Congenital lethal motor neuron disease with a novel defect in ribosome biogenesis
RJ Butterfield, TJ Stevenson, L Xing, TM Newcomb… - Neurology, 2014 - AAN Enterprises
Neurology, 2014•AAN Enterprises
Objective: We describe a novel congenital motor neuron disease with early demise due to
respiratory insufficiency with clinical overlap with spinal muscular atrophy with respiratory
distress (SMARD) type 1 but lacking a mutation in the IGHMBP2 gene. Methods: Exome
sequencing was used to identify a de novo mutation in the LAS1L gene in the proband.
Pathogenicity of the mutation was validated using a zebrafish model by morpholino-
mediated knockdown of las1l. Results: We identified a de novo mutation in the X-linked …
respiratory insufficiency with clinical overlap with spinal muscular atrophy with respiratory
distress (SMARD) type 1 but lacking a mutation in the IGHMBP2 gene. Methods: Exome
sequencing was used to identify a de novo mutation in the LAS1L gene in the proband.
Pathogenicity of the mutation was validated using a zebrafish model by morpholino-
mediated knockdown of las1l. Results: We identified a de novo mutation in the X-linked …
Objective
We describe a novel congenital motor neuron disease with early demise due to respiratory insufficiency with clinical overlap with spinal muscular atrophy with respiratory distress (SMARD) type 1 but lacking a mutation in the IGHMBP2 gene.
Methods
Exome sequencing was used to identify a de novo mutation in the LAS1L gene in the proband. Pathogenicity of the mutation was validated using a zebrafish model by morpholino-mediated knockdown of las1l.
Results
We identified a de novo mutation in the X-linked LAS1L gene in the proband (p.S477N). The mutation is in a highly conserved region of the LAS1L gene predicted to be deleterious by bioinformatic analysis. Morpholino-based knockdown of las1l, the orthologous gene in zebrafish, results in early lethality and disruption of muscle and peripheral nerve architecture. Coinjection of wild-type but not mutant human RNA results in partial rescue of the phenotype.
Conclusion
We report a patient with a SMARD phenotype due to a mutation in LAS1L, a gene important in coordinating processing of the 45S pre-rRNA and maturation of the large 60S ribosomal subunit. Similarly, the IGHMB2 gene associated with SMARD type 1 has been suggested to have an important role in ribosomal biogenesis from its role in processing the 45S pre-rRNA. We propose that disruption of ribosomal maturation may be a common pathogenic mechanism linking SMARD phenotypes caused by both IGHMBP2 and LAS1L.
American Academy of Neurology