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Progeroid laminopathy with restrictive dermopathy-like features caused by an isodisomic LMNA mutation p.R435C.

Starke S, Meinke P, Camozzi D, Mattioli E, Pfaeffle R, Siekmeyer M, Hirsch W, Horn LC, Paasch U, Mitter D, Lattanzi G, Wehnert M, Kiess W - Aging (Albany NY) (2013)

Bottom Line: A homozygousLMNA mutation c.1303C>T (p.R435C) was found by Sanger sequencing.Haplotyping revealed a partial uniparental disomy of chromosome 1 (1q21.3 to 1q23.1) including the LMNA gene.The follow-up of the complete clinical course in the patient combined with functional studies showed for the first time that a progressive loss of lamin A rather than abnormal accumulation of prelamin A species could be a pathophysiological mechanism in progeroid laminopathies, which leads to DNA repair deficiency accompanied by advancing tissue degeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Women and Child Health, Hospital for Children and Adolescents, Centre of Pediatric Research, University Hospital, University of Leipzig, Leipzig, Germany. Sven.Starke@medizin.uni‐leipzig.de

ABSTRACT
The clinical course of a female patient affected by a progeroid syndrome with Restrictive Dermopathy (RD)-like features was followed up. Besides missing hairiness, stagnating weight and growth, RD-like features including progressive skin swelling and solidification, acrocontractures, osteolysis and muscular hypotension were observed until the patient died at the age of 11 months. A homozygousLMNA mutation c.1303C>T (p.R435C) was found by Sanger sequencing. Haplotyping revealed a partial uniparental disomy of chromosome 1 (1q21.3 to 1q23.1) including the LMNA gene. In contrast to reported RD patients with LMNA mutations, LMNA p.R435C is not located at the cleavage site necessary for processing of prelamin A by ZMPSTE24 and leads to a distinct phenotype combining clinical features of Restrictive Dermopathy, Mandibuloacral Dysplasia and Hutchinson-Gilford Progeria. Functionally, LMNA p.R435C is associated with increasing DNA double strand breaks and decreased recruitment of P53 binding protein 1 (53BP1) to DNA-damage sites indicating delayed DNA repair. The follow-up of the complete clinical course in the patient combined with functional studies showed for the first time that a progressive loss of lamin A rather than abnormal accumulation of prelamin A species could be a pathophysiological mechanism in progeroid laminopathies, which leads to DNA repair deficiency accompanied by advancing tissue degeneration.

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53BP1 localization in cultured human normal fibroblasts transfected with either mCherry-tagged LMNA-p.R435C or mCherry-tagged wt- LMNA plasmids. (A) untreated or (B) treated with hydrogen peroxide (H2O2). 53BP1 was specifically labeled using a monoclonal antibody and revealed by FITC –conjugated anti-mouse IgG secondary antibody (green). (C) Quantitation of 53BP1 foci in H2O2 –treated cells. Means of three different counts performed in separate experiments are reported +/− standard deviation. The difference is statistically significant (p<0.05 by the Student's T-test).
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Figure 7: 53BP1 localization in cultured human normal fibroblasts transfected with either mCherry-tagged LMNA-p.R435C or mCherry-tagged wt- LMNA plasmids. (A) untreated or (B) treated with hydrogen peroxide (H2O2). 53BP1 was specifically labeled using a monoclonal antibody and revealed by FITC –conjugated anti-mouse IgG secondary antibody (green). (C) Quantitation of 53BP1 foci in H2O2 –treated cells. Means of three different counts performed in separate experiments are reported +/− standard deviation. The difference is statistically significant (p<0.05 by the Student's T-test).

Mentions: Since the staining with anti-gamma H2AX indicated significant DNA dsb in the patient's autopsy, we tested the response of 53BP1 protein following oxidative stress in a cultured cell model containing the recombinant mutant lamin A. Human normal fibroblasts were transfected with either tagged LMNA p.R435C or tagged wt LMNA plasmids. After treatment of the transfected cells with hydrogen peroxide, we observed multiple 53BP1 foci at DNA damage sites in nuclei expressing human wild-type LMNA, whereas in p.R435C-LMNA transfected nuclei a low amount of foci appeared at the same time of treatment (Fig.7). Thus, while LMNA p.R435C seems able to localize to its normal nuclear lamina region (mentioned above), its ability to recruit 53BP1 to damaged DNA sites appears to be impaired.


Progeroid laminopathy with restrictive dermopathy-like features caused by an isodisomic LMNA mutation p.R435C.

Starke S, Meinke P, Camozzi D, Mattioli E, Pfaeffle R, Siekmeyer M, Hirsch W, Horn LC, Paasch U, Mitter D, Lattanzi G, Wehnert M, Kiess W - Aging (Albany NY) (2013)

53BP1 localization in cultured human normal fibroblasts transfected with either mCherry-tagged LMNA-p.R435C or mCherry-tagged wt- LMNA plasmids. (A) untreated or (B) treated with hydrogen peroxide (H2O2). 53BP1 was specifically labeled using a monoclonal antibody and revealed by FITC –conjugated anti-mouse IgG secondary antibody (green). (C) Quantitation of 53BP1 foci in H2O2 –treated cells. Means of three different counts performed in separate experiments are reported +/− standard deviation. The difference is statistically significant (p<0.05 by the Student's T-test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824411&req=5

Figure 7: 53BP1 localization in cultured human normal fibroblasts transfected with either mCherry-tagged LMNA-p.R435C or mCherry-tagged wt- LMNA plasmids. (A) untreated or (B) treated with hydrogen peroxide (H2O2). 53BP1 was specifically labeled using a monoclonal antibody and revealed by FITC –conjugated anti-mouse IgG secondary antibody (green). (C) Quantitation of 53BP1 foci in H2O2 –treated cells. Means of three different counts performed in separate experiments are reported +/− standard deviation. The difference is statistically significant (p<0.05 by the Student's T-test).
Mentions: Since the staining with anti-gamma H2AX indicated significant DNA dsb in the patient's autopsy, we tested the response of 53BP1 protein following oxidative stress in a cultured cell model containing the recombinant mutant lamin A. Human normal fibroblasts were transfected with either tagged LMNA p.R435C or tagged wt LMNA plasmids. After treatment of the transfected cells with hydrogen peroxide, we observed multiple 53BP1 foci at DNA damage sites in nuclei expressing human wild-type LMNA, whereas in p.R435C-LMNA transfected nuclei a low amount of foci appeared at the same time of treatment (Fig.7). Thus, while LMNA p.R435C seems able to localize to its normal nuclear lamina region (mentioned above), its ability to recruit 53BP1 to damaged DNA sites appears to be impaired.

Bottom Line: A homozygousLMNA mutation c.1303C>T (p.R435C) was found by Sanger sequencing.Haplotyping revealed a partial uniparental disomy of chromosome 1 (1q21.3 to 1q23.1) including the LMNA gene.The follow-up of the complete clinical course in the patient combined with functional studies showed for the first time that a progressive loss of lamin A rather than abnormal accumulation of prelamin A species could be a pathophysiological mechanism in progeroid laminopathies, which leads to DNA repair deficiency accompanied by advancing tissue degeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Women and Child Health, Hospital for Children and Adolescents, Centre of Pediatric Research, University Hospital, University of Leipzig, Leipzig, Germany. Sven.Starke@medizin.uni‐leipzig.de

ABSTRACT
The clinical course of a female patient affected by a progeroid syndrome with Restrictive Dermopathy (RD)-like features was followed up. Besides missing hairiness, stagnating weight and growth, RD-like features including progressive skin swelling and solidification, acrocontractures, osteolysis and muscular hypotension were observed until the patient died at the age of 11 months. A homozygousLMNA mutation c.1303C>T (p.R435C) was found by Sanger sequencing. Haplotyping revealed a partial uniparental disomy of chromosome 1 (1q21.3 to 1q23.1) including the LMNA gene. In contrast to reported RD patients with LMNA mutations, LMNA p.R435C is not located at the cleavage site necessary for processing of prelamin A by ZMPSTE24 and leads to a distinct phenotype combining clinical features of Restrictive Dermopathy, Mandibuloacral Dysplasia and Hutchinson-Gilford Progeria. Functionally, LMNA p.R435C is associated with increasing DNA double strand breaks and decreased recruitment of P53 binding protein 1 (53BP1) to DNA-damage sites indicating delayed DNA repair. The follow-up of the complete clinical course in the patient combined with functional studies showed for the first time that a progressive loss of lamin A rather than abnormal accumulation of prelamin A species could be a pathophysiological mechanism in progeroid laminopathies, which leads to DNA repair deficiency accompanied by advancing tissue degeneration.

Show MeSH
Related in: MedlinePlus