[Folate consumption in the preconception period of Sicilian pregnant women and their knowledge about the prevention of neural tube defect by folate supplementation]. / Assunzione di folati in epoca periconcezionale in gravide siciliane e loro conoscenza della prevenzione dei DTN tramite somministrazione di folati.

BACKGROUND AND AIMS: To define the frequency of Sicilian pregnant women taking folic acid during the periconceptional period (three months before and two months after conception) and how many are familiar with the preventive effects of folic acid on NTD. METHODS: 987 pregnant women from eastern Sicily, mainly with low incomes and low levels of education, most with secondary school certificates, underwent biochemical screening for Down's syndrome and NTD in the second trimester of pregnancy. RESULTS: An anencephalous fetus was diagnosed (frequency 0.1%) in a non-risk couple who had not taken folic acid during the periconceptional period: 4.1% (41 cases) of pregnant women reported having taken folic acid before pregnancy and 12.3% (122) during the first two months of pregnancy: five (0.5%) took folic acid during the periconceptional period (three months before conception and two months after). None of the 5 patients with a positive family history of NTD had taken folic acid. In all 122 cases the intake of folic acid supplements during pregnancy started after the positive results of the pregnancy test or echographic evidence of pregnancy, namely between the fifth and eighth week of pregnancy. Only the 5 pregnant women (0.5%) who took folic acid during the periconceptional period were aware of the possibility of preventing NTD through supplements of this vitamin. CONCLUSIONS: Greater efforts must be made to increase periconceptional use of folic acid for the prevention of NTD in pregnant women in Sicily.

A novel mechanism for the origin of supernumerary marker chromosomes.

A ring chromosome 3 and a 47th chromosome formed by the portions of 3p and 3q distal to the r(3) breakpoints were found in a girl with mental retardation and minor facial anomalies. The supernumerary chromosome 3, rea(3), had a primary constriction inside its 3p portion (3p23) and was consistently stable both in lymphocytes and fibroblasts. In situ hybridization with alphoid probes revealed that the r(3) maintained its wild-type-centromere, whereas the rea(3) showed no alphoid-related signals. This case and a similar one recently reported demonstrate that acentric fragments can acquire a new centromere and become stable, and that supernumerary marker chromosomes can also originate by the junction of the acentric portions distal to the centric region forming a ring. The possibility of such a chromosome segregating will depend on its ability to (re)activate a new centromere.

Trisomy 8 syndrome owing to isodicentric 8p chromosomes: regional assignment of a presumptive gene involved in corpus callosum development.

Two patients with trisomy 8 syndrome owing to an isodicentric 8p;8p chromosome are described. Case 1 had a 46,XX/46,XX,-8,+idic(8)(p23) karyotype while case 2, a male, had the same abnormal karyotype without evidence of mosaicism. In situ hybridisation, performed in case 1, showed that the isochromosome was asymmetrical. Agenesis of the corpus callosum (ACC), which is a feature of trisomy 8 syndrome, was found in both patients. Although ACC is associated with aneuploidies for different chromosomes, a review of published reports indicates that, when associated with chromosome 8, this defect is the result of duplication of a gene located within 8p21-pter. Molecular analysis in one of our patients led us to exclude the distal 23 Mb of 8p from this ACC region.

Cytogenetic analysis in congenital hypothyroidism.

In order to evaluate the possible role of genetic factors in the pathogenesis of congenital hypothyroidism (CH), we investigated the occurrence of chromosome aberrations in a consecutive series of 47 patients with CH and 208 matched healthy controls. No abnormal karyotype was found in CH patients. In 5 CH patients and in 3 healthy controls a number of heterochromatin variants was detected. Although chromosomal variants are devoid of phenotypic effects, the frequency of these variants was higher in CH patients than in the control group (10.6% vs 1.4%, p less than 0.005). These findings suggest that the association of congenital hypothyroidism with chromosomal variants may reflect more than chance concurrence.

Reproductive hormone studies in three subjects with a Robertsonian translocation.

The reproductive hormone function was investigated in three subjects, two brothers and one unrelated patient, with a Robertsonian translocation, who had come to us because of infertility. Basal levels of LH, FSH, testosterone, 17-beta-estradiol and prolactin were repeatedly measured by radioimmunoassays. In addition, clomiphene citrate, synthetic LH-RH, hCG and TRH tests were carried out. Karyotypes complemented by G-banding and C-banding, repeated semen analyses, and testicular biopsies were also obtained. The karyotype of all three subjects was 45, XY-13, -14, +t(13; 14) (p11; q11). Semen analyses showed oligozoospermia, and reduced or reduced/normal sperm motility. In addition, a high percentage of atypical forms was present in all three subjects. Reproductive hormone measurements in our three patients were substantially normal. Only one of the two brothers exhibited slightly low LH and testosterone levels. Both brothers also had elevated estradiol levels. Gonadotropin and testosterone responses to respective provocative stimuli, as well as prolactin elevation following TRH, were normal. In conclusion, the semen abnormalities observed in these three subjects with Robertsonian translocation appear to be responsible for their impaired fertility. However, the reason why some carriers of the same translocation are fertile and some others are subfertile or infertile remains unclear. It might be speculated that an individual genetic variability is responsible for different degrees of spermatogenic failure, accompanied, in more severe cases, also by reproductive hormone disorders.