Adaptor proteins (AP 1-5) are heterotetrameric complexes that facilitate specialized cargo sorting in vesicular-mediated trafficking. Mutations in AP5Z1, encoding a subunit of the AP-5 complex, have been reported to cause hereditary spastic paraplegia (HSP), although their impact at the cellular level has not been assessed. Here we characterize three independent fibroblast lines derived from skin biopsies of patients harbouring nonsense mutations in AP5Z1 and presenting with spastic paraplegia accompanied by neuropathy, parkinsonism and/or cognitive impairment. In all three patient-derived lines, we show that there is complete loss of AP-5 ζ protein and a reduction in the associated AP-5 µ5 protein. Using ultrastructural analysis, we show that these patient-derived lines consistently exhibit abundant multilamellar structures that are positive for markers of endolysosomes and are filled with aberrant storage material organized as exaggerated multilamellar whorls, striated belts and 'fingerprint bodies'. This phenotype can be replicated in a HeLa cell culture model by siRNA knockdown of AP-5 ζ. The cellular phenotype bears striking resemblance to features described in a number of lysosomal storage diseases (LSDs). Collectively, these findings reveal an emerging picture of the role of AP-5 in endosomal and lysosomal homeostasis, illuminates a potential pathomechanism that is relevant to the role of AP-5 in neurons and expands the understanding of recessive HSPs. Moreover, the resulting accumulation of storage material in endolysosomes leads us to propose that AP-5 deficiency represents a new type of LSDs. ; This work was supported by the Wellcome Trust (086598; J.H., J.R.E. and M.S.R.), the European Union (OMICS Call, Neuromics project; F.D., A.D., T.E. and G.S.), Verum Foundation (G.S.), Programme d'Investissement d'Avenir (ANR-10-IAIHU-06; F.D., A. D., T.E. and G.S.), ERC starting grant (311149; F.D.), the Intramural Research Program of the NINDS, National Institutes of Health (J.C., R.H.R. and C.B.) and National Institutes of Health grant NS083739 (M.M. and M.C.K.), Doris Duke Foundation (Clinical Scientist Development Award to M.C.K.) and Healthcare Research of the Italian Ministry of Health (C.M. and C.G.). C.G. also received partial research support by AriSLA (NOVALS 2010). Funding to pay the Open Access publication charges for this article was provided by the Wellcome Trust. ; This is the final version. It was first published by OUP at http://dx.doi.org/10.1093/hmg/ddv220
Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation. Objective: To identify the genetic variants associated with juvenile ALS. Design, Setting, and Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism. Main Outcomes and Measures: De novo variants present only in the index case and not in unaffected family members. Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway. Conclusions and Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.
International audience ; Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, setting, and participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main outcomes and measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and ...
International audience ; Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, setting, and participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main outcomes and measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and ...
International audience ; Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, setting, and participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main outcomes and measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and ...
IMPORTANCE: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation. OBJECTIVE: To identify the genetic variants associated with juvenile ALS. DESIGN, SETTING, AND PARTICIPANTS: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism. MAIN OUTCOMES AND MEASURES: De novo variants present only in the index case and not in unaffected family members. RESULTS: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway. CONCLUSIONS AND RELEVANCE: These data ...
In: Johnson , J O , Chia , R , Miller , D E , Li , R , Kumaran , R , Abramzon , Y , Alahmady , N , Renton , A E , Topp , S D , Gibbs , J R , Cookson , M R , Sabir , M S , Dalgard , C L , Troakes , C , Jones , A R , Shatunov , A , Iacoangeli , A , Al Khleifat , A , Ticozzi , N , Silani , V , Gellera , C , Blair , I P , Dobson-Stone , C , Kwok , J B , Bonkowski , E S , Palvadeau , R , Tienari , P J , Morrison , K E , Shaw , P J , Al-Chalabi , A , Brown , R H , Calvo , A , Mora , G , Al-Saif , H , Gotkine , M , Leigh , F , Chang , I J , Perlman , S J , Glass , I , Scott , A I , Shaw , C E , Basak , A N , Landers , J E , Chiò , A , Crawford , T O , Smith , B N , Traynor , B J , Smith , B N , Ticozzi , N , Fallini , C , Gkazi , A S , Topp , S D , Scotter , E L , Kenna , K P , Keagle , P , Tiloca , C , Vance , C , Troakes , C , Colombrita , C , King , A , Pensato , V , Castellotti , B , Baas , F , Ten Asbroek , A L M A , McKenna-Yasek , D , McLaughlin , R L , Polak , M , Asress , S , Esteban-Pérez , J , Stevic , Z , D'Alfonso , S , Mazzini , L , Comi , G P , Del Bo , R , Ceroni , M , Gagliardi , S , Querin , G , Bertolin , C , Van Rheenen , W , Rademakers , R , Van Blitterswijk , M , Lauria , G , Duga , S , Corti , S , Cereda , C , Corrado , L , Sorarù , G , Williams , K L , Nicholson , G A , Blair , I P , Leblond-Manry , C , Rouleau , G A , Hardiman , O , Morrison , K E , Veldink , J H , Van Den Berg , L H , Al-Chalabi , A , Pall , H , Shaw , P J , Turner , M R , Talbot , K , Taroni , F , García-Redondo , A , Wu , Z , Glass , J D , Gellera , C , Ratti , A , Brown , R H , Silani , V , Shaw , C E , Landers , J E , Dalgard , C L , Adeleye , A , Soltis , A R , Alba , C , Viollet , C , Bacikova , D , Hupalo , D N , Sukumar , G , Pollard , H B , Wilkerson , M D , Martinez , E M G , Abramzon , Y , Ahmed , S , Arepalli , S , Baloh , R H , Bowser , R , Brady , C B , Brice , A , Broach , J , Campbell , R H , Camu , W , Chia , R , Cooper-Knock , J , Ding , J , Drepper , C , Drory , V E , Dunckley , T L , Eicher , J D , England , B K , Faghri , F , Feldman , E , Floeter , M K , Fratta , P , Geiger , J T , Gerhard , G , Gibbs , J R , Gibson , S B , Glass , J D , Hardy , J , Harms , M B , Heiman-Patterson , T D , Hernandez , D G , Jansson , L , Kirby , J , Kowall , N W , Laaksovirta , H , Landeck , N , Landi , F , Le Ber , I , Lumbroso , S , Macgowan , D J L , Maragakis , N J , Mora , G , Mouzat , K , Murphy , N A , Myllykangas , L , Nalls , M A , Orrell , R W , Ostrow , L W , Pamphlett , R , Pickering-Brown , S , Pioro , E P , Pletnikova , O , Pliner , H A , Pulst , S M , Ravits , J M , Renton , A E , Rivera , A , Robberecht , W , Rogaeva , E , Rollinson , S , Rothstein , J D , Scholz , S W , Sendtner , M , Shaw , P J , Sidle , K C , Simmons , Z , Singleton , A B , Smith , N , Stone , D J , Tienari , P J , Troncoso , J C , Valori , M , Van Damme , P , Van Deerlin , V M , Van Den Bosch , L , Zinman , L , Landers , J E , Chiò , A , Traynor , B J , Angelocola , S M , Ausiello , F P , Barberis , M , Bartolomei , I , Battistini , S , Bersano , E , Bisogni , G , Borghero , G , Brunetti , M , Cabona , C , Calvo , A , Canale , F , Canosa , A , Cantisani , T A , Capasso , M , Caponnetto , C , Cardinali , P , Carrera , P , Casale , F , Chiò , A , Colletti , T , Conforti , F L , Conte , A , Conti , E , Corbo , M , Cuccu , S , Dalla Bella , E , D'Errico , E , Demarco , G , Dubbioso , R , Ferrarese , C , Ferraro , P M , Filippi , M , Fini , N , Floris , G , Fuda , G , Gallone , S , Gianferrari , G , Giannini , F , Grassano , M , Greco , L , Iazzolino , B , Introna , A , La Bella , V , Lattante , S , Lauria , G , Liguori , R , Logroscino , G , Logullo , F O , Lunetta , C , Mandich , P , Mandrioli , J , Manera , U , Manganelli , F , Marangi , G , Marinou , K , Marrosu , M G , Martinelli , I , Messina , S , Moglia , C , Mora , G , Mosca , L , Murru , M R , Origone , P , Passaniti , C , Petrelli , C , Petrucci , A , Pozzi , S , Pugliatti , M , Quattrini , A , Ricci , C , Riolo , G , Riva , N , Russo , M , Sabatelli , M , Salamone , P , Salivetto , M , Salvi , F , Santarelli , M , Sbaiz , L , Sideri , R , Simone , I , Simonini , C , Spataro , R , Tanel , R , Tedeschi , G , Ticca , A , Torriello , A , Tranquilli , S , Tremolizzo , L , Trojsi , F , Vasta , R , Vacchiano , V , Vita , G , Volanti , P , Zollino , M & Zucchi , E 2021 , ' Association of Variants in the SPTLC1 Gene with Juvenile Amyotrophic Lateral Sclerosis ' , JAMA neurology . https://doi.org/10.1001/jamaneurol.2021.2598
Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation. Objective: To identify the genetic variants associated with juvenile ALS. Design, Setting, and Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism. Main Outcomes and Measures: De novo variants present only in the index case and not in unaffected family members. Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway. Conclusions and Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.