 microRNA. To create a coisogenic control line, one CLN3 variant was corrected in the patient-iPSC using CRISPR/Cas9 gene editing to generate the iPSC line LEIi004-A-1. Show less