The expanding<i>LARS2</i>phenotypic spectrum: HLASA, Perrault syndrome with leukodystrophy, and mitochondrial myopathy
Lisa G. Riley, Joëlle Rudinger‐Thirion, Magali Frugier, Meredith Wilson, Melissa Luig, Thushari I. Alahakoon, Cheng Yee Nixon, Edwin P. Kirk, Tony Roscioli, Sebastian Lunke, Zornitza Stark, Klaas J. Wierenga, Sirish Palle, Maie Walsh, Emily Higgs, Susan Arbuckle, Shalini Thirukeswaran, Alison G. Compton, David R. Thorburn, John Christodoulou
Abstract
LARS2 variants are associated with Perrault syndrome, characterized by premature ovarian failure and hearing loss, and with an infantile lethal multisystem disorder: Hydrops, lactic acidosis, sideroblastic anemia (HLASA) in one individual. Recently we reported LARS2 deafness with (ovario) leukodystrophy. Here we describe five patients with a range of phenotypes, in whom we identified biallelic LARS2 variants: three patients with a HLASA-like phenotype, an individual with Perrault syndrome whose affected siblings also had leukodystrophy, and an individual with a reversible mitochondrial myopathy, lactic acidosis, and developmental delay. Three HLASA cases from two unrelated families were identified. All were males with genital anomalies. Two survived multisystem disease in the neonatal period; both have developmental delay and hearing loss. A 55-year old male with deafness has not displayed neurological symptoms while his female siblings with Perrault syndrome developed leukodystrophy and died in their 30s. Analysis of muscle from a child with a reversible myopathy showed reduced LARS2 and mitochondrial complex I levels, and an unusual form of degeneration. Analysis of recombinant LARS2 variant proteins showed they had reduced aminoacylation efficiency, with HLASA-associated variants having the most severe effect. A broad phenotypic spectrum should be considered in association with LARS2 variants.