Gene 537 (2014) 352–356

Contents lists available at ScienceDirect

Gene

j ourna l homepage: www.e lsev ie r .com/ locate /gene

Short Communication

C19orf12 mutation leads to a pallido-pyramidal syndrome

Michael C. Kruer a,b,⁎,1, Mustafa A. Salih c,1, Catherine Mooney d, Jawahir Alzahrani e, Salah A. Elmalik f,Mohammad M. Kabiraj g, Arif O. Khan h, Reema Paudel i, Henry Houlden i,Hamid Azzedine j,2, Fowzan Alkuraya e,k,l,2

a Sanford Children's Health Research Center, Sioux Falls, SD, USAb Division of Pediatric Neurology, Sanford Children's Specialty Clinic, Sioux Falls, SD, USAc Division of Pediatric Neurology, College of Medicine, King Saud University,Riyadh, Saudi Arabiad School of Medicine and Medical Science, University College Dublin, Dublin, Ireland, UKe Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabiaf Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabiag Department of Neurosciences, Armed Forces Hospital, Riyadh, Saudi Arabiah Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabiai Reta Lila Weston Laboratories and Department of Molecular Neuroscience, UKj Department of Medical Genetics, Faculty of Biology and Medicine, University of Lausanne, Switzerlandk Department of Pediatrics, King Khalid University Hospital and College of Medicine, King Saud University, Riyadh, Saudi Arabial Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia

Abbreviations:NBIA, neurodegeneration with brain iroresonance imaging; MCV, motor conduction velocity; SNAtial; DML, distal motor latency; CMAP, compound motoevoked potential; ERG, electroretinogram; BAER, brainstbp, base pairs; Mb, megabase.⁎ Corresponding author at:. Sanford Children's Health R

North, Sioux Falls, SD 57104, USA.E-mail address: michael.kruer@sanfordhealth.org (M.C

1 These authors should be considered joint first author2 These authors should be considered joint senior auth

0378-1119/$ – see front matter © 2013 Elsevier B.V. All rhttp://dx.doi.org/10.1016/j.gene.2013.11.039

a b s t r a c t

a r t i c l e i n f o

Article history:Accepted 19 November 2013Available online 17 December 2013

Keywords:Neurodegenerative diseaseMovement disordersNeurogenetics

Pallido-pyramidal syndromes combine dystonia with or without parkinsonism and spasticity as part of a mixedneurodegenerative disorder. Several causative genes have been shown to lead to pallido-pyramidal syndromes,including FBXO7, ATP13A2, PLA2G6, PRKN and SPG11. Among these, ATP13A2 and PLA2G6 are inconsistentlyassociatedwith brain irondeposition. Usinghomozygositymapping and direct sequencing in amultiplex consan-guineous Saudi Arabian family with a pallido-pyramidal syndrome, iron deposition and cerebellar atrophy, weidentified a homozygous p.G53R mutation in C19orf12. Our findings add to the phenotypic spectrum associatedwith C19orf12 mutations.

© 2013 Elsevier B.V. All rights reserved.

1. Introduction

Pallido-pyramidal disorders are neurodegenerative syndromes thatcombine dystonia and/or parkinsonism with pyramidal tract findings(Bronstein and Vickrey, 1996). Pallido-pyramidal syndromes may becaused by mutations in PLA2G6, ATP13A2, FBXO7, SPG11, and PRKN(Paisán-Ruiz et al., 2010). Clinical features can include dementia, neuro-psychiatric features, neuropathy, and ataxia in addition to thepyramidaland extrapyramidal features of the disease (Di Fonzo et al., 2009;Wickremaratchi et al., 2009). We report the identification of mutationsin C19orf12 in a multiplex, consanguineous Saudi kindred clinicallycharacterized as pallido-pyramidal syndrome. Our findings and thoseof other investigators indicate that substantial overlap exists between

n accumulation;MRI, magneticP, sensory nerve action poten-r action potential; VEP, visualem auditory evoked response;

esearch Center, 2301 E. 60th St

. Kruer).s.ors.

ights reserved.

pallido-pyramidal andneurodegenerationwith brain iron accumulationsyndromes.

2. Materials & methods

2.1. Patients

The probands derived from a multiplex, consanguineous Saudi ped-igree (Fig. 1).

2.2. Patient 1 (VII:5)

The patientwas amale born at term after an unremarkable pregnan-cy. Early milestones were attained at appropriate ages, and the patientwalked at age 1. At 4 years of age, the patient developed an abnormalgait. A progressive motor decline ensued, leaving the patient relianton a wheelchair for locomotion at age 17. Dementia became evidentin late adolescence, with anxiety and phobias emerging at that time. Ex-amination at age 20 disclosed persistent nystagmus on lateral gaze, dis-tal muscle wasting of the upper and lower limbs (Fig. 1), upper limbdystonia and pyramidal tract signs of the upper and lower limbs,with kyphoscoliosis of the cervical and thoracic spine, and flexion

353M.C. Kruer et al. / Gene 537 (2014) 352–356

contractures of the knee joints, and pes equinovarus foot deformities bi-laterally. Evoked motor potentials demonstrated slowed velocity andreduced amplitude. MRI demonstrated bilateral T2 hypointensity ofthe globus pallidus and substantia nigra.

2.3. Patient 2 (VII:7)

This patient is the brother of Patient 1, was also born at term after anunremarkable pregnancy. He walked at 1 year, and developed gait

Fig. 1. Index family. (A) Family pedigree. (B) Distal wasting of the upper limbs. Atrophy of the thdemonstrates T2 hypointensity of the globus pallidus (blue-lined arrows), substantia nigra (rederences to color in this figure legend, the reader is referred to the web version of this article.)

impairment at age 6 years. Gait progressively declined, and cognitiveimpairment was noted in adolescence. Examination at age 15 years re-vealed anxiety with self-injurious behaviors, insomnia, and slowed ver-tical saccades. Bradykinesia and pyramidal tract signswere evident, andbilateral equinovarus deformities were noted. Echocardiogram, lipidpanel, and blood smear for acanthocytes were negative. Nerve conduc-tion studies (done at the age of 15 years) showed normal motor con-duction velocity (MCV) and distal motor latency (DML) of median,ulnar and tibial nerves. Compound motor action potential amplitudes

enar and hypothenarmuscles. (C)MRI features of affected individuals. MRI from patient 3-lined arrows), and cerebellar atrophy (green-lined arrow). (For interpretation of the ref-

Fig. 1 (continued).

354 M.C. Kruer et al. / Gene 537 (2014) 352–356

(CMAPs) of median and ulnar nerves were normal, while that of tibialnerve was slightly reduced (2.3 mV). Sensory nerve action potentialamplitudes (SNAPs) of median, ulnar and sural nerves were normal.Electromyography (EMG) revealed normal findings. Visual evoked po-tentials (VEP), electroretinography (ERG) and brain auditory evoked re-sponses (BAER) revealed normal results. MRI exhibited T2hypointensity of the globus pallidus and substantia nigra.

2.4. Patient 3 (VII:2)

This patient was also born at term, andwalked at age 15 months. Atage 9, he developed ataxia and cognitive impairment. At age 10, he de-veloped spasticity of the lower limbs. At the time of most recent exam-ination at age 16, the patient exhibited gait impairment, bradykinesia,and pyramidal tract signs. MRI disclosed evidence of cerebellar atrophyin addition to T2 hypointensity of the globus pallidus and substantianigra (Fig. 1).

2.5. Genotyping

Genomic DNAwas extracted from blood using established methods.Sanger sequencing excluded pathogenic variants in PANK2 and PLA2G6prior to genotyping. Primers were designed to span coding exons ofeach gene along with 10–20 bp of adjacent intronic sequences (se-quences available upon request). Genotyping was performed on theAxiom platform following the manufacturer's instructions (Affymetrix,Santa Clara, CA). Homozygosity mapping was performed usingautoSNPa as previously described (Carr et al., 2006).

Fig. 2. Catalog of C19orf12mutations. Shown are reportedmutations (Deschauer et al., 2012; De2013; Horvath et al., 2012; Landouré et al., 2013; Panteghini et al., 2012; Schottmann et al., 201cluster around the putative transmembrane region.

3. Results

3.1. Genotyping

A total of 5 homozygous regions greater than 1 Mb segregatingwithaffected status were identified. We focused on the largest run of homo-zygosity on chromosome 19 (hg19: 13,430,747-24,360,538).

3.2. Sequencing

Mutations in C19orf12 have previously been shown to lead to a phe-notype similar to that seen with PLA2G6mutation (Kruer and Boddaert,2012). As C19orf12 fell within the identified linkage interval, Sanger se-quencing of the C19orf12 genewas performed. This analysis identified ahomozygous c.157GNA, p.G53R (NM_001031726.2) mutation in all af-fected family members. The p.G53R mutation falls within the protein'sputative transmembrane region as do several other reported pathogenicmutations (Fig. 2).

3.3. In silico analysis

Although this sequence variant is listed as rs200133991 in dbSNP(http://www.ncbi.nlm.nih.gov/projects/SNP/), the variant is predictedto be “deleterious” by SIFT (http://sift.jcvi.org) and “probably damag-ing” by PolyPhen2 [score 1.0] (http://genetics.bwh.harvard.edu/pph2).The p.G53R sequence change affects a residue that is highly conservedbetween species down to Danio rerio. The 1000Genomes database(http://www.1000genomes.org/) annotates the allele frequencies of

zfouli et al., 2012; Dogu et al., 2013; Goldman et al., 2013; Hartig et al., 2011; Hogarth et al.,3; Schulte et al., 2013), including the present one based on UniProtKB Q9NSK7. Mutations

Fig.

3.In

silicoan

alysisof

theeffect

ofp.G53

Ron

proteinbind

ingregion

s,seco

ndarystructure,intrinsicdisorder

andtran

smem

bran

edo

mainpred

iction

.The

reislittlech

ange

inthepred

ictedseco

ndarystructure,proteindisorder

orsh

ortlin

ear

protein-bind

ingmotifs

(SLiMs).A

ltho

ughsomealgo

rithmspred

ictedno

orsm

allc

hang

esin

thepu

tative

tran

smem

bran

e(TM)region

[MEM

SAT-SV

M/M

EMSA

T3(m

agen

ta),PR

O(cya

n),P

RODIV

(blue),P

olyP

hobius

(yellow),PH

Dhtm

(orang

e),

SMART

/TMHMM

(green

),UniProt

(red

)],C

19orf12isan

notatedby

Pfam

asaglycinezipp

er-con

tainingOmpA

-likemem

bran

edo

main.

Glycine

-zippe

rmotifs

(typ

ically

Gxx

xGxx

xGrepe

ats)

strong

lydriverigh

t-ha

nded

helix

packingan

dmutations

inthemotifcanblockch

anne

lformation(Pun

taet

al.,20

12).Th

ep.G53

Rmutationdisrup

tsthisim

portan

tstructural

motif,

possibly

disrup

ting

TMregion

arch

itecture

(assh

ownby

chan

gesin

TMregion

pred

iction

).

355M.C. Kruer et al. / Gene 537 (2014) 352–356

the C (G) and T (A) nucleotides (YRI) as: C: 0.994, T: 0.006, indicatingthat this sequence variant represents a rare allele. In addition,c.157GNA has been previously reported as pathogenic in heterozygousform (Hartig et al., 2011).

Short linear protein binding motifs (SLiMs) were predicted usingSLiMPred (Mooney et al., 2012), protein intrinsic disorder was predict-ed with IUPred (Dosztanyi et al., 2005) and three class protein second-ary structure (Helix, Strand and Coil) was predicted by Distill (Bauet al., 2006). Transmembrane regions were predicted using publishedalgorithms (Krogh et al., 2001; Letunic et al., 2012; Nugent et al.,2011; Punta et al., 2012; Rost et al., 2004; Viklund and Elofsson,2004). In silico mutation modeling indicated that the sequence changewould have little effect on secondary structure or short linear proteininteractingmotifs (Fig. 3) suggesting that abnormal protein–lipid inter-actions may account for this mutation's pathogenicity, perhaps byimpairing insertion within the mitochondrial membrane. Consistentwith such a paradigm, the p.G53R mutation is predicted to disrupt aglycine zipper motif crucial for membrane interaction (Fig. 3) (Kimet al., 2005).

4. Discussion

We thus report a homozygous p.G53R mutation in C19orf12, a re-cently identified cause of neurodegenerationwith brain iron accumula-tion (NBIA4) (Hartig et al., 2011) in a largemultiplex Saudi family witha pallido-pyramidal syndrome. All affected patients presented withataxia that was later overshadowed by spasticity and dystonia-parkinsonism. In one patient, cerebellar atrophywas evident on cranialMRI in association with clinical ataxia. There was no evidence of opticatrophy in this family. Peripheral neuropathy was not seen in the case(Patient 2) who had detailed neurophysiologic testing at the age of15 years. Nevertheless, evoked motor potentials demonstrated slowedvelocity and reduced amplitude in Patient 1 at the age of 20 years, sug-gesting that the distal muscle wasting found on examination (Fig. 1) isdue to a central axonopathy rather than peripheral nerve involvement.

Our findings indicate that mutations in C19orf12 should be con-sidered in the differential diagnosis of patients presenting withpallido-pyramidal syndromes. Unlike patients with mutations inFBXO7, SPG11 and PRKN, who can also present with a pallido-pyramidal syndrome (Paisán-Ruiz et al., 2010), patients withC19orf12 mutations typically exhibit brain iron deposition in theglobus pallidus and substantia nigra (Dezfouli et al., 2012; Doguet al., 2013; Goldman et al., 2013; Hogarth et al., 2013; Horvathet al., 2012; Panteghini et al., 2012; Schottmann et al., 2013;Schulte et al., 2013) similar tomany patients with PLA2G6mutations(Kruer and Boddaert, 2012). Patients with ATP13A2 typically alsopresent with pallido-pyramidal syndrome, but only rarely demon-strate accumulation of brain iron (Schneider et al., 2010). Our find-ings suggest that c19orf12 should be considered in PLA2G6-negative pallido-pyramidal syndromes. Interestingly, many patientswith mutations in PLA2G6 do not feature brain iron deposition, andit is not known whether iron deposition in the brain is an invariantfeature of C19orf12-associated disease.

Patients with C19orf12 mutations can present quite variably, withadditional phenotypes including hereditary spastic paraplegia(Landouré et al., 2013) and a juvenile amytrophic lateral sclerosis-likephenotype (Deschauer et al., 2012). It remains to be seen to what de-gree mutations in genes that lead to similar clinical presentations willbe found to intersect in common pathways at the molecular level, al-though in the case of PRKN and FBXO7, a joint role in controllingmitophagy has recently been shown (Burchell et al., 2013).

Conflict of interest

No conflicts.

356 M.C. Kruer et al. / Gene 537 (2014) 352–356

Acknowledgments

We thank the patients and their family, without whom this workwould not have been possible. Portions of this work were supportedby the Dystonia Medical Research Foundation (MCK), the Child Neurol-ogy Foundation and the NIH NINDS (NS083739) (MCK). MAS was sup-ported by the Deanship of Scientific Research, King Saud University,Riyadh, Saudi Arabia through the research group project number RGP-VPP-301.

References

Bau, D., Martin, A., Mooney, C., Vullo, A., Walsh, I., Pollastri, G., 2006. Distill: a suite of webservers for the prediction of one-, two-and three-dimensional structural features ofproteins. BMC Bioinforma. 7 (1), 402.

Bronstein, J., Vickrey, B., 1996. Pallido-pyramidal syndrome. Parkinsonism Relat. Disord. 2(2), 105–106 (Apr).

Burchell, V.S., et al., 2013. The Parkinson's disease-linked proteins Fbxo7 and Parkin inter-act to mediate mitophagy. Nat. Neurosci. 16 (9), 1257–1265 (Sep).

Carr, I.M., Flintoff, K., Taylor, G.R., Markham, A.F., Bonthron, D.T., 2006. Interactive visualanalysis of SNP data for rapid autozygosity mapping in consanguineous families.Hum. Mutat. 27, 1041–1046.

Deschauer, M., Gaul, C., Behrmann, C., Prokisch, H., Zierz, S., Haack, T.B., 2012. C19orf12mutations in neurodegeneration with brain iron accumulation mimicking juvenileamyotrophic lateral sclerosis. J. Neurol. 259 (11), 2434–2439.

Dezfouli, M.A., et al., 2012. PANK2 and C19orf12 mutations are common causes of neuro-degeneration with brain iron accumulation. Mov. Disord. http://dx.doi.org/10.1002/mds.25271 (Nov 19, Epub ahead of print).

Di Fonzo, A., et al., 2009. FBXO7 mutations cause autosomal recessive, early-onsetparkinsonian-pyramidal syndrome. Neurology 72 (3), 240–245 (Jan 20).

Dogu, O., et al., 2013. Rapid disease progression in adult-onset mitochondrial membraneprotein-associated neurodegeneration. Clin. Genet. 84 (4), 350–355 (Oct).

Dosztanyi, Z., Csizmok, V., Tompa, P., Simon, I., 2005. IUPred: web server for the predictionof intrinsically unstructured regions of proteins based on estimated energy content.Bioinformatics 21 (16), 3433–3434.

Goldman, J.G., et al., 2013. Clinical features of neurodegeneration with brain ironaccumulation due to a C19orf12 gene mutation. Mov. Disord. 28 (10), 1462–1463.http://dx.doi.org/10.1002/mds.25410 (Sep, Epub 2013 Mar 13).

Hartig, M.B., et al., 2011. Absence of an orphan mitochondrial protein, c19orf12, causes adistinct clinical subtype of neurodegeneration with brain iron accumulation. Am.J. Hum. Genet. 89 (4), 543–550.

Hogarth, P., et al., 2013. New NBIA subtype: genetic, clinical, pathologic, and radiographicfeatures of MPAN. Neurology 80 (3), 268–275 (Jan 15).

Horvath, R., et al., 2012. A new phenotype of brain iron accumulation withdystonia, optic atrophy, and peripheral neuropathy. Mov. Disord. 27 (6),789–793.

Kim, S., Jeon, T.J., Oberai, A., Yang, D., Schmidt, J.J., Bowie, J.U., 2005. Transmembrane gly-cine zippers: physiological and pathological roles in membrane proteins. Proc. Natl.Acad. Sci. U. S. A. 102 (40), 14278–14283.

Krogh, A., Larsson, B., von Heijne, G., Sonnhammer, E.L.L., 2001. Predicting transmem-brane protein topology with a hidden Markov model: application to complete ge-nomes. J. Mol. Biol. 305, 567–580.

Kruer, M.C., Boddaert, N., 2012. Neurodegeneration with brain iron accumulation: a diag-nostic algorithm. Semin. Pediatr. Neurol. 19 (2), 67–74 (Jun).

Landouré, G., et al., 2013. Hereditary spastic paraplegia Type 43 (SPG43) is caused bymu-tation in C19orf12. Hum. Mutat. 34 (10), 1357–1360 (Oct).

Letunic, I., Doerks, T., Bork, P., 2012. SMART 7: recent updates to the protein domain an-notation resource. Nucleic Acids Res. 40 (D1), D302–D305.

Mooney, C., Pollastri, G., Shields, D.C., Haslam, N.J., 2012. Prediction of short linear proteinbinding regions. J. Mol. Biol. 415 (1), 193–204.

Nugent, T., Ward, S., Jones, D.T., 2011. The MEMPACK alpha-helical transmembrane pro-tein structure prediction server. Bioinformatics 27, 1438–1439.

Paisán-Ruiz, C., et al., 2010. Early-onset L-dopa-responsive parkinsonism with pyramidalsigns due to ATP13A2, PLA2G6, FBXO7 and spatacsinmutations. Mov. Disord. 25 (12),1791–1800.

Panteghini, C., et al., 2012. C19orf12 and FA2Hmutations are rare in Italian patients withneurodegeneration with brain iron accumulation. Semin. Pediatr. Neurol. 19 (2),75–81.

Punta, M., et al., 2012. The Pfam protein families database. Nucleic Acids Res. 40,D290–D301 (Database issue).

Rost, B., Yachdav, G., Liu, J., 2004. The PredictProtein Server. Nucleic Acids Res. 32,W321–W326 (Web Server issue).

Schneider, S.A., et al., 2010. ATP13A2 mutations (PARK9) cause neurodegeneration withbrain iron accumulation. Mov. Disord. 25 (8), 979–984 (Jun 15).

Schottmann, G., Stenzel, W., Lützkendorf, S., Schuelke, M., Knierim, E., 2013. A novelframeshift mutation of C19ORF12 causes NBIA4 with cerebellar atrophy and mani-fests with severe peripheral motor axonal neuropathy. Clin. Genet. http://dx.doi.org/10.1111/cge.12137 (Mar 25, Epub ahead of print).

Schulte, E.C., et al., 2013. Mitochondrial membrane protein associated neurodegenration:a novel variant of neurodegeneration with brain iron accumulation. Mov. Disord. 28(2), 224–227 (Feb).

Viklund, H., Elofsson, A., 2004. Best alpha-helical transmembrane protein topology pre-dictions are achieved using hidden Markov models and evolutionary information.Protein Sci. 13, 1908–1917.

Wickremaratchi, M.M., et al., 2009. Parkin-related disease clinically diagnosed as apallido-pyramidal syndrome. Mov. Disord. 24 (1), 138–140 (Jan 15).