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Franco E, Scanga HL, Nischal KK. Variable phenotype of secondary congenital corneal opacities associated with microphthalmia with linear skin defects syndrome. Am J Med Genet A 2023; 191:586-591. [PMID: 36369709 DOI: 10.1002/ajmg.a.63043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/15/2022]
Abstract
To describe the anterior segment (AS) findings in patients with microphthalmia with linear skin defects syndrome (MLS), also known as microphthalmia, dermal aplasia, and sclerocornea (MIDAS). A retrospective chart review was conducted to identify patients with a diagnosis of MLS syndrome seen at UPMC Children's Hospital of Pittsburgh. Ophthalmic examination, high-frequency ultrasound, AS optical coherence tomography, and molecular testing were reviewed. Five female patients (10 eyes) were identified. One eye was anophthalmic, one was in a status post penetrating keratoplasty, and eight eyes presented with congenital corneal opacity (CCO). Of these, one showed a normal lens and a very small faint CCO; five showed congenital aphakia and characteristic silvery appearance of the cornea with vascularization; and two showed irido-corneal adhesions in association with normal or abnormal lens and localized avascular CCO. Genetic testing was performed and revealed involvement of HCCS in four patients. In MLS patients, kerato-irido-lenticular dysgenesis can be associated with secondary CCO. It is important to distinguish these CCO from sclerocornea, in order to refine the appropriate management and counseling the parents about the prognosis.
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Affiliation(s)
- Elena Franco
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Translational Medicine, University of Ferrara, Ferrara, Italy.,Istituto Internazionale per la Ricerca e Formazione in Oftalmologia (IRFO), Forlì, Italy
| | - Hannah L Scanga
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ken K Nischal
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Blackout in the powerhouse: clinical phenotypes associated with defects in the assembly of OXPHOS complexes and the mitoribosome. Biochem J 2021; 477:4085-4132. [PMID: 33151299 PMCID: PMC7657662 DOI: 10.1042/bcj20190767] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria produce the bulk of the energy used by almost all eukaryotic cells through oxidative phosphorylation (OXPHOS) which occurs on the four complexes of the respiratory chain and the F1–F0 ATPase. Mitochondrial diseases are a heterogenous group of conditions affecting OXPHOS, either directly through mutation of genes encoding subunits of OXPHOS complexes, or indirectly through mutations in genes encoding proteins supporting this process. These include proteins that promote assembly of the OXPHOS complexes, the post-translational modification of subunits, insertion of cofactors or indeed subunit synthesis. The latter is important for all 13 of the proteins encoded by human mitochondrial DNA, which are synthesised on mitochondrial ribosomes. Together the five OXPHOS complexes and the mitochondrial ribosome are comprised of more than 160 subunits and many more proteins support their biogenesis. Mutations in both nuclear and mitochondrial genes encoding these proteins have been reported to cause mitochondrial disease, many leading to defective complex assembly with the severity of the assembly defect reflecting the severity of the disease. This review aims to act as an interface between the clinical and basic research underpinning our knowledge of OXPHOS complex and ribosome assembly, and the dysfunction of this process in mitochondrial disease.
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van Rahden V, Fernandez-Vizarra E, Alawi M, Brand K, Fellmann F, Horn D, Zeviani M, Kutsche K. Mutations in NDUFB11, encoding a complex I component of the mitochondrial respiratory chain, cause microphthalmia with linear skin defects syndrome. Am J Hum Genet 2015; 96:640-50. [PMID: 25772934 DOI: 10.1016/j.ajhg.2015.02.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/02/2015] [Indexed: 01/07/2023] Open
Abstract
Microphthalmia with linear skin defects (MLS) syndrome is an X-linked male-lethal disorder also known as MIDAS (microphthalmia, dermal aplasia, and sclerocornea). Additional clinical features include neurological and cardiac abnormalities. MLS syndrome is genetically heterogeneous given that heterozygous mutations in HCCS or COX7B have been identified in MLS-affected females. Both genes encode proteins involved in the structure and function of complexes III and IV, which form the terminal segment of the mitochondrial respiratory chain (MRC). However, not all individuals with MLS syndrome carry a mutation in either HCCS or COX7B. The majority of MLS-affected females have severe skewing of X chromosome inactivation, suggesting that mutations in HCCS, COX7B, and other as-yet-unidentified X-linked gene(s) cause selective loss of cells in which the mutated X chromosome is active. By applying whole-exome sequencing and filtering for X-chromosomal variants, we identified a de novo nonsense mutation in NDUFB11 (Xp11.23) in one female individual and a heterozygous 1-bp deletion in a second individual, her asymptomatic mother, and an affected aborted fetus of the subject's mother. NDUFB11 encodes one of 30 poorly characterized supernumerary subunits of NADH:ubiquinone oxidoreductase, known as complex I (cI), the first and largest enzyme of the MRC. By shRNA-mediated NDUFB11 knockdown in HeLa cells, we demonstrate that NDUFB11 is essential for cI assembly and activity as well as cell growth and survival. These results demonstrate that X-linked genetic defects leading to the complete inactivation of complex I, III, or IV underlie MLS syndrome. Our data reveal an unexpected role of cI dysfunction in a developmental phenotype, further underscoring the existence of a group of mitochondrial diseases associated with neurocutaneous manifestations.
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Abstract
INTRODUCTION In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. SOURCES OF DATA In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. AREAS OF AGREEMENT The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. AREAS OF CONTROVERSY The exact mechanisms which govern the inheritance of mtDNA are hotly debated. GROWING POINTS Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease.
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Affiliation(s)
| | - Gavin Hudson
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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Indrieri A, van Rahden V, Tiranti V, Morleo M, Iaconis D, Tammaro R, D’Amato I, Conte I, Maystadt I, Demuth S, Zvulunov A, Kutsche K, Zeviani M, Franco B. Mutations in COX7B cause microphthalmia with linear skin lesions, an unconventional mitochondrial disease. Am J Hum Genet 2012; 91:942-9. [PMID: 23122588 PMCID: PMC3487127 DOI: 10.1016/j.ajhg.2012.09.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/31/2012] [Accepted: 09/28/2012] [Indexed: 11/16/2022] Open
Abstract
Microphthalmia with linear skin lesions (MLS) is an X-linked dominant male-lethal disorder associated with mutations in holocytochrome c-type synthase (HCCS), which encodes a crucial player of the mitochondrial respiratory chain (MRC). Unlike other mitochondrial diseases, MLS is characterized by a well-recognizable neurodevelopmental phenotype. Interestingly, not all clinically diagnosed MLS cases have mutations in HCCS, thus suggesting genetic heterogeneity for this disorder. Among the possible candidates, we analyzed the X-linked COX7B and found deleterious de novo mutations in two simplex cases and a nonsense mutation, which segregates with the disease, in a familial case. COX7B encodes a poorly characterized structural subunit of cytochrome c oxidase (COX), the MRC complex IV. We demonstrated that COX7B is indispensable for COX assembly, COX activity, and mitochondrial respiration. Downregulation of the COX7B ortholog (cox7B) in medaka (Oryzias latipes) resulted in microcephaly and microphthalmia that recapitulated the MLS phenotype and demonstrated an essential function of complex IV activity in vertebrate CNS development. Our results indicate an evolutionary conserved role of the MRC complexes III and IV for the proper development of the CNS in vertebrates and uncover a group of mitochondrial diseases hallmarked by a developmental phenotype.
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Affiliation(s)
- Alessia Indrieri
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
| | | | - Valeria Tiranti
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology, 20126 Milan, Italy
| | - Manuela Morleo
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
| | - Daniela Iaconis
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
| | - Roberta Tammaro
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
| | - Ilaria D’Amato
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology, 20126 Milan, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
| | - Isabelle Maystadt
- Centre de Genetique Humaine, Institut de Pathologie et de Genetique, 6041 Gosselies (Charleroi), Belgium
| | | | - Alex Zvulunov
- Schneider Children’s Medical Center of Israel, Faculty of Health Sciences, Medical School for International Health, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
| | - Kerstin Kutsche
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Massimo Zeviani
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology, 20126 Milan, Italy
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine, 80131 Naples, Italy
- Medical Genetics Services, Department of Pediatrics, Federico II University, 80131 Naples, Italy
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Affiliation(s)
- Jonathan Zumwalt
- Department of Pediatric Dermatology, Loma Linda University, Loma Linda, California 92350, USA.
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Theisen A, Shaffer LG. Disorders caused by chromosome abnormalities. APPLICATION OF CLINICAL GENETICS 2010; 3:159-74. [PMID: 23776360 PMCID: PMC3681172 DOI: 10.2147/tacg.s8884] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many human genetic disorders result from unbalanced chromosome abnormalities, in which there is a net gain or loss of genetic material. Such imbalances often disrupt large numbers of dosage-sensitive, developmentally important genes and result in specific and complex phenotypes. Alternately, some chromosomal syndromes may be caused by a deletion or duplication of a single gene with pleiotropic effects. Traditionally, chromosome abnormalities were identified by visual inspection of the chromosomes under a microscope. The use of molecular cytogenetic technologies, such as fluorescence in situ hybridization and microarrays, has allowed for the identification of cryptic or submicroscopic imbalances, which are not visible under the light microscope. Microarrays have allowed for the identification of numerous new syndromes through a genotype-first approach in which patients with the same or overlapping genomic alterations are identified and then the phenotypes are described. Because many chromosomal alterations are large and encompass numerous genes, the ascertainment of individuals with overlapping deletions and varying clinical features may allow researchers to narrow the region in which to search for candidate genes.
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Kashork CD, Theisen A, Shaffer LG. Diagnosis of cryptic chromosomal syndromes by fluorescence in situ hybridization (FISH). CURRENT PROTOCOLS IN HUMAN GENETICS 2010; Chapter 8:Unit 8.10.1-20. [PMID: 20891031 DOI: 10.1002/0471142905.hg0810s67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This unit describes the various methods by which cytogeneticists detect chromosome abnormalities. The unit offers guidance for detecting such abnormalities with fluorescence in situ hybridization (FISH), as well as the benefits, limitations, and other applications of FISH.
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Sugar J, Wadia HP. Congenital Corneal Anomalies. Ophthalmology 2009. [DOI: 10.1016/b978-0-323-04332-8.00027-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Sharma VM, Ruiz de Luzuriaga AM, Waggoner D, Greenwald M, Stein SL. Microphthalmia with linear skin defects: a case report and review. Pediatr Dermatol 2008; 25:548-52. [PMID: 18950397 DOI: 10.1111/j.1525-1470.2008.00724.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microphthalmia with linear skin defects syndrome is an X-linked dominant disorder characterized by microphthalmia and other ocular anomalies as well as linear, jagged skin defects typically involving the scalp, face, neck, and upper trunk. Other associated characteristics include short stature, developmental delay, congenital heart defects, diaphragmatic hernia, agenesis of the corpus callosum, anencephaly, hydrocephalus, and seizures. Microphthalmia with linear skin defects syndrome is now known to be associated with a deletion of the X chromosome at Xp22. This is an area that has been found to include the HCCS gene, which encodes a holocytochrome c-type synthase believed to be critical in the regulation of apoptosis. We present a patient with classic clinical and genetic findings of MLS syndrome and discuss the primary characteristics and management of this disorder.
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Affiliation(s)
- Vishakha M Sharma
- Department of Medicine, Section of Dermatology, University of Chicago, Chicago, Illinois, USA.
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Abstract
PURPOSE To describe the histopathology of the cornea in microphthalmia with linear streaks (MLS) syndrome. METHODS Two patients with MLS syndrome underwent penetrating keratoplasty. This study describes the histopathology and investigates immunophenotype of the corneal extracellular matrix by using keratan sulfate and collagen type III antibodies. RESULTS Clinical examination revealed bilateral sclerocornea and characteristic skin changes. By light microscopy, central corneal stroma in both patients showed vascularization and irregular thick collagen lamellae typical of sclerocornea. In addition, corneal thinning, anterior synechiae, and the absence of the Descemet membrane were noted, which was suggestive of Peters anomaly. Diffuse and intense anti-keratan sulfate staining and minimal anti-collagen type III stromal staining were seen in both corneal buttons. CONCLUSIONS The cornea in MLS may clinically resemble sclerocornea. Histologic features resemble those previously described in sclerocornea and also seen in anterior segment dysgeneses. Keratan sulfate and collagen type III labeling suggests that the corneal extracellular matrix resembled cornea and not sclera.
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Wimplinger I, Rauch A, Orth U, Schwarzer U, Trautmann U, Kutsche K. Mother and daughter with a terminal Xp deletion: implication of chromosomal mosaicism and X-inactivation in the high clinical variability of the microphthalmia with linear skin defects (MLS) syndrome. Eur J Med Genet 2007; 50:421-31. [PMID: 17845869 DOI: 10.1016/j.ejmg.2007.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 07/09/2007] [Indexed: 10/23/2022]
Abstract
The microphthalmia with linear skin defects (MLS or MIDAS) syndrome is a rare X-linked dominant inherited disorder with male lethality, associated with segmental aneuploidy of the Xp22.2 region in most of the cases. However, we recently described heterozygous sequence alterations in a single gene, HCCS, in females with MLS. Beside the classical MLS phenotype, occasional features such as sclerocornea, agenesis of the corpus callosum, and congenital heart defects can occur. Although the majority of cases are sporadic, mother-to-daughter transmission has been observed and a high intra- and interfamilial phenotypic variability exists. We describe an asymptomatic mother and her daughter presenting with the typical features of MLS syndrome. By cytogenetic analysis both females were found to have a terminal Xp deletion with the breakpoint in Xp22.2, mapping near to or within the MSL3L1 gene which is located centromeric to HCCS. FISH analysis revealed that the mother is a mosaic with 45,X(11)/46,X,del(X)(p22.2)(89), while in all cells of the MLS-affected daughter a hybridization pattern consistent with a 46,X,del(X)(p22.2) karyotype was detected. By haplotype analysis we identified the paternal X chromosome of the mother to carry the terminal Xp deletion. X-inactivation studies showed a completely skewed pattern in mother and daughter with the deleted X chromosome to be preferentially inactivated in their peripheral blood cells. We suggest that both chromosomal mosaicism as well as functional X chromosome mosaicism could contribute to the lack of any typical MLS feature in individuals with a heterozygous MLS-associated mutation. The 45,X cell population, that most likely is also present in other tissues of the mother, might have protected her from developing MLS. Nonetheless, a non-random X-inactivation pattern in favor of activity of the wild-type X chromosome in the early blastocyte could also account for the apparent lack of any disease sign in this female.
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Affiliation(s)
- Isabella Wimplinger
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Campus Forschung, Gebäude 146, Martinistrasse 52, D-20246 Hamburg, Germany
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Cain CC, Saul D, Attanasio L, Oehler E, Hamosh A, Blakemore K, Stetten G. Microphthalmia with linear skin defects (MLS) syndrome evaluated by prenatal karyotyping, FISH and array comparative genomic hybridization. Prenat Diagn 2007; 27:373-9. [PMID: 17286317 DOI: 10.1002/pd.1674] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To explore the utility of comparative genomic hybridization to BAC arrays (array CGH) for prenatal diagnosis of microphthalmia and linear skin defects syndrome. METHODS We used karyotype analysis, FISH and array CGH to investigate an X;Y translocation. Replication studies were done on cultured amniocytes and lymphoblasts. RESULTS We describe a severe case of MLS syndrome that presented prenatally with multiple anomalies including cystic hygroma, microphthalmia, intrauterine growth restriction and a complex congenital heart defect. Cytogenetic analysis of amniocytes revealed an unbalanced de novo translocation between chromosomes X and Y [karyotype 46,X,der(X)t(X;Y)(p22.3;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2 (Tuple1 x 2)]. MLS diagnosis was made at birth and the prenatal karyotype was confirmed. Replication studies showed the derivative X chromosome was the inactive X. Array CGH confirmed the X and Y imbalances seen in the karyotype and also showed twelve BACs in the MLS region were deleted as a result of the translocation. FISH with BAC clones verified the array findings and placed the X breakpoint in Xp22.2, resulting in the amended karyotype, 46,X,der(X)t(X;Y)(p22.2;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2(Tuple1 x 2) arr cgh Xp22.33p22.2(LLNOYCO3M15D10 -->GS1-590J6)x 1,Yq11.222q23(RP11-20H21-->RP11-79J10)x 1. CONCLUSION The sensitivity of array CGH was valuable in detecting monosomy of the MLS critical region. Array CGH should be considered for the prenatal diagnosis of this syndrome.
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Affiliation(s)
- Colyn Cargile Cain
- Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Wimplinger I, Morleo M, Rosenberger G, Iaconis D, Orth U, Meinecke P, Lerer I, Ballabio A, Gal A, Franco B, Kutsche K. Mutations of the mitochondrial holocytochrome c-type synthase in X-linked dominant microphthalmia with linear skin defects syndrome. Am J Hum Genet 2006; 79:878-89. [PMID: 17033964 PMCID: PMC1698567 DOI: 10.1086/508474] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 08/15/2006] [Indexed: 12/23/2022] Open
Abstract
The microphthalmia with linear skin defects syndrome (MLS, or MIDAS) is an X-linked dominant male-lethal disorder almost invariably associated with segmental monosomy of the Xp22 region. In two female patients, from two families, with MLS and a normal karyotype, we identified heterozygous de novo point mutations--a missense mutation (p.R217C) and a nonsense mutation (p.R197X)--in the HCCS gene. HCCS encodes the mitochondrial holocytochrome c-type synthase that functions as heme lyase by covalently adding the prosthetic heme group to both apocytochrome c and c(1). We investigated a third family, displaying phenotypic variability, in which the mother and two of her daughters carry an 8.6-kb submicroscopic deletion encompassing part of the HCCS gene. Functional analysis demonstrates that both mutant proteins (R217C and Delta 197-268) were unable to complement a Saccharomyces cerevisiae mutant deficient for the HCCS orthologue Cyc3p, in contrast to wild-type HCCS. Moreover, ectopically expressed HCCS wild-type and the R217C mutant protein are targeted to mitochondria in CHO-K1 cells, whereas the C-terminal-truncated Delta 197-268 mutant failed to be sorted to mitochondria. Cytochrome c, the final product of holocytochrome c-type synthase activity, is implicated in both oxidative phosphorylation (OXPHOS) and apoptosis. We hypothesize that the inability of HCCS-deficient cells to undergo cytochrome c-mediated apoptosis may push cell death toward necrosis that gives rise to severe deterioration of the affected tissues. In summary, we suggest that disturbance of both OXPHOS and the balance between apoptosis and necrosis, as well as the X-inactivation pattern, may contribute to the variable phenotype observed in patients with MLS.
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Affiliation(s)
- Isabella Wimplinger
- Institut fur Humangenetik, Universitatsklinikum Hamburg-Eppendorf, Butenfeld 42, Hamburg, Germany
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Morleo M, Pramparo T, Perone L, Gregato G, Le Caignec C, Mueller RF, Ogata T, Raas-Rothschild A, de Blois MC, Wilson LC, Zaidman G, Zuffardi O, Ballabio A, Franco B. Microphthalmia with linear skin defects (MLS) syndrome: Clinical, cytogenetic, and molecular characterization of 11 cases. Am J Med Genet A 2005; 137:190-8. [PMID: 16059943 DOI: 10.1002/ajmg.a.30864] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The microphthalmia with linear skin defects (MLS) syndrome (MIM 309801) is a severe and rare developmental disorder, which is inherited as an X-linked dominant trait with male lethality. In the vast majority of patients, this syndrome is associated with terminal deletion of the Xp22.3 region. Thirty-five cases have been described to date in the literature since the first description of the syndrome in the early 1990s. We now report on the clinical, cytogenetic, and molecular characterization of 11 patients, 7 of whom have not been described previously. Seven of these patients have chromosomal abnormalities of the short arm of the X-chromosome, which were characterized and defined by fluorescence in situ hybridization (FISH) analysis. Intriguingly, one of the patients displays an interstitial Xp22.3 deletion, which to the best of our knowledge is the first reported for this condition. Finally we report on the identification and molecular characterization of four cases with clinical features of MLS but apparently normal karyotypes, verified by FISH analysis using genomic clones spanning the MLS minimal critical region, and with genome-wide analysis using a 1 Mb resolution BAC microarray. These patients made it possible to undertake mutation screening of candidate genes and may prove critical for the identification of the gene responsible for this challenging and intriguing genetic disease.
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Affiliation(s)
- Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), Via Pietro Castellino 111, 80131 Naples, Italy
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Kutsche K, Werner W, Bartsch O, von der Wense A, Meinecke P, Gal A. Microphthalmia with linear skin defects syndrome (MLS): a male with a mosaic paracentric inversion of Xp. Cytogenet Genome Res 2004; 99:297-302. [PMID: 12900578 DOI: 10.1159/000071607] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2002] [Accepted: 12/20/2002] [Indexed: 11/19/2022] Open
Abstract
The microphthalmia with linear skin defects syndrome (MLS) is an X-linked dominant disorder with male lethality. In the majority of the patients reported, the MLS syndrome is caused by segmental monosomy of the Xp22.3 region. To date, five male patients with MLS and 46,XX karyotype ("XX males") have been described. Here we report on the first male case with MLS and an XY complement. The patient showed agenesis of the corpus callosum, histiocytoid cardiomyopathy, and lactic acidosis but no microphthalmia, and carried a mosaic subtle inversion of the short arm of the X chromosome in 15% of his peripheral blood lymphocytes, 46,Y,inv(X)(p22.13 approximately 22.2p22.32 approximately 22.33)[49]/46,XY[271]. By fluorescence IN SITU hybridization (FISH), we showed that YAC 225H10 spans the breakpoint in Xp22.3. End-sequencing and database analysis revealed a YAC insert of at least 416 kb containing the genes HCCS and AMELX, and exons 2-16 of ARHGAP6. Molecular cytogenetic data suggest that the Xp22.3 inversion breakpoint is located in intron 1 of ARHGAP6, the gene encoding the Rho GTPase activating protein 6. Future molecular studies in karyotypically normal female MLS patients to detect submicroscopic rearrangements including the ARHGAP6 gene as well as mutation screening of ARHGAP6 in patients with no obvious chromosomal rearrangements will clarify the role of this gene in MLS syndrome.
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Affiliation(s)
- K Kutsche
- Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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Kherbaoui-Redouani L, Eschard C, Bednarek N, Morville P, Bednare N. [Cutaneous aplasia, non compaction of the left ventricle and severe cardiac arrhythmia: a new case of MLS syndrome (microphtalmia with linear skin defects)]. Arch Pediatr 2003; 10:224-6. [PMID: 12829336 DOI: 10.1016/s0929-693x(03)00014-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A female neonate presented with cutaneous aplasia located to the face and the neck associated with a non compaction of the left ventricle leading to the diagnosis of MLS syndrome (microphtalmia with linear skin defects). The follow-up was complicated by life-threatening cardiac arrhythmia underlying prevention by an early diagnosis and adequate care. MLS syndrome and non compaction of myocardium are both located on X chromosome.
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Affiliation(s)
- L Kherbaoui-Redouani
- Service de néonatologie et réanimation infantile, American Memorial Hospital, hôpital d'enfants, 47, rue Cognacq-Jay, 52092 cedex, Reims, France
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Zannolli R, Mostardini R, Pucci L, Sorrentino L, Biagioli M, Perotti R, Guarna M, Hadjistilianou T, Zerega G, Pierluigi M, Franco B, D'Ambrosio A, Morgese G. Corpus callosum agenesis, multiple cysts, skin defects, and subtle ocular abnormalities with a de novo mutation [45,XX,der(5), t(5;;14) (pter;q11.2)]. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 102:29-35. [PMID: 11471169 DOI: 10.1002/1096-8628(20010722)102:1<29::aid-ajmg1367>3.0.co;2-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report on a 2-year-old girl with a de novo mutation [45,XX,der(5),t(5;14) (pter;q11.2)] with corpus callosum agenesis, multiple cysts (cerebral and cardiac), subtle eye abnormalities, and at least two different skin defects, strongly indicating neuroectodermal involvement, as a neuromuscular choristoma (hamartoma) and an eccrine hamartoma. Fluorescent in situ hybridization with different single-locus probes showed that chromosome 5 has a very small deletion, confined to a region composed of repetitive sequences. By contrast, the long (q) arm of chromosome 14 seems to be much more involved in the rearrangement, with partial monosomy spanning from the centromere to the D14S72 and D14S261 loci. The extent of the deleted region of chromosome 14 is approximately 16 cM. To our knowledge, this is the smallest reported deletion involving the chromosome 14q11.2 region to be associated with a developmental disorder resulting in variable eye, skin, and brain anomalies. We suggest that a new syndrome, mimicking in some ways the MLS phenotype, is caused by a deletion in the chromosome 14q11.2 region.
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Affiliation(s)
- R Zannolli
- Department of Pediatrics, University of Siena, Italy.
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