Abstract
Background: The breadth of the clinical spectrum underlying Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is due to the extensive allelic heterogeneity in the X-linked PLP1 gene encoding myelin proteolipid protein (PLP). PLP1 mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients. Methods. Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for PLP1 gene duplications using real-time PCR. PLP1 gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial PLP1 gene mutation was determined as well as 15/24 potential carrier mothers of the PLP1 duplication. Results and Conclusions. PLP1 gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic PLP1 mutations were found in the remaining 14 patients. Of the 14 different intragenic lesions, 11 were novel; these included one nonsense and 7 missense mutations, a 657-bp deletion, a microdeletion and a microduplication. The functional significance of the novel PLP1 missense mutations, all occurring at evolutionarily conserved residues, was analysed by the MutPred tool whereas their potential effect on splicing was ascertained using the Skippy algorithm and a neural network. Although MutPred predicted that all 7 novel missense mutations would be likely to be deleterious, in silico analysis indicated that four of them (p.Leu146Val, p.Leu159Pro, p.Thr230Ile, p.Ala247Asp) might cause exon skipping by altering exonic splicing elements. These predictions were then investigated in vitro for both p.Leu146Val and p.Thr230Ile by means of RNA or minigene studies and were subsequently confirmed in the case of p.Leu146Val. Peripheral neuropathy was noted in four patients harbouring intragenic mutations that altered RNA processing, but was absent from all PLP1-duplication patients. Unprecedentedly, family studies revealed the de novo occurrence of the PLP1 duplication at a frequency of 20%.
| Original language | English |
|---|---|
| Article number | 40 |
| Journal | Orphanet Journal of Rare Diseases |
| Volume | 6 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2011 |
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ASJC Scopus subject areas
- Medicine(all)
- Genetics(clinical)
- Pharmacology (medical)
Cite this
Molecular Genetic Analysis of the PLP1 Gene in 38 Families with PLP1-related disorders : Identification and Functional Characterization of 11 Novel PLP1 Mutations. / Grossi, Serena; Regis, Stefano; Biancheri, Roberta; Mort, Matthew; Lualdi, Susanna; Bertini, Enrico; Uziel, Graziella; Boespflug-Tanguy, Odile; Simonati, Alessandro; Corsolini, Fabio; Demir, Ercan; Marchiani, Valentina; Percesepe, Antonio; Stanzial, Franco; Rossi, Andrea; Vaurs-Barrière, Catherine; Cooper, David N.; Filocamo, Mirella.
In: Orphanet Journal of Rare Diseases, Vol. 6, No. 1, 40, 2011.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Molecular Genetic Analysis of the PLP1 Gene in 38 Families with PLP1-related disorders
T2 - Identification and Functional Characterization of 11 Novel PLP1 Mutations
AU - Grossi, Serena
AU - Regis, Stefano
AU - Biancheri, Roberta
AU - Mort, Matthew
AU - Lualdi, Susanna
AU - Bertini, Enrico
AU - Uziel, Graziella
AU - Boespflug-Tanguy, Odile
AU - Simonati, Alessandro
AU - Corsolini, Fabio
AU - Demir, Ercan
AU - Marchiani, Valentina
AU - Percesepe, Antonio
AU - Stanzial, Franco
AU - Rossi, Andrea
AU - Vaurs-Barrière, Catherine
AU - Cooper, David N.
AU - Filocamo, Mirella
PY - 2011
Y1 - 2011
N2 - Background: The breadth of the clinical spectrum underlying Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is due to the extensive allelic heterogeneity in the X-linked PLP1 gene encoding myelin proteolipid protein (PLP). PLP1 mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients. Methods. Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for PLP1 gene duplications using real-time PCR. PLP1 gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial PLP1 gene mutation was determined as well as 15/24 potential carrier mothers of the PLP1 duplication. Results and Conclusions. PLP1 gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic PLP1 mutations were found in the remaining 14 patients. Of the 14 different intragenic lesions, 11 were novel; these included one nonsense and 7 missense mutations, a 657-bp deletion, a microdeletion and a microduplication. The functional significance of the novel PLP1 missense mutations, all occurring at evolutionarily conserved residues, was analysed by the MutPred tool whereas their potential effect on splicing was ascertained using the Skippy algorithm and a neural network. Although MutPred predicted that all 7 novel missense mutations would be likely to be deleterious, in silico analysis indicated that four of them (p.Leu146Val, p.Leu159Pro, p.Thr230Ile, p.Ala247Asp) might cause exon skipping by altering exonic splicing elements. These predictions were then investigated in vitro for both p.Leu146Val and p.Thr230Ile by means of RNA or minigene studies and were subsequently confirmed in the case of p.Leu146Val. Peripheral neuropathy was noted in four patients harbouring intragenic mutations that altered RNA processing, but was absent from all PLP1-duplication patients. Unprecedentedly, family studies revealed the de novo occurrence of the PLP1 duplication at a frequency of 20%.
AB - Background: The breadth of the clinical spectrum underlying Pelizaeus-Merzbacher disease and spastic paraplegia type 2 is due to the extensive allelic heterogeneity in the X-linked PLP1 gene encoding myelin proteolipid protein (PLP). PLP1 mutations range from gene duplications of variable size found in 60-70% of patients to intragenic lesions present in 15-20% of patients. Methods. Forty-eight male patients from 38 unrelated families with a PLP1-related disorder were studied. All DNA samples were screened for PLP1 gene duplications using real-time PCR. PLP1 gene sequencing analysis was performed on patients negative for the duplication. The mutational status of all 14 potential carrier mothers of the familial PLP1 gene mutation was determined as well as 15/24 potential carrier mothers of the PLP1 duplication. Results and Conclusions. PLP1 gene duplications were identified in 24 of the unrelated patients whereas a variety of intragenic PLP1 mutations were found in the remaining 14 patients. Of the 14 different intragenic lesions, 11 were novel; these included one nonsense and 7 missense mutations, a 657-bp deletion, a microdeletion and a microduplication. The functional significance of the novel PLP1 missense mutations, all occurring at evolutionarily conserved residues, was analysed by the MutPred tool whereas their potential effect on splicing was ascertained using the Skippy algorithm and a neural network. Although MutPred predicted that all 7 novel missense mutations would be likely to be deleterious, in silico analysis indicated that four of them (p.Leu146Val, p.Leu159Pro, p.Thr230Ile, p.Ala247Asp) might cause exon skipping by altering exonic splicing elements. These predictions were then investigated in vitro for both p.Leu146Val and p.Thr230Ile by means of RNA or minigene studies and were subsequently confirmed in the case of p.Leu146Val. Peripheral neuropathy was noted in four patients harbouring intragenic mutations that altered RNA processing, but was absent from all PLP1-duplication patients. Unprecedentedly, family studies revealed the de novo occurrence of the PLP1 duplication at a frequency of 20%.
UR - http://www.scopus.com/inward/record.url?scp=79959230718&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959230718&partnerID=8YFLogxK
U2 - 10.1186/1750-1172-6-40
DO - 10.1186/1750-1172-6-40
M3 - Article
C2 - 21679407
AN - SCOPUS:79959230718
VL - 6
JO - Orphanet Journal of Rare Diseases
JF - Orphanet Journal of Rare Diseases
SN - 1750-1172
IS - 1
M1 - 40
ER -