Multiple endocrine neoplasia 2 in Cyprus: evidence for a founder effect.

PURPOSE: Multiple endocrine neoplasia type 2 (MEN2) affects patients with RET proto-oncogene mutations. This cohort study refers to patients who were diagnosed with familial medullary thyroid carcinoma (MTC) and underwent RET genetic testing in Cyprus between years 2002 and 2017. METHODS AND PATIENTS: Forty patients underwent RET testing by Sanger sequencing of exons 10-11 and 13-16. Genotyping with STR genetic markers flanking the RET gene along with Y-chromosome genotyping and haplogroup assignment was also performed. RESULTS: RET mutations were identified in 40 patients from 11 apparently unrelated Cypriot families and two non-familial sporadic cases. Nine probands (69.2%) were heterozygous for p.Cys618Arg, one (7.7%) for p.Cys634Phe, one (7.7%) for the somatic delE632-L633 and two (15.4%) for p.Met918Thr mutations. The mean age at MTC diagnosis of patients carrying p.Cys618Arg was 36.8 ± 14.2 years. The age of pheo diagnosis ranged from 26 to 43 years and appeared simultaneously with MTC in 5/36 (13.9%) cases. The high frequency of the p.Cys618Arg mutation suggested a possible ancestral mutational event. Haplotype analysis was performed in families with and without p.Cys618Arg. Six microsatellite markers covering the RET gene and neighboring regions identified one core haplotype associated with all patients carrying p.Cys618Arg mutation. CONCLUSIONS: The mutation p.Cys618Arg is by far the most prevalent mutation in Cyprus followed by other reported mutations of variable clinical significance. The provided molecular evidence speculates p.Cys618Arg mutation as an ancestral mutation that has spread in Cyprus due to a possible founder effect.

[Lyme uveitis: 2 case reports]. / Uvéites de Lyme: à propos de 2 observations.

Lyme borreliosis is a zoonosis characterized by great clinical polymorphism. We report 2 cases in patients who presented ocular manifestations: one anterior uveitis in an adult, which resolved under treatment, and one posterior uveitis in a child, whose initial ophthalmologic examination already showed retinal fibrous scars including the macular area. Lyme disease is on the long list of causes that must be discussed in cases of uveitis. The diagnosis is based on a series of epidemiological, clinical, and biological arguments with Western Blot serological profile analysis. Treatment is based especially on intravenous antibiotics.

Systematic screening for diabetic retinopathy with a digital fundus camera following pupillary dilatation in a university diabetes department.

AIMS: Screening for diabetic retinopathy (DR) is highly inadequate in France because of insufficient infrastructure and increasing disease prevalence. We describe the results of the first systematic DR screening programme established in a university diabetes department. METHODS: In this cross-sectional study conducted over 1 year, consecutive adult patients underwent three-field retinal photography with the Topcon TRC NW6S digital fundus camera following pupillary dilatation with Tropicamide 1%. A questionnaire provided information on patients' systemic and ocular history. Glycated haemoglobin (HbA1c) was measured at the screening visit. Two ophthalmologists graded the retinal photographs in a masked fashion. RESULTS: Of 1157 patients attending the diabetes department, 1153 (99.7%)underwent photographic screening. Images were gradable in 96% patients. Diabetic retinopathy was detected in 522 (45%) patients and sight-threatening DR in 167 (14%). Of 704 (61%) patients previously believed to have no DR,254 (34%) screened positive. The presence of DR was associated with age,insulin use and non-Caucasian ethnicity in Type 2 patients, and with duration of diabetes and HbA1c in Type 1 and Type 2 patients. Associated ocular pathologies were diagnosed in 612 (53%) patients. CONCLUSIONS: Our photographic screening programme using pharmacological mydriasis provided a high screening coverage feasible in a hospital setting. We obtained information regarding prevalence and associated risk factors of DR inpatients attending a tertiary care centre. Screening was well accepted by patients and met with no protest from city ophthalmologists. It generated considerable interest among endocrinologists and feedback of results is expected to improve optimization of glycaemic control.

Data on nine STR loci used for forensic and paternity testing in the Greek Cypriot population of Cyprus.

Allele frequencies for the nine STRs included in the AMPFlSTR kit were obtained from a sample of 152 unrelated Greek Cypriot from the Mediterranean island of Cyprus

Characterization and geographic distribution of the low density lipoprotein receptor (LDLR) gene mutations in northwestern Greece.

Familial Hypercholesterolaemia (FH) is a clinical syndrome characterised by elevated serum total cholesterol levels due to an increase in low density lipoprotein (LDL) cholesterol, by tendon xanthomata and clinical manifestations of ischaemic heart disease in early life. Typically, it results from mutations in the low-density lipoprotein receptor (LDLR) gene. So far, over 600 mutations have been reported for the LDLR gene and account for FH. The nature of LDLR gene mutations is different in various ethnicities and has also regional distribution within each ethnicity. Eleven mutations have already been described in the Greek population. This report describes seven LDLR gene mutations accounting for FH in Northwestern Greece (81T>G, 517T>C, 858C>A, 1285G>A, 1352T>C, 1646G>A and 1775G>A) and their geographic distribution. We have recently described one of these mutations (1352T>C) as a novel point mutation in a Greek family originating from Northwestern Greece. Furthermore, two previously identified mutations (81T>C, 1775G>A) were also detected in the Greek FH patients for the first time. The 1775G>A mutation was responsible for all the homozygous patients in our area, indicating a founder effect. These data will favor the development of tailed information and screening programs in Northwestern Greece for the primary prevention of cardiovascular disease in FH patients.

Geographical clustering of low density lipoprotein receptor gene mutations (C292X; Q363X; D365E & C660X) in Cyprus.

In Cyprus, no data are yet available on the frequencies of clinically diagnosed FH patients. Further, until now, familial hypercholesterolaemia in Cyprus had not been studied at the molecular level to determine the nature or frequency of LDLR gene mutations. Being a relatively homogeneous population, we anticipated that a few founder mutations would predominate on the island. In the present study, three previously identified LDLR gene mutations were found to cosegregate with high LDL cholesterol levels in 23 unrelated, clinically diagnosed families with FH. Geographical clustering of each of these LDLR gene mutations was indicated, a phenomenon arising from low migration rates and high inbreeding. The latter cultural practices account for the discovery of a homozygous FH sib pair whose parents are carriers of the same mutation. Microsatellite and intragenic haplotype analysis in this FH population, suggested that the families which shared the same LDLR gene mutation have a common origin. This is supported by their relative geographical distribution. Thirty young FH individuals were also offered presymptomatic diagnosis which should facilitate the prevention of premature coronary artery disease. Finally, results from this study support the suggestion that the formation of tendon xanthomata in FH patients may be under environmental influence. Hum Mutat 15:380, 2000.

Genetic variation and intergenerational FMR1 CGG-repeat stability in 100 unrelated three-generation families from the normal population.

In order to identify genetic factors governing expansion of the CGG repeat in the FMR1 gene and to determine what predisposes or causes a normal stable allele to change to an unstable premutation allele, it is essential to study and understand the basis of normal variation. The aim of this study was to investigate genetic variation and intergenerational stability of the FMR1 CGG-repeat region in 100 unrelated three-generation families from the general population (651 meioses). The number of CGG-repeats in the FMR1 gene was determined in all 750 individuals from the 100 families (a total of 1,132 X-chromosomes), and the allele frequencies and variability were analyzed. Thirty-six different alleles (12-60 repeats) were seen with 30 (45.8%) as the most common allele; overall female heterozygosity was 73%. Most (>96%) of the normal array lengths were less than 40 repeats. Fifteen families with at least one allele equal to or greater than 40 repeats (40-60) were identified; in one of these families there was an increase of one triplet repeat during transmission from a mother to son. These findings, together with future molecular analyses, may provide data to test proposed models that attempt to explain the mutational process and the population dynamics of the triplet repeat region of the FMR1 gene, including the transition from normal to unstable alleles, or to test other putative cis-acting sequences that may be involved with instability in the FMR1 gene.

Greek Cypriot allele and genotype frequencies for Amplitype PM-DQA1 and D1S80 loci.

A sample from the Greek Cypriot population was typed at seven forensically important PCR-based loci: LDLR, GYPA, HBGG, D7S8, GC, HLA-DQA1, and D1S80. The results showed that all loci meet Hardy-Weinberg expectations and that there is no evidence for association of alleles between loci. Allelic frequency distributions at all loci, except HLA-DQA1 and two D1S80 alleles, were similar to those of U.S. Caucasians. Greek Cypriot population databases have been created and can be used for forensic analyses to estimate the frequency of a multiple locus DNA profile.

Novel trinucleotide deletion in Fabry's disease.

We describe the molecular characterization of a novel, in-frame deletion that is located in exon 7 of the alpha-galactosidase A gene in a patient with Fabry's disease. The 3-bp deletion we identified, besides the typical severe clinical features, also expresses diffuse facial telangiectasias, which is a new cutaneous marker of Fabry's disease.

Underexpression of the apolipoprotein E2 and E4 alleles in the Greek Cypriot population of Cyprus.

Apolipoprotein E (APOE) plays an important role in the multifactorial etiology of both cardiovascular disease and Alzheimer's disease. Polymerase chain reaction (PCR) was used to investigate the APOE gene polymorphism in 335 unrelated Greek Cypriots living on the island of Cyprus. For the most common APOE genotypes, the Greek Cypriots followed the general Caucasian European pattern of having higher genotypic frequencies of E3/3, followed by E3/4, and then E2/3. Among the European populations compared, Greek Cypriots exhibited the lowest relative frequency of the E3/4 genotype (12.83%). Also, the relative frequencies of the E2 and E4 alleles in Greek Cypriots were among the lowest around the world (5.4% and 7.0%, respectively). This was also demonstrated by using the complete and the average clustering methods of analysis where the APOE allele relative frequencies in Greek Cypriots were compared to 46 other populations. The Greek Cypriot population in these analyses clustered with populations mainly from south Europe and Japan which have low E2 and E4 allele frequencies. The Greek Cypriot population will be studied further for elucidating the effect(s) and the role of APOE in cardiovascular disease and the APOE4 allele as a possible metabolic factor affecting the rate of expression of both Alzheimer's disease and vascular dementia.