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Khan S, Ansar M, Khan AK, Shah K, Muhammad N, Shahzad S, Nickerson DA, Bamshad MJ, Santos-Cortez RLP, Leal SM, Ahmad W. A homozygous missense mutation in SLC25A16 associated with autosomal recessive isolated fingernail dysplasia in a Pakistani family. Br J Dermatol 2017; 178:556-558. [PMID: 28504827 DOI: 10.1111/bjd.15661] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Lebeko K, Sloan-Heggen CM, Noubiap JJN, Dandara C, Kolbe DL, Ephraim SS, Booth KT, Azaiez H, Santos-Cortez RLP, Leal SM, Smith RJH, Wonkam A. Targeted genomic enrichment and massively parallel sequencing identifies novel nonsyndromic hearing impairment pathogenic variants in Cameroonian families. Clin Genet 2016; 90:288-90. [PMID: 27246798 DOI: 10.1111/cge.12799] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/19/2016] [Accepted: 05/01/2016] [Indexed: 01/22/2023]
Abstract
In sub-Saharan Africa GJB2-related nonsyndromic hearing impairment (NSHI) is rare. Ten Cameroonian families was studied using a platform (OtoSCOPE®) with 116 genes. In seven of 10 families (70%), 12 pathogenic variants were identified in six genes. Five of the 12 (41.6%) variants are novel. These results confirm the efficiency of comprehensive genetic testing in defining the causes of NSHI in sub-Saharan Africa.
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Regalado ES, Guo DC, Santos-Cortez RLP, Hostetler E, Bensend TA, Pannu H, Estrera A, Safi H, Mitchell AL, Evans JP, Leal SM, Bamshad M, Shendure J, Nickerson DA, Milewicz DM. Pathogenic FBN1 variants in familial thoracic aortic aneurysms and dissections. Clin Genet 2016; 89:719-23. [PMID: 26621581 DOI: 10.1111/cge.12702] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 11/26/2022]
Abstract
Marfan syndrome (MFS) due to mutations in FBN1 is a known cause of thoracic aortic aneurysms and acute aortic dissections (TAAD) associated with pleiotropic manifestations. Genetic predisposition to TAAD can also be inherited in families in the absence of syndromic features, termed familial TAAD (FTAAD), and several causative genes have been identified to date. FBN1 mutations can also be identified in FTAAD families, but the frequency of these mutations has not been established. We performed exome sequencing of 183 FTAAD families and identified pathogenic FBN1 variants in five (2.7%) of these families. We also identified eight additional FBN1 rare variants that could not be unequivocally classified as disease-causing in six families. FBN1 sequencing should be considered in individuals with FTAAD even without significant systemic features of MFS.
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Ahmad F, Ansar M, Mehmood S, Izoduwa A, Lee K, Nasir A, Abrar M, Mehmood S, Ullah A, Aziz A, Smith JD, Shendure J, Bamshad MJ, Nicekrson DA, Santos-Cortez RLP, Leal SM, Ahmad W. A novel missense variant in the PNPLA1 gene underlies congenital ichthyosis in three consanguineous families. J Eur Acad Dermatol Venereol 2015; 30:e210-e213. [PMID: 26691440 DOI: 10.1111/jdv.13540] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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MacArthur DG, Manolio TA, Dimmock DP, Rehm HL, Shendure J, Abecasis GR, Adams DR, Altman RB, Antonarakis SE, Ashley EA, Barrett JC, Biesecker LG, Conrad DF, Cooper GM, Cox NJ, Daly MJ, Gerstein MB, Goldstein DB, Hirschhorn JN, Leal SM, Pennacchio LA, Stamatoyannopoulos JA, Sunyaev SR, Valle D, Voight BF, Winckler W, Gunter C. Guidelines for investigating causality of sequence variants in human disease. Nature 2014; 508:469-76. [PMID: 24759409 PMCID: PMC4180223 DOI: 10.1038/nature13127] [Citation(s) in RCA: 940] [Impact Index Per Article: 94.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 02/05/2014] [Indexed: 11/26/2022]
Abstract
The discovery of rare genetic variants is accelerating, and clear guidelines for distinguishing disease-causing sequence variants from the many potentially functional variants present in any human genome are urgently needed. Without rigorous standards we risk an acceleration of false-positive reports of causality, which would impede the translation of genomic research findings into the clinical diagnostic setting and hinder biological understanding of disease. Here we discuss the key challenges of assessing sequence variants in human disease, integrating both gene-level and variant-level support for causality. We propose guidelines for summarizing confidence in variant pathogenicity and highlight several areas that require further resource development.
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Lee K, Chiu I, Santos-Cortez RLP, Basit S, Khan S, Azeem Z, Andrade PB, Kim SS, Ahmad W, Leal SM. Novel OTOA mutations cause autosomal recessive non-syndromic hearing impairment in Pakistani families. Clin Genet 2013; 84:294-6. [PMID: 23173898 PMCID: PMC6220893 DOI: 10.1111/cge.12047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lee K, Khan S, Islam A, Ansar M, Andrade PB, Kim S, Santos-Cortez RLP, Ahmad W, Leal SM. Novel TMPRSS3 variants in Pakistani families with autosomal recessive non-syndromic hearing impairment. Clin Genet 2011; 82:56-63. [PMID: 21534946 DOI: 10.1111/j.1399-0004.2011.01695.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mutations in the TMPRSS3 gene are known to cause autosomal recessive non-syndromic hearing impairment (ARNSHI). After undergoing a genome scan, 10 consanguineous Pakistani families with ARNSHI were found to have significant or suggestive evidence of linkage to the TMPRSS3 region. In order to elucidate if the TMPRSS3 gene is responsible for ARNSHI in these families, the gene was sequenced using DNA samples from these families. Six TMPRSS3 variants were found to cosegregate in 10 families. None of these variants were detected in 500 control chromosomes. Four novel variants, three of which are missense [c.310G>A (p.Glu104Lys), c.767C>T (p.Ala256Val) and c.1273T>C (p.Cys425Arg)] and one nonsense [c.310G>T (p.Glu104Stop)], were identified. The pathogenicity of novel missense variants was investigated through bioinformatics analyses. Additionally, the previously reported deletion c.208delC (p.His70ThrfsX19) was identified in one family and the known mutation c.1219T>C (p.Cys407Arg) was found in five families, which makes c.1219T>C (p.Cys407Arg) as the most common TMPRSS3 mutation within the Pakistani population. Identification of these novel variants lends support to the importance of elements within the low-density lipoprotein receptor A (LDLRA) and serine protease domains in structural stability, ligand binding and proteolytic activity for proper TMPRSS3 function within the inner ear.
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Mendoza-Fandino GA, Gee JM, Ben-Dor S, Gonzalez-Quevedo C, Lee K, Kobayashi Y, Hartiala J, Myers RM, Leal SM, Allayee H, Patel PI. A novel g.-1258G>A mutation in a conserved putative regulatory element of PAX9 is associated with autosomal dominant molar hypodontia. Clin Genet 2010; 80:265-72. [PMID: 21443745 DOI: 10.1111/j.1399-0004.2010.01529.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutations in the transcription factor PAX9 which plays a critical role in the switching of odontogenic potential from the epithelium to the mesenchyme during tooth development cause autosomal dominant non-syndromic hypodontia primarily affecting molars. Linkage analysis on a family segregating autosomal dominant molar hypodontia with markers flanking and within PAX9 yielded a maximum multipoint LOD score of 3.6. No sequence variants were detected in the coding or 5'- and 3'-untranslated regions (UTRs) of PAX9. However, we identified a novel g.-1258G>A sequence variant in all affected individuals of the family but not in the unaffected family members or in 3088 control chromosomes. This mutation is within a putative 5'-regulatory sequence upstream of PAX9 highly conserved in primates, somewhat conserved in ungulates and carnivores but not conserved in rodents. Bioinformatics analysis of the sequence determined that there was no abolition or creation of a putative binding site for known transcription factors. Based on our previous findings that haploinsufficiency for PAX9 leads to hypodontia, we postulate that the g.-1258G>A variant reduces the expression of PAX9 which underlies the hypodontia phenotype in this family.
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Kondkar AA, Bray MS, Leal SM, Nagalla S, Liu DJ, Jin Y, Dong JF, Ren Q, Whiteheart SW, Shaw C, Bray PF. VAMP8/endobrevin is overexpressed in hyperreactive human platelets: suggested role for platelet microRNA. J Thromb Haemost 2010; 8:369-78. [PMID: 19943878 PMCID: PMC3312605 DOI: 10.1111/j.1538-7836.2009.03700.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Variation in platelet reactivity contributes to disorders of hemostasis and thrombosis, but the molecular mechanisms are not well understood. OBJECTIVES To discover associations between interindividual platelet variability and the responsible platelet genes, and to begin to define the molecular mechanisms altering platelet gene expression. SUBJECTS/METHODS Two hundred and eighty-eight healthy subjects were phenotyped for platelet responsiveness. Platelet RNA from subjects demonstrating hyperreactivity (n=18) and hyporeactivity (n=11) was used to screen the human transcriptome. RESULTS Distinctly different mRNA profiles were observed between subjects with differing platelet reactivity. Increased levels of mRNA for VAMP8/endobrevin, a critical v-SNARE involved in platelet granule secretion, were associated with platelet hyperreactivity (Q=0.0275). Validation studies of microarray results showed 4.8-fold higher mean VAMP8 mRNA levels in hyperreactive than hyporeactive platelets (P=0.0023). VAMP8 protein levels varied 13-fold among platelets from these normal subjects, and were 2.5-fold higher in hyperreactive platelets (P=0.05). Among our cohort of 288 subjects, a VAMP8 single-nucleotide polymorphism (rs1010) was associated with platelet reactivity in an age-dependent manner (P<0.003). MicroRNA-96 was predicted to bind to the 3'-untranslated regionof VAMP8 mRNA and was detected in platelets. Overexpression of microRNA-96 in VAMP8-expressing cell lines caused a dose-dependent decrease in VAMP8 protein and mRNA, suggesting a role in VAMP8 mRNA degradation. CONCLUSIONS These findings support a role for VAMP8/endobrevin in the heterogeneity of platelet reactivity, and suggest a role for microRNA-96 in the regulation of VAMP8 expression.
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Teixeira MZ, Leal SM, Ceschin VMFA. Homeopathic practice in Intensive Care Units: objective semiology, symptom selection and a series of sepsis cases. HOMEOPATHY 2009; 97:206-13. [PMID: 19371570 DOI: 10.1016/j.homp.2008.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 06/15/2008] [Accepted: 08/06/2008] [Indexed: 11/15/2022]
Abstract
Homeopathy has been used for more than two hundred years to treat chronic disease using various approaches in a wide range of diseases. However, for acute disease and critical illness, application has been limited by inadequate training of homeopathic physicians and the small number of pertinent clinical studies. In view of the difficulty of practising homeopathy in Intensive Care Units (ICU), a protocol was developed to facilitate description of objective homeopathic symptoms with a ranking of symptoms appropriate for these situations (Protocol for Objective Homeopathic Semiology). Examples of favorable results with individualized homeopathic treatments for a series of cases of Systemic Inflammatory Response Syndrome (sepsis) are described.
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Leal SM, Qian L, Lacin H, Bodmer R, Skeath JB. Neuromancer1 and Neuromancer2 regulate cell fate specification in the developing embryonic CNS of Drosophila melanogaster. Dev Biol 2008; 325:138-50. [PMID: 19013145 DOI: 10.1016/j.ydbio.2008.10.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Revised: 10/01/2008] [Accepted: 10/02/2008] [Indexed: 12/14/2022]
Abstract
T-box genes encode a large family of transcription factors that regulate many developmental processes in vertebrates and invertebrates. In addition to their roles in regulating embryonic heart and epidermal development in Drosophila, we provide evidence that the T-box transcription factors neuromancer1 (nmr1) and neuromancer2 (nmr2) play key roles in embryonic CNS development. We verify that nmr1 and nmr2 function in a partially redundant manner to regulate neuronal cell fate by inhibiting even-skipped (eve) expression in specific cells in the CNS. Consistent with their redundant function, nmr1 and nmr2 exhibit overlapping yet distinct protein expression profiles within the CNS. Of note, nmr2 transcript and protein are expressed in identical patterns of segment polarity stripes, defined sets of neuroblasts, many ganglion mother cells and discrete populations of neurons. However, while we observe nmr1 transcripts in segment polarity stripes and specific neural precursors in early stages of CNS development, we first detect Nmr1 protein in later stages of CNS development where it is restricted to discrete subsets of Nmr2-positive neurons. Expression studies identify nearly all Nmr1/2 co-expressing neurons as interneurons, while a single Eve-positive U/CQ motor neuron weakly co-expresses Nmr2. Lineage studies map a subset of Nmr1/2-positive neurons to neuroblast lineages 2-2, 6-1, and 6-2 while genetic studies reveal that nmr2 collaborates with nkx6 to regulate eve expression in the CNS. Thus, nmr1 and nmr2 appear to act together as members of the combinatorial code of transcription factors that govern neuronal subtype identity in the CNS.
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Bhatti A, Lee K, McDonald ML, Hassan MJ, Gutala R, Ansar M, Ahmad W, Leal SM. Mapping of a new autosomal recessive non-syndromic hearing impairment locus (DFNB45) to chromosome 1q43-q44. Clin Genet 2008; 73:395-8. [PMID: 18325041 DOI: 10.1111/j.1399-0004.2008.00976.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Naeem M, Jelani M, Lee K, Ali G, Chishti MS, Wali A, Gul A, John P, Hassan MJ, Leal SM, Ahmad W. Ectodermal dysplasia of hair and nail type: mapping of a novel locus to chromosome 17p12-q21.2. Br J Dermatol 2007; 155:1184-90. [PMID: 17107387 PMCID: PMC6155468 DOI: 10.1111/j.1365-2133.2006.07509.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Ectodermal dysplasias (EDs) describe a large and complex group of disorders characterized by abnormal development of the skin and appendages (hair, nails, teeth and sweat glands). Of the approximately 200 different EDs, about 30 have been studied at the molecular level. In an effort to understand the molecular bases of ED of hair and nail type, we studied a Pakistani consanguineous family with multiple affected individuals. OBJECTIVES To localize the gene responsible for the autosomal recessive form of ED of hair and nail type. METHODS Genotyping of nine members of the family, including five affected and four normal individuals was performed using microsatellite markers mapping to candidate regions, harbouring genes involved in related phenotypes. Five epithelial keratin genes located in the candidate region were sequenced to identify the pathogenic mutation. RESULTS We mapped the disease locus to a 24.2-cM interval flanked by markers D17S839 and D17S1299 on chromosome 17p12-q21.2 (Z(max) = 4.4). DNA sequencing of five epithelial keratin candidate genes, present in the disease locus, did not reveal any pathogenic mutation in the affected individuals. CONCLUSIONS The gene for ED of hair and nail type has been mapped to chromosome 17p12-q21.2 in a Pakistani consanguineous family. Failure to detect mutations in epithelial keratin genes suggests that the mutation may lie either in regulatory regions of one of the epithelial keratin genes or in another unknown gene, located in the linkage interval, with a possible role in the development of ectodermal appendages.
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Wali A, Ali G, John P, Lee K, Chishti MS, Leal SM, Ahmad W. Mapping of a gene for alopecia with mental retardation syndrome (APMR3) on chromosome 18q11.2-q12.2. Ann Hum Genet 2007; 71:570-7. [PMID: 17451405 PMCID: PMC6148758 DOI: 10.1111/j.1469-1809.2007.00362.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Alopecia with mental retardation syndrome (APMR) is a rare autosomal recessive disorder characterized by total or partial absence of hair from the scalp and other parts of the body and associated with mental retardation. Previously, we have reported the mapping of two alopecia and mental retardation genes (APMR1 and APMR2) on human chromosome 3. In the present study, after excluding both of these loci through linkage analysis, a whole genome scan was performed by genotyping 396 polymorphic microsatellite markers located on 22 autosomes and the X and Y chromosomes. A disease locus was mapped to a 10.9 cM region, flanked by markers D18S866 and D18S811, on chromosome 18q11.2-q12.2. A maximum two-point LOD score of 3.03 at theta= 0.0 was obtained with marker D18S1102. Multipoint linkage analysis resulted in maximum LOD scores of 4.03 with several markers in the candidate region. According to the Rutgers combined linkage-physical map of the human genome (build 36) this region covers 12.17 Mb. DNA sequence analysis of nine candidate genes including DSC3, DSC1, DSG1, DSG4, DSG3, ZNF397, ZNF271, ZNF24 and ZNF396 did not reveal any sequence variants in the affected individuals of the family presented here.
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Wali A, John P, Gul A, Lee K, Chishti MS, Ali G, Hassan MJ, Leal SM, Ahmad W. A novel locus for alopecia with mental retardation syndrome (APMR2) maps to chromosome 3q26.2-q26.31. Clin Genet 2006; 70:233-9. [PMID: 16922726 PMCID: PMC6155482 DOI: 10.1111/j.1399-0004.2006.00661.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Congenital alopecia may occur either alone or in association with ectodermal and other abnormalities. On the bases of such associations, several different syndromes featuring congenital alopecia can be distinguished. Alopecia with mental retardation syndrome (APMR) is a rare autosomal recessive disorder, clinically characterized by total or partial hair loss and mental retardation. In the present study, a five-generation Pakistani family with multiple affected individuals with APMR was ascertained. Patients in this family exhibited typical features of APMR syndrome. The disease locus was mapped to chromosome 3q26.2-q26.31 by carrying out a genome scan followed by fine mapping. A maximum two-point logarithm of odds (LOD) score of 2.93 at theta=0.0 was obtained at markers D3S3053 and D3S2309. Multipoint linkage analysis resulted in a maximum LOD score of 4.57 with several markers, which supports the linkage. The disease locus was flanked by markers D3S1564 and D3S2427, which corresponds to 9.6-cM region according to the Rutgers combined linkage-physical map of the human genome (build 35) and contains 5.6 Mb. The linkage interval of the APMR locus identified here does not overlap with the one described previously; therefore, this locus has been designated as APMR2.
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Wang QJ, Li QZ, Rao SQ, Lee K, Huang XS, Yang WY, Zhai SQ, Guo WW, Guo YF, Yu N, Zhao YL, Yuan H, Guan J, Leal SM, Han DY, Shen Y. AUNX1, a novel locus responsible for X linked recessive auditory and peripheral neuropathy, maps to Xq23-27.3. J Med Genet 2006; 43:e33. [PMID: 16816020 PMCID: PMC2564562 DOI: 10.1136/jmg.2005.037929] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND We report here the genetic characterisation of a large five generation Chinese family with the phenotypic features of auditory neuropathy and progressive peripheral sensory neuropathy, and the genetic feature of X linked recessive inheritance. Disease onset was at adolescence (at an average age of 13 years for six affected subjects). The degree of hearing impairment varied from mild to severe, with decreased otoacoustic emissions; auditory brainstem responses were lacking from onset. METHODS Two-point and multipoint model based linkage analysis using the MILNK and LINKMAP programs of the FASTLINK software package produced maximum two-point and multipoint LOD scores of 2.41 and 2.41, respectively. RESULTS These findings define a novel X linked auditory neuropathy locus/region (AUNX1, Xq23-q27.3). This region is 42.09 cM long and contains a 28.07 Mb region with flanking markers DXS1220 and DXS8084, according to the Rutgers Combined Linkage-Physical Map, build 35. However, mutation screen of the candidate gene SLC6A14 within the region did not identify the causative genetic determinant for this large Chinese family.
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Naeem M, Wajid M, Lee K, Leal SM, Ahmad W. A mutation in the hair matrix and cuticle keratin KRTHB5 gene causes ectodermal dysplasia of hair and nail type. J Med Genet 2006; 43:274-9. [PMID: 16525032 PMCID: PMC2563238 DOI: 10.1136/jmg.2005.033381] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Ectodermal dysplasias are developmental disorders affecting tissues of ectodermal origin. To date, four different types of ectodermal dysplasia involving only hair and nails have been described. In an effort to understand the molecular bases of this form of ectodermal dysplasia, large Pakistani consanguineous kindred with multiple affected individuals has been ascertained from a remote region in Pakistan. OBJECTIVE To identify the gene underlying the phenotype. METHODS Microsatellite markers were genotyped in candidate regions and two point and multipoint parametric linkage analysis carried out. RESULTS The disease locus was mapped to a 16.6 centimorgan region on chromosome 12q12-q14.1 (Zmax = 8.2), which harbours six type II hair keratin genes. DNA sequence analysis revealed a homozygous missense mutation in the hair matrix and cuticle keratin KRTHB5, leading to histidine substitution of a conserved arginine residue (R78H) located in the head domain. CONCLUSIONS This report provides the first direct evidence relating to the molecular pathogenesis of pure hair-nail ectodermal dysplasias.
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Ferguson PJ, Chen S, Tayeh MK, Ochoa L, Leal SM, Pelet A, Munnich A, Lyonnet S, Majeed HA, El-Shanti H. Homozygous mutations in LPIN2 are responsible for the syndrome of chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia (Majeed syndrome). J Med Genet 2006; 42:551-7. [PMID: 15994876 PMCID: PMC1736104 DOI: 10.1136/jmg.2005.030759] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Majeed syndrome is an autosomal recessive, autoinflammatory disorder characterised by chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia. The objectives of this study were to map, identify, and characterise the Majeed syndrome causal gene and to speculate on its function and role in skin and bone inflammation. METHODS Six individuals with Majeed syndrome from two unrelated families were identified for this study. Homozygosity mapping and parametric linkage analysis were employed for the localisation of the gene responsible for Majeed syndrome. Direct sequencing was utilised for the identification of mutations within the genes contained in the region of linkage. Expression studies and in silico characterisation of the identified causal gene and its protein were carried out. RESULTS The phenotype of Majeed syndrome includes inflammation of the bone and skin, recurrent fevers, and dyserythropoietic anaemia. The clinical picture of the six affected individuals is briefly reviewed. The gene was mapped to a 5.5 cM interval (1.8 Mb) on chromosome 18p. Examination of genes in this interval led to the identification of homozygous mutations in LPIN2 in affected individuals from the two families. LPIN2 was found to be expressed in almost all tissues. The function of LPIN2 and its role in inflammation remains unknown. CONCLUSIONS We conclude that homozygous mutations in LPIN2 result in Majeed syndrome. Understanding the aberrant immune response in this condition will shed light on the aetiology of other inflammatory disorders of multifactorial aetiology including isolated chronic recurrent multifocal osteomyelitis, Sweet syndrome, and psoriasis.
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Pedra SRFF, Hornberger LK, Leal SM, Taylor GP, Smallhorn JF. Cardiac function assessment in patients with family history of nonhypertrophic cardiomyopathy: a prenatal and postnatal study. Pediatr Cardiol 2005; 26:543-52. [PMID: 16132314 DOI: 10.1007/s00246-004-0688-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Nonobstructive cardiomyopathies (CMs) may be familial in 20â<euro>"55% of cases. Little is known about the role of fetal echocardiography in such cases. We evaluated the cardiac function serially pre- and postnatally in cases with a family history of nonobstructive CM. The fetal and postnatal studies were performed in the echocardiogarphy laboratory at a tertiary institution. Twenty-six cases from 16 families with a family history of CM were studied. Three fetal echocardiograms were performed at or near 18, 25, and 32 weeks of gestation for complete cardiac functional assessment. Postnatally clinical evaluation, electrocardiogram, and an echocardiogram were performed within the first 3 months, with serial reevaluation for those identified with CM. The mean follow-up was 46 +/- 9 months. Abnormal cardiac function was observed in 8 cases (30%). Six had a previously affected sibling, 1 had other family members affected, and 1 had both antecedents. Four had dilated CM diagnosed prenatally of which 1 recovered, 2 died in utero, and 1 died soon after birth. The remaining 4 had normal fetal echoes and were diagnosed with CM in the first 3 months of life. Three had dilated CM with recovery, and 1 had restrictive CM requiring cardiac transplantation. This study demonstrates a high familial recurrence rate of CM. Fetal echo is useful for early diagnosis, although a normal study does not preclude ventricular dysfunction at a later stage, justifying serial prenatal and postnatal evaluation. Early identification may expedite listing for transplantation.
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Irshad S, Santos RLP, Muhammad D, Lee K, McArthur N, Haque S, Ahmad W, Leal SM. Localization of a novel autosomal recessive non-syndromic hearing impairment locus DFNB55 to chromosome 4q12-q13.2. Clin Genet 2005; 68:262-7. [PMID: 16098016 PMCID: PMC2910366 DOI: 10.1111/j.1399-0004.2005.00492.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hereditary hearing impairment (HI) is the most genetically heterogeneous trait known in humans. So far, 54 autosomal recessive non-syndromic hearing impairment (ARNSHI) loci have been mapped, and 21 ARNSHI genes have been identified. Here is reported the mapping of a novel ARNSHI locus, DFNB55, to chromosome 4q12-q13.2 in a consanguineous Pakistani family. A maximum multipoint LOD score of 3.5 was obtained at marker D4S2638. The region of homozygosity and the 3-unit support interval are flanked by markers D4S2978 and D4S2367. The region spans 8.2 cm on the Rutgers combined linkage-physical map and contains 11.5 Mb. DFNB55 represents the third ARNSHI locus mapped to chromosome 4.
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Santos RLP, Wajid M, Pham TL, Hussan J, Ali G, Ahmad W, Leal SM. Low prevalence of Connexin 26 (GJB2) variants in Pakistani families with autosomal recessive non-syndromic hearing impairment. Clin Genet 2005; 67:61-8. [PMID: 15617550 PMCID: PMC2909104 DOI: 10.1111/j.1399-0004.2005.00379.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The Pakistani population has become an important resource for research on autosomal recessive non-syndromic hearing impairment (ARNSHI) due to the availability of large extended and highly consanguineous pedigrees. Here is presented the first report on the prevalence of gap junction beta-2 (GJB2) variants in Pakistan. One hundred and ninety-six unrelated Pakistani families with ARNSHI were recruited for a study on the genetics of NSHI. DNA sequencing of the GJB2 coding region was done on two affected individuals per family. Evolutionary conservation and predicted effect on the protein product were studied in order to hypothesize whether or not a variant was potentially deleterious. Homozygous putatively functional GJB2 variants were identified in 6.1% of families. None of the putatively functional GJB2 variants were observed in the compound heterozygous state. The six putatively causative variants noted were 231G > A(W77X), 71G > A(W24X), 167delT, 95G > A(R32H), 358-360delGAG(delE120), and 269T > C(L90P), with 231G > A(W77X) and 71G > A(W24X) being the most common. In addition, five benign polymorphisms, 380G > A(R127H), 457G > A(V153I), 493C > T(R165W), 79G > A(V27I), and 341 A > G(E114G), were identified within this population. In a few individuals, benign polymorphisms were observed to occur on the same haplotype, namely [457G > A(V153I); 493C > T(R165W)] and [79G > A(V27I); 341 A > G(E114G)]. The spectrum of GJB2 sequence variants in Pakistan may reflect shared origins of hearing impairment alleles within the Indian subcontinent. The high degree of consanguinity within Pakistan may have maintained the GJB2 prevalence at a much lower rate than within India and other populations.
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Aslam M, Chahrour MH, Razzaq A, Haque S, Yan K, Leal SM, Ahmad W. A novel locus for autosomal recessive form of hypotrichosis maps to chromosome 3q26.33-q27.3. J Med Genet 2005; 41:849-52. [PMID: 15520410 PMCID: PMC1735610 DOI: 10.1136/jmg.2004.019729] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Rafiq MA, Ansar M, Pham T, Amin-ud-Din M, Anwar M, Haque S, Chahrour MH, Yan K, Leal SM, Ahmad W. Localization of a novel locus for hereditary nail dysplasia to chromosome 17q25.1-17q25.3. Clin Genet 2005; 66:73-8. [PMID: 15200512 PMCID: PMC6141021 DOI: 10.1111/j.0009-9163.2004.00273.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report on a six-generation Pakistani consanguineous family with autosomal recessive transmission of a form of hereditary nail dysplasia. Affected individuals presented with onycholysis of fingernails and anonychia of toenails. Associated abnormalities of ectodermal appendages were not observed in any of the affected individuals. Linkage has been established to chromosome 17q. A maximum multipoint analysis logarithm of the odds ratio score of 4.85 was obtained at marker D17S1301. Due to the consanguineous nature of this kindred, the gene for nail dysplasia is probably contained within a 5.0-cM (3 MB on the sequence-based physical map) region of homozygosity flanked by markers D17S1807 and D17S937.
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Mims MP, Maran J, Leal SM, Hayes TG, Ittmann M, Wheeler T, Guan Y, Prchal JT. Role of African American genetic polymorphisms in prostate cancer. J Clin Oncol 2004. [DOI: 10.1200/jco.2004.22.90140.4710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Bart G, Heilig M, LaForge KS, Pollak L, Leal SM, Ott J, Kreek MJ. Substantial attributable risk related to a functional mu-opioid receptor gene polymorphism in association with heroin addiction in central Sweden. Mol Psychiatry 2004; 9:547-9. [PMID: 15037869 PMCID: PMC6141020 DOI: 10.1038/sj.mp.4001504] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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