Posterior column ataxia with retinitis pigmentosa coexisting with sensory-autonomic neuropathy and leukemia due to the homozygous p.Pro221Ser FLVCR1 mutation.

Abstract

FLVCR1 encodes for a ubiquitous heme exporter, whose recessive mutations cause posterior column ataxia with retinitis pigmentosa (PCARP). Recently, FLVCR1 recessive mutations were also found in two sporadic children with hereditary sensory-autonomic neuropathy (HSAN). We report the unique case of a 33-year-old Italian woman with a combination of typical PCARP, sensory-autonomic neuropathy with sensory loss to all modalities and multiple autonomic dysfuctions, and acute lymphocytic leukemia. Molecular analysis demonstrated homozygosity for the previously identified FLVCR1 p.Pro221Ser variation. The same variation, in combination with a frameshift mutation, was previously identified in an Italian child with HSAN. Functional studies carried out on patient-derived lymphoblastoid cell lines showed decreased FLVCR1a transcript, increased reactive oxygen species, excessive intracellular heme accumulation, and increased number of Annexin V positive cells. This indicates that the homozygous p.Pro221Ser FLVCR1 variation compromises the ability of FLVCR1a to export heme leading to enhanced susceptibility to programmed cell death. Our study demonstrates the existence of a phenotypic continuum among the discrete disorders previously linked to FLVCR1 mutations, and suggests that the related alteration of heme metabolism may lead to the degeneration of specific neuronal cell populations.

• Authors: Marco Castori, Silvia Morlino, Martin Ungelenk, Davide Pareyson, Ettore Salsano, Paola Grammatico, Emanuela Tolosano, Ingo Kurth, Deborah Chiabrando
• Journal: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics (Am J Med Genet B Neuropsychiatr Genet) Vol. 174 Issue 7 Pg. 732-739 (Oct 2017) ISSN: 1552-485X [Electronic] United States
• PMID: 28766925 (Publication Type: Case Reports, Journal Article)
• Copyright: © 2017 Wiley Periodicals, Inc.

Chemical References

• FLVCR1 protein, human
• Membrane Transport Proteins
• Receptors, Virus

Topics

• Adult
• Ataxia (complications, genetics, pathology)
• Female
• Hereditary Sensory and Autonomic Neuropathies (complications, genetics, pathology)
• Homozygote
• Humans
• Leukemia (complications, genetics, pathology)
• Membrane Transport Proteins (genetics)
• Mutation
• Pedigree
• Prognosis
• Receptors, Virus (genetics)
• Retinitis Pigmentosa (complications, genetics, pathology)