1
|
Strachan T, Read AP. Comparative genomics and genome evolution. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
2
|
Strachan T, Read AP. Uncovering the architecture and workings of the human genome. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
3
|
Strachan T, Read AP. Mapping and identifying genes for monogenic disorders. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
4
|
Strachan T, Read AP. Human evolution. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
5
|
Strachan T, Read AP. Genetic testing in healthcare and the law. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
6
|
Strachan T, Read AP. Core DNA technologies: amplifying DNA, nucleic acid hybridization, and DNA sequencing. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
7
|
Strachan T, Read AP. Analyzing the structure and expression of genes and genomes. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
8
|
Strachan T, Read AP. Aspects of early mammalian development, cell differentiation, and stem cells. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
9
|
Strachan T, Read AP. Patterns of inheritance. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
10
|
Strachan T, Read AP. Complex disease: identifying susceptibility factors and understanding pathogenesis. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
11
|
Strachan T, Read AP. Principles of genetic manipulation of mammalian cells. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
12
|
Strachan T, Read AP. Genetic approaches to treating disease. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
13
|
Strachan T, Read AP. Model organisms and modeling disease. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
14
|
Strachan T, Read AP. Chromosomal abnormalities and structural variants. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
15
|
Strachan T, Read AP. Human population genetics. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
16
|
Strachan T, Read AP. Molecular pathology: connecting phenotypes to genotypes. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
17
|
Strachan T, Read AP. Fundamentals of cells and chromosomes. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
18
|
Strachan T, Read AP. Gene regulation and the epigenome. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
19
|
Strachan T, Read AP. Cancer genetics and genomics. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
20
|
Strachan T, Read AP. Basic principles of nucleic acid structure and gene expression. Hum Mol Genet 2018. [DOI: 10.1201/9780429448362-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
21
|
|
22
|
Read AP. The Human Genome—Structure and Organization. Genomic Med 2014. [DOI: 10.1093/med/9780199896028.003.0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
23
|
Read AP, Donnai D. What can be offered to couples at (possibly) increased genetic risk? J Community Genet 2012; 3:167-74. [PMID: 22760671 DOI: 10.1007/s12687-012-0105-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 06/15/2012] [Indexed: 11/26/2022] Open
Abstract
We review the reasons why a couple might seek specialist genetic counselling about a possible reproductive risk and the options available to them. Most commonly, the couple will be concerned about the risk of recurrence of a medical condition that has already occurred in the family. Sometimes, the increased risk may come from their ethnicity or because of a consanguineous marriage, rather than because any problem has occurred previously. The geneticist must identify the exact nature of any problem and determine the risks in the light of the mode of inheritance, any investigations undertaken and any other relevant information. The geneticist will then review the options open to the couple, and help them arrive at their own decision in a non-directive way. Some couples may opt to do nothing and let nature take its course but others may request prenatal or pre-implantation diagnosis, or they may avoid the conception of an at-risk child by using donor gametes, adoption or even decide not to have children.
Collapse
Affiliation(s)
- Andrew P Read
- Department of Genetic Medicine, St Mary's Hospital, Manchester, M13 0JH, UK,
| | | |
Collapse
|
24
|
|
25
|
Abstract
Otosclerosis is one of the commonest causes of hearing loss in adults. The hereditary nature of the disease has been acknowledged for over a century but the precise genetic basis of the disorder has as yet not been characterised. It is currently recognised that familial otosclerosis exhibits autosomal dominant inheritance with variable penetrance and expression. More recently, family linkage studies have identified three chromosomal regions that can be ascribed to this disorder: otosclerosis 1 on chromosome 15, otosclerosis 2 on chromosome 7 and a third locus on chromosome 6. The genes responsible for the disease within these regions remain to be defined. The work presented in this paper firstly examined the familial nature of the disease in a cohort of individuals that had undergone surgery for otosclerosis. Following detailed ascertainment, pedigrees were constructed for subsequent genetic analysis. The laboratory analysis included linkage analysis of the candidate region on the long arm of chromosome 15, linkage analysis of the aggrecan protein gene within the 15q region and linkage analysis to chromosome 7q. The pedigree studies confirmed the hereditary nature of otosclerosis and the recognised mode of inheritance. Linkage to the chromosome 15 locus, the candidate aggrecan gene and the chromosome 7 locus was excluded, confirming that otosclerosis exhibits locus heterogeneity.
Collapse
Affiliation(s)
- S R Saeed
- University Department of Otolaryngology-Head and Neck Surgery, Manchester Royal Infirmary and Department of Clinical Genetics, St. Mary's Hospital, Manchester, UK
| | | | | | | | | | | |
Collapse
|
26
|
Banerjee I, Trueman JA, Hall CM, Price DA, Patel L, Whatmore AJ, Hirschhorn JN, Read AP, Palmert MR, Clayton PE. Phenotypic variation in constitutional delay of growth and puberty: relationship to specific leptin and leptin receptor gene polymorphisms. Eur J Endocrinol 2006; 155:121-6. [PMID: 16793957 DOI: 10.1530/eje.1.02184] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Constitutional delay of growth and puberty (CDGP) is a variant of normal pubertal timing and progress, often with dominant inheritance. It is likely that one or more genes will be associated with CDGP. Possible candidates are the leptin (L) and the leptin receptor (LR) genes, as the leptin axis links nutritional status to pubertal development. This study has assessed whether a) L or LR gene polymorphisms were associated with CDGP and b) the CDGP phenotype was influenced by these polymorphisms. DESIGN Case-control and transmission disequilibrium tests were used to test genetic association of L and LR polymorphisms with CDGP. METHODS We genotyped L (3'CTTT repeat) and LR polymorphisms (Gln > Arg substitution, exon 6) in 81 CDGP children and 94 controls in the UK and 88 CDGP children from the US and assessed the effect of genotype on their anthropometric characteristics. RESULTS There was no association of these L or LR gene polymorphisms with CDGP. There was no difference in height or bone age delay within L or LR genotypes. However, UK CDGP children homozygous for the L short allele were heavier than heterozygotes and long allele homozygotes, with a similar trend in the US cohort. UK CDGP children with severe pubertal delay, who were thin, had significantly greater bone age delay and an increased frequency of parental pubertal delay than other groups and were less likely to be L short allele homozygotes. CONCLUSIONS There was no association of specific L or LR polymorphisms with CDGP, but L short allele carriage influenced the phenotype within CDGP.
Collapse
Affiliation(s)
- Indraneel Banerjee
- Department of Paediatric Endocrinology, Royal Manchester Children's Hospital, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Read AP. John C. Avise: The hope, hype and reality of genetic engineering (2004). Hum Genet 2006. [DOI: 10.1007/s00439-005-0128-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
28
|
Tassabehji M, Hammond P, Karmiloff-Smith A, Thompson P, Thorgeirsson SS, Durkin ME, Popescu NC, Hutton T, Metcalfe K, Rucka A, Stewart H, Read AP, Maconochie M, Donnai D. GTF2IRD1 in craniofacial development of humans and mice. Science 2005; 310:1184-7. [PMID: 16293761 DOI: 10.1126/science.1116142] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Craniofacial abnormalities account for about one-third of all human congenital defects, but our understanding of the genetic mechanisms governing craniofacial development is incomplete. We show that GTF2IRD1 is a genetic determinant of mammalian craniofacial and cognitive development, and we implicate another member of the TFII-I transcription factor family, GTF2I, in both aspects. Gtf2ird1-null mice exhibit phenotypic abnormalities reminiscent of the human microdeletion disorder Williams-Beuren syndrome (WBS); craniofacial imaging reveals abnormalities in both skull and jaws that may arise through misregulation of goosecoid, a downstream target of Gtf2ird1. In humans, a rare WBS individual with an atypical deletion, including GTF2IRD1, shows facial dysmorphism and cognitive deficits that differ from those of classic WBS cases. We propose a mechanism of cumulative dosage effects of duplicated and diverged genes applicable to other human chromosomal disorders.
Collapse
Affiliation(s)
- May Tassabehji
- Academic Unit of Medical Genetics, University of Manchester, St. Mary's Hospital, Manchester M13 9PL, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Hewitt C, Wu CL, Hattab FN, Amin W, Ghaffar KA, Toomes C, Sloan P, Read AP, James JA, Thakker NS. Coinheritance of two rare genodermatoses (Papillon-Lefèvre syndrome and oculocutaneous albinism type 1) in two families: a genetic study. Br J Dermatol 2005; 151:1261-5. [PMID: 15606524 DOI: 10.1111/j.1365-2133.2004.06237.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The co-occurrence of two rare recessive genetic conditions in apparently unrelated individuals or families is extremely rare. Two geographically distant and apparently unrelated families were identified in which individuals were simultaneously affected by two rare recessive mendelian syndromes, Papillon-Lefevre syndrome and type 1 oculocutaneous albinism. The families were tested for mutations in the causative genes, cathepsin C (CTSC) and tyrosinase (TYR), respectively, by direct sequencing. To assess the relationship of the two families, both families were tested for polymorphisms at eight microsatellite markers spanning both CTSC and TYR loci. Independent mutations (c.318-1G-->A and c.817G-->C/p.W272C) were identified in CTSC and TYR, respectively, that were shared by the affected individuals in both families. The two affected genes lie close together on chromosome bands 11q14.2-14.3, and studies with linked genetic markers suggested that the families shared a small chromosomal segment carrying both mutations that had been transmitted intact from a remote common ancestor. The co-occurrence of the two rare diseases in multiple families depends on their shared chromosomal location, but not on any shared pathogenic mechanism.
Collapse
Affiliation(s)
- C Hewitt
- Unit of Medical Genetics, University of Manchester and the Regional Molecular Genetics Service, St Mary's Hospital, Manchester M13 0JH, U.K
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Sedlmeyer IL, Pearce CL, Trueman JA, Butler JL, Bersaglieri T, Read AP, Clayton PE, Kolonel LN, Henderson BE, Hirschhorn JN, Palmert MR. Determination of sequence variation and haplotype structure for the gonadotropin-releasing hormone (GnRH) and GnRH receptor genes: investigation of role in pubertal timing. J Clin Endocrinol Metab 2005; 90:1091-9. [PMID: 15546906 DOI: 10.1210/jc.2004-0649] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Because GnRH and its receptor (GnRHR) are pivotal regulators of the reproductive endocrine axis and mutations in GNRHR lead to hypogonadotropic hypogonadism, we investigated whether genetic variation in GNRHR or GNRH1 affects pubertal timing in the general population. To screen for missense mutations in these genes that might affect pubertal timing, we resequenced the coding regions of these genes in 48 probands with late but otherwise normal pubertal development. No missense variants were found in either gene, except for a previously identified single nucleotide polymorphism (SNP) in GNRH1 that was not associated with late pubertal development. To search for common variants that might affect pubertal timing, we took a haplotype-based association approach. To identify common haplotypes in these genes, we genotyped 41 SNPs in DNA from commercially available European-derived multigenerational pedigrees and participants in a multiethnic cohort (MEC). Two blocks of strong linkage disequilibrium were identified that spanned GNRHR and one was identified spanning GNRH1; within each block, more than 80% of chromosomes carried one of a few common haplotypes. A set of haplotype-tagging SNPs that mark these common haplotypes in all five ethnic groups within the MEC were defined and used to perform association studies among 125 trios (probands with late pubertal development and their parents) and 506 women from the MEC who had early (menarche < 11 yr of age, n = 216) or late (menarche > or = 15 yr of age, n = 290) pubertal development. Three SNPs in GNRHR showed modest association with late pubertal development in the trios; among the 506 women, a different SNP was associated with late menarche, and one rare haplotype was associated with early age of menarche. All of the observed associations were relatively modest and only nominally statistically significant; replication is needed to determine their validity. We conclude that genetic variation in GNRH1 and GNRHR is not likely to be a substantial modulator of pubertal timing in the general population.
Collapse
Affiliation(s)
- Ines L Sedlmeyer
- Division of Endocrinology and Genetics, Department of Medicine, Children's Hospital, Hravard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Manson FDC, Trump D, Read AP, Black GCM. Inherited eye disease: cause and late effect. Trends Mol Med 2005; 11:449-55. [PMID: 16153893 DOI: 10.1016/j.molmed.2005.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 07/12/2005] [Accepted: 08/16/2005] [Indexed: 01/14/2023]
Abstract
Molecular genetics has provided relatively few insights into late-onset eye disorders, but epidemiological data indicate that genetic factors are important in some late-onset eye disorders that cause major health burdens. Much clinical genetic research is based on the belief that developmental and late-onset disorders are not necessarily the result of defects in different genes, but are often caused by different mutations in the same collection of genes. Thus, mutations that either abolish or radically change gene function might cause early-onset disorders, whereas more-subtle changes in gene expression might underlie late-onset diseases. We present arguments and examples that indicate that this principle might be a fruitful guide to investigating the causes of late-onset eye disorders.
Collapse
Affiliation(s)
- Forbes D C Manson
- Academic Unit of Eye and Vision Science, Manchester Royal Eye Hospital, School of Medicine, University of Manchester, Oxford Road, Manchester M13 9WH, UK
| | | | | | | |
Collapse
|
32
|
Hewitt C, Wilson P, McGlinn E, MacFarlane G, Papageorgiou A, Woodwards RTM, Sloan P, Gollin SM, Paterson I, Parkinson KK, Read AP, Thakker N. DLC1 is unlikely to be a primary target for deletions on chromosome arm 8p22 in head and neck squamous cell carcinoma. Cancer Lett 2004; 209:207-13. [PMID: 15159023 DOI: 10.1016/j.canlet.2003.12.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 11/30/2003] [Accepted: 12/12/2003] [Indexed: 01/01/2023]
Abstract
Allelic imbalance on chromosome arm 8p is common in head and neck squamous cell carcinoma (HNSCC). DLC1, a tumour suppressor gene inactivated in liver carcinogenesis and encoding a Rho GTPase activating protein (RhoGAP) maps to one of the deleted regions (8p21.3-22). In order to determine whether inactivation of DLC1 is involved in HNSCC, we have screened tumour cell lines for DLC1 mutations and expression. Pathological mutations were not identified in any of the 17 cell lines tested. Seven polymorphisms were identified; 13 of the 17 of cell lines were homozygous for all seven polymorphisms compared to only 2 of 17 controls suggesting a loss of heterozygosity in a majority of the cell lines. DLC1 expression was observed in all 11 HNSCC cell lines tested, thus excluding the possibility of transcriptional silencing of DLC1 by promoter hypermethylation. Overall, our data suggest that hemizygous deletions of the DLC1 locus are frequent in HNSCCs but this gene is unlikely to be primary target for inactivation on this chromosomal arm.
Collapse
Affiliation(s)
- Chelsee Hewitt
- Unit of Medical Genetics, University of Manchester, St Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Hewitt C, McCormick D, Linden G, Turk D, Stern I, Wallace I, Southern L, Zhang L, Howard R, Bullon P, Wong M, Widmer R, Gaffar KA, Awawdeh L, Briggs J, Yaghmai R, Jabs EW, Hoeger P, Bleck O, Rüdiger SG, Petersilka G, Battino M, Brett P, Hattab F, Al-Hamed M, Sloan P, Toomes C, Dixon M, James J, Read AP, Thakker N. The role of cathepsin C in Papillon-Lefèvre syndrome, prepubertal periodontitis, and aggressive periodontitis. Hum Mutat 2004; 23:222-8. [PMID: 14974080 DOI: 10.1002/humu.10314] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have previously reported that loss-of-function mutations in the cathepsin C gene (CTSC) result in Papillon-Lefèvre syndrome, an autosomal recessive condition characterized by palmoplantar keratosis and early-onset, severe periodontitis. Others have also reported CTSC mutations in patients with severe prepubertal periodontitis, but without any skin manifestations. The possible role of CTSC variants in more common types of non-mendelian, early-onset, severe periodontitis ("aggressive periodontitis") has not been investigated. In this study, we have investigated the role of CTSC in all three conditions. We demonstrate that PLS is genetically homogeneous and the mutation spectrum that includes three novel mutations (c.386T>A/p.V129E, c.935A>G/p.Q312R, and c.1235A>G/p.Y412C) in 21 PLS families (including eight from our previous study) provides an insight into structure-function relationships of CTSC. Our data also suggest that a complete loss-of-function appears to be necessary for the manifestation of the phenotype, making it unlikely that weak CTSC mutations are a cause of aggressive periodontitis. This was confirmed by analyses of the CTSC activity in 30 subjects with aggressive periodontitis and age-sex matched controls, which demonstrated that there was no significant difference between these two groups (1,728.7 +/- SD 576.8 micro moles/mg/min vs. 1,678.7 +/- SD 527.2 micro moles/mg/min, respectively, p = 0.73). CTSC mutations were detected in only one of two families with prepubertal periodontitis; these did not form a separate functional class with respect to those observed in classical PLS. The affected individuals in the other prepubertal periodontitis family not only lacked CTSC mutations, but in addition did not share the haplotypes at the CTSC locus. These data suggest that prepubertal periodontitis is a genetically heterogeneous disease that, in some families, just represents a partially penetrant PLS.
Collapse
Affiliation(s)
- Chelsee Hewitt
- Department of Medical Genetics University of Manchester, Manchester, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Read AP. David Bainbridge (Editor), The X in sex: how the X chromosome controls our lives. Hum Genet 2004. [DOI: 10.1007/s00439-003-1052-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
35
|
Abstract
Studies of human birth defects and developmental disorders have made major contributions to our understanding of development. Rare human syndromes have allowed identification of important developmental genes, and revealed mechanisms such as uniparental disomy and unstable trinucleotide repeats that were not suspected from animal studies. Some aspects of development, in particular cognitive development, can only be studied in human beings. Basic developmental mechanisms are very highly conserved across a very wide range of animals, making for a rich interplay between animal and human studies. Often, clinical studies identify a gene, or suggest a hypothesis, that can then be investigated in animals.
Collapse
Affiliation(s)
- Dian Donnai
- University of Manchester, Academic Unit of Medical Genetics and Regional Genetic Service, St Mary's Hospital, M13 0JH, Manchester, UK.
| | | |
Collapse
|
36
|
Abstract
Pax genes are a highly conserved family of developmental control genes that encode transcription factors. In vertebrates, Pax genes play a role in pattern formation during embryogenesis. Mutations in Pax genes have been associated with both spontaneous mouse mutants and congenital human diseases. The mouse Pax1 mutant phenotype undulated is characterised by vertebral segmentation defects reminiscent of the human disorder Klippel-Feil syndrome (KFS). To determine whether PAX1 haploinsufficiency plays a role in KFS, we have defined the gene structure of the human PAX1 gene and screened 63 KFS patients for mutations in this gene. Differences in the PAX1 sequence were detected in eight patients. Two patients had a silent change within the paired box that was also seen in 2/303 control chromosomes. The other variants were missense, silent or intronic changes not represented in the control panel tested. The significance of these results and the possible role of PAX1 in the pathogenesis of KFS are discussed.
Collapse
Affiliation(s)
- J M McGaughran
- Queensland Clinical Genetics Service, Royal Children's Hospital and Health District, Herston, Brisbane 4029, Queensland, Australia
| | | | | | | | | |
Collapse
|
37
|
Karmiloff-Smith A, Grant J, Ewing S, Carette MJ, Metcalfe K, Donnai D, Read AP, Tassabehji M. Using case study comparisons to explore genotype-phenotype correlations in Williams-Beuren syndrome. J Med Genet 2003; 40:136-40. [PMID: 12566524 PMCID: PMC1735363 DOI: 10.1136/jmg.40.2.136] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
38
|
Sánchez-Martín M, Rodríguez-García A, Pérez-Losada J, Sagrera A, Read AP, Sánchez-García I. SLUG (SNAI2) deletions in patients with Waardenburg disease. Hum Mol Genet 2002; 11:3231-6. [PMID: 12444107 DOI: 10.1093/hmg/11.25.3231] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Waardenburg syndrome (WS; deafness with pigmentary abnormalities) is a congenital disorder caused by defective function of the embryonic neural crest. Depending on additional symptoms, WS is classified into four types: WS1, WS2, WS3 and WS4. WS1 and WS3 are caused by mutations in PAX3, whereas WS2 is heterogenous, being caused by mutations in the microphthalmia (MITF) gene in some but not all affected families. The identification of Slugh, a zinc-finger transcription factor expressed in migratory neural crest cells, as the gene responsible for pigmentary disturbances in mice prompted us to analyse the role of its human homologue SLUG in neural crest defects. Here we show that two unrelated patients with WS2 have homozygous deletions in SLUG which result in absence of the SLUG product. We further show that Mitf is present in Slug-deficient cells and transactivates the SLUG promoter, and that Slugh and Kit genetically interact in vivo. Our findings further define the locus heterogeneity of WS2 and point to an essential role of SLUG in the development of neural crest-derived human cell lineages: its absence causes the auditory-pigmentary symptoms in at least some individuals with WS2.
Collapse
Affiliation(s)
- Manuel Sánchez-Martín
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Centro de Investigación del Cáncer, CSIC/Universidad de Salamanca, Campus Unamuno, 37007 Salamanca, Spain
| | | | | | | | | | | |
Collapse
|
39
|
Abstract
Familial melanoma predisposition is associated with germline mutations at the CDKN2A/ARF locus in up to 40% of families. The exact role of the two proteins encoded by this complex locus in this predisposition is unclear. Most mutations affect either CDKN2A only or products of both genes. Recently a deletion affecting ARF-specific exon 1beta was reported in a family with melanoma and neural tumours. However, the possibility of this deletion also altering the CDKN2A transcript could not be excluded. More convincingly, a 16 base pair insertion in exon 1beta has been reported in an individual with multiple melanomas suggesting a direct role for ARF in melanoma predisposition. We report here a splice mutation in exon 1beta in a family with melanoma that results in ARF haploinsufficiency. The mutation was observed in a mother and daughter with melanoma. A sibling of the mother with breast cancer also had this mutation. Analysis of the melanoma from one individual revealed a 62 bp deletion in exon 3 of the wildtype allele and loss of the mutant allele; these somatic changes would affect both CDKN2A and ARF. These somatic events suggest that concomitant inactivation of both ARF and CDKN2A may be necessary for melanoma development and that mutations in ARF and CDKN2A possibly confer different levels of susceptibility to melanoma, with the former associated with lesser predisposition. In this situation, the events follow a 'three-hit' model as observed in tumours from FAP patients with an attenuated phenotype. Overall, the data suggest a direct role for ARF haploinsufficiency in melanoma predisposition and co-operation between ARF and CDKN2A in tumour formation, consistent with recent observations in Cdkn2a-specific knockout mice.
Collapse
Affiliation(s)
- Chelsee Hewitt
- University of Manchester Department of Medical Genetics and Regional Genetic Service, Central Manchester Healthcare Trust, St. Mary's Hospital, Manchester, M13 OJH, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Müllner-Eidenböck A, Moser E, Frisch H, Read AP. Waardenburg syndrome type 2 in a Turkish family: implications for the importance of the pattern of fundus pigmentation. Br J Ophthalmol 2001; 85:1384-6. [PMID: 11702731 PMCID: PMC1723753 DOI: 10.1136/bjo.85.11.1384] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
41
|
Abstract
UNLABELLED Hereditary deafness is highly heterogeneous genetically, with over 100 loci so far identified. Routine diagnostic mutation screening can be done only when a candidate gene has been identified, and preferably a candidate mutation. For syndromic forms of hearing loss it is often possible to predict the gene involved. Non-syndromic loss is much more intractable to diagnostic mutation screening because of the extensive locus heterogeneity. However, mutations in the connexin 26 (GJB2) gene and the mitochondrial m. 1555A > G mutation are sufficiently frequent in some populations to justify mutation testing. Identifying the genes mutated in syndromic hearing loss can help delineate developmental pathways. CONCLUSION The example of Waardenburg syndrome is used to illustrate how unravelling developmental pathways can be more complicated than defining metabolic pathways through biochemical defects. Developmental genes tend to be organised into networks rather than linear pathways, and transcription factors act in a combinatorial manner. This makes developmental pathways harder to unravel genetically than metabolic pathways.
Collapse
Affiliation(s)
- A P Read
- Department of Medical Genetics, St Mary's Hospital, Manchester, UK.
| |
Collapse
|
42
|
Metcalfe K, Rucka AK, Smoot L, Hofstadler G, Tuzler G, McKeown P, Siu V, Rauch A, Dean J, Dennis N, Ellis I, Reardon W, Cytrynbaum C, Osborne L, Yates JR, Read AP, Donnai D, Tassabehji M. Elastin: mutational spectrum in supravalvular aortic stenosis. Eur J Hum Genet 2000; 8:955-63. [PMID: 11175284 DOI: 10.1038/sj.ejhg.5200564] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Supravalvular aortic stenosis (SVAS) is a congenital narrowing of the ascending aorta which can occur sporadically, as an autosomal dominant condition, or as one component of Williams syndrome. SVAS is caused by translocations, gross deletions and point mutations that disrupt the elastin gene (ELN) on 7q11.23. Functional hemizygosity for elastin is known to be the cause of SVAS in patients with gross chromosomal abnormalities involving ELN. However, the pathogenic mechanisms of point mutations are less clear. One hundred patients with diagnosed SVAS and normal karyotypes were screened for mutations in the elastin gene to further elucidate the molecular pathology of the disorder. Mutations associated with the vascular disease were detected in 35 patients, and included nonsense, frameshift, translation initiation and splice site mutations. The four missense mutations identified are the first of this type to be associated with SVAS. Here we describe the spectrum of mutations occurring in familial and sporadic SVAS and attempt to define the mutational mechanisms involved in SVAS. SVAS shows variable penetrance within families but the progressive nature of the disorder in some cases, makes identification of the molecular lesions important for future preventative treatments.
Collapse
Affiliation(s)
- K Metcalfe
- University Department of Medical Genetics and Regional Genetics Service, St Mary's Hospital, Manchester, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Affiliation(s)
- A P Read
- Department of Medical Genetics, St Mary's Hospital, Manchester, UK.
| |
Collapse
|
44
|
Toomes C, James J, Wood AJ, Wu CL, McCormick D, Lench N, Hewitt C, Moynihan L, Roberts E, Woods CG, Markham A, Wong M, Widmer R, Ghaffar KA, Pemberton M, Hussein IR, Temtamy SA, Davies R, Read AP, Sloan P, Dixon MJ, Thakker NS. Loss-of-function mutations in the cathepsin C gene result in periodontal disease and palmoplantar keratosis. Nat Genet 1999; 23:421-4. [PMID: 10581027 DOI: 10.1038/70525] [Citation(s) in RCA: 336] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Papillon-Lefèvre syndrome, or keratosis palmoplantaris with periodontopathia (PLS, MIM 245000), is an autosomal recessive disorder that is mainly ascertained by dentists because of the severe periodontitis that afflicts patients. Both the deciduous and permanent dentitions are affected, resulting in premature tooth loss. Palmoplantar keratosis, varying from mild psoriasiform scaly skin to overt hyperkeratosis, typically develops within the first three years of life. Keratosis also affects other sites such as elbows and knees. Most PLS patients display both periodontitis and hyperkeratosis. Some patients have only palmoplantar keratosis or periodontitis, and in rare individuals the periodontitis is mild and of late onset. The PLS locus has been mapped to chromosome 11q14-q21 (refs 7, 8, 9). Using homozygosity mapping in eight small consanguineous families, we have narrowed the candidate region to a 1.2-cM interval between D11S4082 and D11S931. The gene (CTSC) encoding the lysosomal protease cathepsin C (or dipeptidyl aminopeptidase I) lies within this interval. We defined the genomic structure of CTSC and found mutations in all eight families. In two of these families we used a functional assay to demonstrate an almost total loss of cathepsin C activity in PLS patients and reduced activity in obligate carriers.
Collapse
Affiliation(s)
- C Toomes
- Department of Medical Genetics, St. Mary's Hospital, Manchester, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Tassabehji M, Carette M, Wilmot C, Donnai D, Read AP, Metcalfe K. A transcription factor involved in skeletal muscle gene expression is deleted in patients with Williams syndrome. Eur J Hum Genet 1999; 7:737-47. [PMID: 10573005 DOI: 10.1038/sj.ejhg.5200396] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Williams-Beuren syndrome (WS) is a developmental disorder caused by a hemizygous microdeletion of approximately 1.4MB at chromosomal location 7q11.23. The transcription map of the WS critical region is not yet complete. We have isolated and characterised a 3.4 kb gene, GTF3, which occupies about 140 kb of the deleted region. Northern blot analysis showed that the gene is expressed in skeletal muscle and heart, and RT-PCR analysis showed expression in a range of adult tissues with stronger expression in foetal tissues. Part of the conceptual GTF3 protein sequence is almost identical to a recently reported slow muscle-fibre enhancer binding protein MusTRD1, and shows significant homology to the 90 amino-acid putative helix-loop-helix repeat (HLH) domains of the transcription factor TFII-I (encoded for by the gene GTF2I). These genes may be members of a new family of transcription factors containing this HLH-like repeated motif. Both GTF3 and GTF2I map within the WS deleted region, with GTF2I being positioned distal to GTF3. GTF3 is deleted in patients with classic WS, but not in patients we have studied with partial deletions of the WS critical region who have only supravalvular aortic stenosis. A feature of WS is abnormal muscle fatiguability, and we suggest that haploinsufficiency of the GTF3 gene may be the cause of this.
Collapse
Affiliation(s)
- M Tassabehji
- University Department of Medical Genetics, St Mary's Hospital, Manchester, UK.
| | | | | | | | | | | |
Collapse
|
46
|
Bondurand N, Kuhlbrodt K, Pingault V, Enderich J, Sajus M, Tommerup N, Warburg M, Hennekam RC, Read AP, Wegner M, Goossens M. A molecular analysis of the yemenite deaf-blind hypopigmentation syndrome: SOX10 dysfunction causes different neurocristopathies. Hum Mol Genet 1999; 8:1785-9. [PMID: 10441344 DOI: 10.1093/hmg/8.9.1785] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Yemenite deaf-blind hypopigmentation syndrome was first observed in a Yemenite sister and brother showing cutaneous hypopigmented and hyperpigmented spots and patches, microcornea, coloboma and severe hearing loss. A second case, observed in a girl with similar skin symptoms and hearing loss but without microcornea or coloboma, was reported as a mild form of this syndrome. Here we show that a SOX10 missense mutation is responsible for the mild form, resulting in a loss of DNA binding of this transcription factor. In contrast, no SOX10 alteration could be found in the other, severe case of the Yemenite deaf-blind hypopigmentation syndrome. Based on genetic, clinical, molecular and functional data, we suggest that these two cases represent two different syndromes. Moreover, as mutations of the SOX10 transcription factor were previously described in Waardenburg-Hirschsprung disease, these results show that SOX10 mutations cause various types of neurocristopathy.
Collapse
Affiliation(s)
- N Bondurand
- Génétique Moléculaire et Physiopathologie, INSERM U468 et Laboratoire de Biochimie et Génétique Moléculaire, AP-HP, Hôpital Henri Mondor, 94010 Créteil Cedex, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Hockenhull EL, Carette MJ, Metcalfe K, Donnai D, Read AP, Tassabehji M. A complete physical contig and partial transcript map of the Williams syndrome critical region. Genomics 1999; 58:138-45. [PMID: 10366445 DOI: 10.1006/geno.1999.5815] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Williams syndrome (WS) is a contiguous gene syndrome caused by hemizygosity for a chromosomal deletion at 7q11.23. The range of phenotypes includes mental retardation, dysmorphic facies, heart abnormalities, short stature, a specific cognitive profile, hyperacusis, and infantile hypercalcaemia. To identify all the deleted genes, we have constructed a detailed physical map and complete BAC/PAC contig of the critical region, extending a distance of approximately 2 Mb and delimited by the nondeleted markers D7S1816 and D7S489A. Somatic cell hybrids of WS patients were made and used to define the centromeric and telomeric deletion breakpoints, enabling the size of the WS deletion to be defined as approximately 1.4 Mb. Genes previously mapped to the region have been located on the contig, and we have isolated eight transcripts, two of which have been characterized as the genes CPETR1 and CPETR2. This contig and expressed sequence map will form the basis for the construction of a complete transcription map of the deleted region and will enable genotype-phenotype correlations to be attempted to identify the individual components of WS.
Collapse
Affiliation(s)
- E L Hockenhull
- University Department of Medical Genetics and Regional Genetics Service, St. Mary's Hospital, Manchester, M13 0JH, United Kingdom
| | | | | | | | | | | |
Collapse
|
48
|
Wu CL, Roz L, McKown S, Sloan P, Read AP, Holland S, Porter S, Scully C, Paterson I, Tavassoli M, Thakker N. DNA studies underestimate the major role of CDKN2A inactivation in oral and oropharyngeal squamous cell carcinomas. Genes Chromosomes Cancer 1999; 25:16-25. [PMID: 10221335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Loss of CDKN2A expression was demonstrated by immunohistochemistry in 87% of oral and oropharyngeal squamous cell carcinoma (OSCC) primary tumor samples. By contrast, DNA studies showed a much lower frequency of loss of the CDKN2A gene. Point mutations and promoter methylation of CDKN2A were seen in 7% and 23%, respectively, of primary tumors. Loss of heterozygosity analysis using a dense set of 9p markers showed allelic imbalance that included CDKN2A in only 31% of samples, but a further 47% showed loss at loci near CDKN2A with apparent retention of CDKN2A. No tumor with any allelic imbalance expressed CDKN2A, whether or not the imbalance appeared to involve the CDKN2A locus. We interpret these data as showing partially overlapping deletions on the two 9p homologues, with homozygous deletion of CDKN2A masked by amplification of contaminating stromal material. Our data show that inactivation of the CDKN2A gene products is a near-universal step in the development of oral and oropharyngeal squamous cell carcinomas, and we suggest that homozygous deletion is the most common mechanism of inactivation. The CDKN2A locus may be particularly prone to deletion because it encodes two unrelated tumor suppressor proteins, CDKN2A (p16INK4a) and p19ARF, and deletion, but not point mutation or methylation, would inactivate both gene products. However, our results also suggest that complex patterns of allelic imbalance in primary squamous carcinomas in general may not provide reliable evidence for the existence of multiple tumor suppressor genes within a single chromosomal region.
Collapse
Affiliation(s)
- C L Wu
- University Department of Medical Genetics, St Mary's Hospital, Manchester, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Wu CL, Roz L, McKown S, Sloan P, Read AP, Holland S, Porter S, Scully C, Paterson I, Tavassoli M, Thakker N. DNA studies underestimate the major role ofCDKN2A inactivation in oral and oropharyngeal squamous cell carcinomas. Genes Chromosomes Cancer 1999. [DOI: 10.1002/(sici)1098-2264(199905)25:1<16::aid-gcc3>3.0.co;2-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|
50
|
Smith SJ, Rucka AK, Berry JL, Davies M, Mylchreest S, Paterson CR, Heath DA, Tassabehji M, Read AP, Mee AP, Mawer EB. Novel mutations in the 1alpha-hydroxylase (P450c1) gene in three families with pseudovitamin D-deficiency rickets resulting in loss of functional enzyme activity in blood-derived macrophages. J Bone Miner Res 1999; 14:730-9. [PMID: 10320521 DOI: 10.1359/jbmr.1999.14.5.730] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Pseudovitamin D-defiency rickets (PDDR) is an autosomal recessive disorder characterized by hypocalcemia, rickets (which are resistant to treatment with vitamin D), and low or undetectable serum levels of 1,25-dihydroxyvitamin D (1,25(OH)2D). The symptoms are corrected with 1,25(OH)2D treatment, and the disease is now believed to result from a defect in the cytochrome P450 component (P450c1; CYP27B1) of the renal 25-hydroxyvitamin D-1alpha-hydroxylase (1-OHase). We have studied genomic DNA from three families with PDDR and have identified the same homozygous mutation in the P450c1 gene in two of the index cases, causing a frameshift in exon 8, resulting in a premature stop codon in the heme-binding domain. The two cases in the third kindred were compound heterozygotes with missense mutations in exons 6 and 9. We have also identified a C/T polymorphism in intron 6 of the P450c1 genomic DNA. Interferon gamma-inducible 1-OHase activity in blood-derived macrophages was shown by 1,25(OH)2D synthesis in all control cells tested (37-184 fmol/h/106 cells) and those from the PDDR family parents (34-116 fmol/h/106 cells) but was totally absent from the patients' cells, indicating a defect in their macrophage 1-OHase, similar to the presumed renal defect. The assumption of similarity between the renal and macrophage P450c1 was supported by our ability to clone a 514 bp sequence, including the heme-binding region of the macrophage P450c1 cDNA from controls, which was identical to that published for both the renal and keratinocyte P450c1 cDNAs.
Collapse
Affiliation(s)
- S J Smith
- University Department of Medicine, Manchester Royal Infirmary, Manchester, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|