Benign Hereditary Chorea of Early Onset Maps to Chromosome 14q

Benign hereditary chorea (BHC) is an autosomal dominant disorder characterized by an early-onset nonprogressive chorea. The early onset and the benign course distinguishes BHC from the more common Huntington disease (HD). Previous studies on families with BHC have shown that BHC and HD are not allelic. We studied a large Dutch kindred with BHC and obtained strong evidence for linkage between the disorder and markers on chromosome 14q (maximum LOD score 6.32 at recombination fraction 0). The BHC locus in this family was located between markers D14S49 and D14S1064, a region spanning ∼20.6 cM that contains several interesting candidate genes involved in the development and/or maintenance of the CNS: glia maturation factor-β, GTP cyclohydrolase 1 and the survival of motor neurons (SMN)-interacting protein 1. The mapping of the BHC locus to 14q is a first step toward identification of the gene involved, which might, subsequently, shed light on the pathogenesis of this and other choreatic disorders

Cancer-prone syndrome of mosaic variegated aneuploidy and total premature chromatid separation: Report of five infants

Five infants (two girls and three boys) from four families all had severe pre- and post-natal growth retardation, profound developmental delay, microcephaly, hypoplasia of the brain with Dandy-Walker complex or other posterior fossa malformations, and developed uncontrollable clonic seizures. Four infants developed Wilms tumors, and one showed cystic lesions in bilateral kidneys. All five infants showed variegated mosaic aneuploidy in cultured lymphocytes. In two infants whose chromosomes were prepared by us, 48.5%-83.2% lymphocytes showed total premature chromatid separation (PCS). Their parents had 3.5%-41.7% of their lymphocytes in total PCS. The remaining three infants and their parents, whose chromosomes were prepared at outside laboratories, tended to show lower frequencies of total PCS. Another five infants reported with the disorder were reviewed together with the five infants we described. Together, their clinical and cytogenetic manifestations were similar enough to suggest a syndrome. Seven of the 10 infants developed proven or probable Wilms tumors. The age at diagnosis of the tumors was younger than usual at 2-16 months. The tumors were bilateral in four infants and unilateral in three infants, and cystic changes were present in six infants. Two infants developed botryoid rhabdomyosarcoma. The carriers of the syndrome are thus liable to tumorigenesis. The possible role of mitotic checkpoint defects, proven in two infants with the syndrome (Matsuura et al. [2000: Am J Hum Genet 69:483-486]), was discussed in connection with tumor development and progression

Similar phenotype characteristics comparing familial and sporadic premature ovarian failure

Objective: Premature ovarian failure (POF) is characterized by secondary amenorrhea before the age of 40 years, along with repeated increased follicle-stimulating hormone and low estrogen concentrations. POF is considered a complex genetic disease with a familial presentation in 12% to 50% of cases. POF may originate from different genes and various gene-environment interactions. The aim of this study was to identify possible differences in phenotype comparing women with familial and women with sporadic POF. Methods: A multicenter study was initiated in the Netherlands using standardized phenotyping. For each woman, medical history, menstrual cycle, and fertility and smoking status were assessed and a standardized examination was performed. Based on a detailed three-generation family history, women were identified as having either familial (defined as having at least one relative with POF) or sporadic POF. Results: A total of 58 familial cases and 142 sporadic cases of POF were identified. Maternal age at menopause was significantly lower in the women with familial compared with the women with sporadic POF (41.0 +/- 7.5 and 49.7 +/- 2.6 y, respectively; P <0.001). Sex hormone-binding globulin concentration was significantly higher in the women with familial than in the women with sporadic POF (73.6 +/- 37.1 and 55.2 +/- 26.9 nmol/L, respectively; P = 0.002). All other characteristics, such as parity, bone mineral density, and serum follicle-stimulating hormone and lipid levels were similar, as was the incidence of autoimmunity and cytogenetic abnormalities. Conclusions: Familial and sporadic POF do not differ in phenotype except for maternal menopause age and sex hormone-binding globulin concentration. Future studies are needed to unravel the genotype-phenotype interactions in POF

Attitudes and distress levels in women at risk to carry a BRCA1/BRCA2 gene mutation who decline genetic testing

Genetic testing enables women at risk for hereditary breast and/or ovarian cancer to find out whether they have inherited the gene mutation, and if so, to opt for undergoing frequent surveillance and/or prophylactic surgery. However, the option to know about one's genetic status is not always seen as a benefit by women at risk. Motives for declining genetic testing were explored in 13 women at 25% or 50% risk to be a BRCA1/BRCA2 mutation carrier, who participated in a surveillance program for breast/ovarian cancer (the non-tested group). We hypothesized that high anxiety might be an important motive to decline testing. In addition, we investigated whether the non-tested group differed from a reference group of women who did undergo the test (tested group; n = 85) with regard to biographical factors, experience with cancer in relatives, and personality traits. Most non-tested women (10/13) were satisfied with participating in the surveillance program. Four reported to feel emotionally unprepared to cope with the consequences of testing. Compared with the tested group, the non-tested women had similar mean distress levels (which were not high), but a higher education level, they were more often childless, showed more reluctance towards prophylactic surgery, were younger when first confronted with a relative affected with breast/ovarian cancer, and were longer aware of the genetic nature of the disease. This study showed that women were more likely to have thoroughly reflected on their decision not to undergo genetic testing, than to deny the whole issue due to high anxiety. Being confronted at a relatively young age with breast/ovarian cancer in a relative, and being aware of the genetic risk for a many years, may have resulted in the risk for cancer becoming an integrated part of their lives. However, generalization of these results to women who neither underwent the test nor participated in a surveillance program should be considered with cautio

Screening and Diagnosis for the Fragile X Syndrome among the Mentally Retarded: An Epidemiological and Psychological Survey

SummaryThe fragile X syndrome is an X-linked mental retardation disorder caused by an expanded CGG repeat in the first exon of the fragile X mental retardation (FMR1) gene. Its frequency, X-linked inheritance, and consequences for relatives all prompt for diagnosis of this disorder on a large scale in all affected individuals. A screening for the fragile X syndrome has been conducted in a representative sample of 3, 352 individuals in schools and institutes for the mentally retarded in the southwestern Netherlands, by use of a brief physical examination and the DNA test. The attitudes and reactions of (non)consenting parents/guardians were studied by (pre- and posttest) questionnaires. A total of 2, 189 individuals (65%) were eligible for testing, since they had no valid diagnosis, cerebral palsy, or a previous test for the FMR1 gene mutation. Seventy percent (1, 531/2, 189) of the parents/guardians consented to testing. Besides 32 previously diagnosed fragile X patients, 11 new patients (9 males and 2 females) were diagnosed. Scoring of physical features was effective in preselection, especially for males (sensitivity .91 and specificity .92). Major motives to participate in the screening were the wish to obtain a diagnosis (82%), the hereditary implications (80%), and the support of research into mental retardation (81%). Thirty-four percent of the parents/guardians will seek additional diagnostic workup after exclusion of the fragile X syndrome. The prevalence of the fragile X syndrome was estimated at 1/6,045 for males (95% confidence interval 1/9, 981-1/3, 851). On the basis of the actual number of diagnosed cases in the Netherlands, it is estimated that > 50% of the fragile X cases are undiagnosed at present