Neuropathy target esterase impairments cause Oliver-McFarlane and Laurence-Moon syndromes.

Abstract

BACKGROUND:

Oliver-McFarlane syndrome is characterised by trichomegaly, congenital hypopituitarism and retinal degeneration with choroidal atrophy. Laurence-Moon syndrome presents similarly, though with progressive spinocerebellar ataxia and spastic paraplegia and without trichomegaly. Both recessively inherited disorders have no known genetic cause.

METHODS:

Whole-exome sequencing was performed to identify the genetic causes of these disorders. Mutations were functionally validated in zebrafish pnpla6 morphants. Embryonic expression was evaluated via in situ hybridisation in human embryonic sections. Human neurohistopathology was performed to characterise cerebellar degeneration. Enzymatic activities were measured in patient-derived fibroblast cell lines.

RESULTS:

Eight mutations in six families with Oliver-McFarlane or Laurence-Moon syndrome were identified in the PNPLA6 gene, which encodes neuropathy target esterase (NTE). PNPLA6 expression was found in the developing human eye, pituitary and brain. In zebrafish, the pnpla6 curly-tailed morphant phenotype was fully rescued by wild-type human PNPLA6 mRNA and not by mutation-harbouring mRNAs. NTE enzymatic activity was significantly reduced in fibroblast cells derived from individuals with Oliver-McFarlane syndrome. Intriguingly, adult brain histology from a patient with highly overlapping features of Oliver-McFarlane and Laurence-Moon syndromes revealed extensive cerebellar degeneration and atrophy.

CONCLUSIONS:

Previously, PNPLA6 mutations have been associated with spastic paraplegia type 39, Gordon-Holmes syndrome and Boucher-Neuhäuser syndromes. Discovery of these additional PNPLA6-opathies further elucidates a spectrum of neurodevelopmental and neurodegenerative disorders associated with NTE impairment and suggests a unifying mechanism with diagnostic and prognostic importance.

• Authors: Robert B Hufnagel, Gavin Arno, Nichole D Hein, Joshua Hersheson, Megana Prasad, Yvonne Anderson, Laura A Krueger, Louise C Gregory, Corinne Stoetzel, Thomas J Jaworek, Sarah Hull, Abi Li, Vincent Plagnol, Christi M Willen, Thomas M Morgan, Cynthia A Prows, Rashmi S Hegde, Saima Riazuddin, Gregory A Grabowski, Rudy J Richardson, Klaus Dieterich, Taosheng Huang, Tamas Revesz, J P Martinez-Barbera, Robert A Sisk, Craig Jefferies, Henry Houlden, Mehul T Dattani, John K Fink, Helene Dollfus, Anthony T Moore, Zubair M Ahmed
• Journal: Journal of medical genetics (J Med Genet) Vol. 52 Issue 2 Pg. 85-94 (Feb 2015) ISSN: 1468-6244 [Electronic] England
• PMID: 25480986 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Chemical References

• PNPLA6 protein, human
• Phospholipases
• Carboxylic Ester Hydrolases
• neurotoxic esterase

Topics

• Alleles
• Amino Acid Sequence
• Animals
• Blepharoptosis (enzymology, genetics)
• Carboxylic Ester Hydrolases (chemistry, genetics)
• Central Nervous System (pathology)
• Developmental Disabilities (enzymology, genetics)
• Dwarfism (enzymology, genetics)
• Embryonic Development (genetics)
• Gene Expression Regulation, Developmental
• Genetic Predisposition to Disease
• Humans
• Hypertrichosis (enzymology, genetics)
• Intellectual Disability (enzymology, genetics)
• Laurence-Moon Syndrome (enzymology, genetics)
• Molecular Sequence Data
• Mutation (genetics)
• Phenotype
• Phospholipases (chemistry, genetics)
• Protein Structure, Tertiary
• Retina (pathology)
• Retinitis Pigmentosa (enzymology, genetics)
• Zebrafish (embryology)