Loss-of-function mutations in the cathepsin C gene result in periodontal disease and palmoplantar keratosis.

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.

Association of angiotensin converting enzyme gene (I/D) polymorphism with hypertension and type 2 diabetes.

OBJECTIVES: This study was conducted to determine the association of insertion/deletion (I/D) polymorphism of the ACE gene in hypertensive and T2DM subjects in Egyptian population. BACKGROUND: The deletion (D) allele of the angiotensin-converting enzyme (ACE) gene has been studied in relation to hypertension and type 2 diabetes mellitus (T2DM) with contradictory results which might be due to ethnic and geographical variations. METHODS: A total of 85 subjects participated in this study; hypertension (Group 1); type 2 diabetes mellitus (Group 2) and controls (Group 3). Written informed consent was obtained. for each subject: age, sex, diabetes duration and the drugs used, blood pressure (systolic and diastolic), and lipid profile. Genotyping was performed by polymerase chain reaction (PCR). RESULTS: The frequency of DD genotype was significantly higher in hypertensive (60 %) and diabetic patients (68 %) compared to controls (33.3 %) (p=0.04, p=0.01 respectively). The DD genotype (vs DI and II genotype) in the hypertensive and diabetic groups is associated with increased risk of hypertension and/or diabetes. OR=3.00; 95%, Cl = 0.993-9.067; OR=4.250; 95%, Cl = 1.234-14.63 respectively). The D allele was more frequent in hypertensive (77.5 %) and diabetic patients (82 %) compared to controls (52.4 %) (p=0.004 and 0.002 respectively). The D allele (vs the I allele) is associated with increased risk of hypertension and diabetes OR=3.13, 95%Cl=1.405-6.978; OR= 4.14, 95% CI= 1.615-10.622 respectively). CONCLUSION: The DD genotype and the D allele are associated with hypertension and type 2 diabetes in Egyptian patients (Tab. 5, Fig. 1, Ref. 32).

The use of DNA markers for carrier detection and prenatal diagnosis of haemophilia A in Egyptian families.

Haemophilia A is the most common inherited X-linked recessive bleeding disorder. The aim was to investigate the usefulness of two DNA markers in linkage analysis, one intragenic BCL1 affecting restriction site in intron 18, and is detected as restriction fragment length polymorphism (RFLP), and one extragenic variable number of tandem repeat (VNTR) locus DXS52 (St14) to formulate an informative and accurate carrier detection and prenatal diagnosis. The study included 46 families with at least one child affected with haemophilia A, and 30 unrelated normal females as control group. Polymerase chain reaction (PCR) and restriction enzyme analysis were used to study the polymorphism in BCL1, and long-distance PCR for detection of VNTR (ST14) alleles. The incidence of BCL1 (+) allele was 74%, 72% and 60% in patients, mothers and control group, respectively. Expected heterozygosity for BCL1 was 40% in mothers of affected cases compared with 48% in the female control group. However, observed heterozygosity was found to be 48% in the mothers of affected cases, compared with 60% in the control group. Thus, 48% of the studied families are informative for this marker alone. Nine different alleles of VNTR (St14) were observed in mothers and six alleles in affected cases and six in the control group. The most prevalent alleles were 1300 bp (45.5% and 34%) and 700 bp (13.6% and 20%) in patients and their mothers, respectively. Observed heterozygosity in mothers was 41% compared with 43.3% in controls. The combined use of both BCL1 and St14 markers raised the informative rate to 63.6%. Carrier detection and prenatal diagnosis is possible in haemophilia A families using both DNA markers. We suggest screening haemophilic families first for BCL1 polymorphism followed by analysis of St14 locus.

Genome wide array-CGH and qPCR analysis for the identification of genome defects in Williams' syndrome patients in Saudi Arabia.

BACKGROUND: Williams-Beuren Syndrome (WBS) is a rare neurodevelopmental disorder characterized by dysmorphic features, cardiovascular defects, cognitive deficits and developmental delay. WBS is caused by a segmental aneuploidy of chromosome 7 due to heterozygous deletion of contiguous genes at the long arm of chromosome 7q11.23. We aimed to apply array-CGH technique for the detection of copy number variants in suspected WBS patients and to determine the size of the deleted segment at chromosome 7q11.23 in correlation with the phenotype. The study included 24 patients referred to the CEGMR with the provisional diagnosis of WBS and 8 parents. The patients were subjected to conventional Cytogenetic (G-banding) analysis, Molecular Cytogenetic (Fluorescent In-Situ Hybridization), array-based Comparative Genomic Hybridization (array-CGH) and quantitative Real time PCR (qPCR) Techniques. RESULTS: No deletions were detected by Karyotyping, however, one patient showed unbalanced translocation between chromosome 18 and 19, the karyotype was 45,XX, der(19) t(18;19)(q11.1;p13.3)-18. FISH technique could detect microdeletion in chromosome 7q11.23 in 10/24 patients. Array-CGH and qPCR confirmed the deletion in all samples, and could detect duplication of 7q11.23 in three patients and two parents. Furthermore, the size of the deletion could be detected accurately by both array-CGH and qPCR techniques. Three patients not showing the 7q11.23 deletion were diagnosed by array-CGH to have deletion in chr9p13.1-p11.2, chr18p11.32-p11.21 and chr1p36.13. CONCLUSION: Both FISH and array-CGH are reliable methods for the diagnosis of WBS; however, array-CGH has the advantage of detection of genome deletions/ duplications that cannot otherwise be detected by conventional cytogenetic techniques. Array-CGH and qPCR are useful for detection of deletion sizes and prediction of the interrupted genes and their impact on the disease phenotype. Further investigations are needed for studying the impact of deletion sizes and function of the deleted genes on chromosome 7q11.23. TRIAL REGISTRATION: ISRCTN ISRCTN73824458. MOCY-D-16-00041R1. Registered 28 September 2014. Retrospectively registered.

Molecular characterization of beta-thalassemia in Egyptians.

We sought to determine the spectrum of mutations producing beta-thalassemia in Egypt using genomic PCR and a variety of mutation-screening procedures. Thirty-four beta-thalassemia and three Hb S/beta-thalassemia patients originating from different regions of Egypt were studied, and the causative mutation was found in 69 of 71 (97%) beta-thalassemia genes. Four mutations accounted for 78% of beta-thalassemia genes in this population; IVS-1, nt 110 (41%), IVS-1 nt 6 (13%), IVS-1, nt 1 (13%), and IVS-2, nt 848 (11%). The latter allele, a C-A mutation at the third nucleotide of an acceptor site consensus sequence, has been described previously only in one Egyptian, one Iranian, one Tunisian, and one Black American patient. Nine other alleles each accounted for 1-3% of beta-thalassemia genes. Among these was one codon 27 allele (Hb Knossos), two frameshift 106/107 alleles previously seen only in a Black American, and a rarely observed mutation in the distal promoter region of the beta-globin gene, -87 (C-A). Our results suggest that from a molecular genetic standpoint a beta-thalassemia prevention program based on carrier screening and prenatal diagnosis can be implemented in Egypt. In couples at risk for beta-thalassemia, the causative mutation should be identifiable in both members in 92% and in one member in the remaining 8%.

Identification of Mediterranean beta-thalassemia mutations by reverse dot-blot in Italians and Egyptians.

beta-Thalassemia is a significant public health problem in Egypt where over 1000 of the annual 1.5 million newborns are expected to be affected with this disorder. A preventive program of the disease should be multifaceted with its technical component based on carrier screening and prenatal diagnosis through mutation detection. In addition, it should have an information and educational component with the aim of increasing public awareness of the disease. Proper selection of the technique(s) to be utilized in such a program is highly important. The appropriate technique to be used in screening should be reliable, simple and cost effective. It should also circumvent the problem of marked heterogeneity of the disease in Egypt. The reverse dot-blot technique has been used in the present study for the characterization of mutations in 138 Italian and 108 Egyptian thalassemia chromosomes, confirming its reliability as a screening method. The technique is now in routine use for thalassemia diagnosis in the Microcitemia Center of the Galliera Hospital in Genoa, Italy. Based on these results, we recommend the reverse dot-blot method as the technique of choice in the preventive program of this disease in Egypt.