[Effectiveness of congenital abnormalities prophylaxis in Belarus]. / Effektivnost' profilaktiki vrozhdennykh porokov razvitiia v Belarusi.

Congenital and hereditary pathology in Belarus is the leading cause of infant morbidity and mortality. The prevention of this pathology is the most significant strategy in such circumstances. Among the preventive techniques employed are protection of population from additional anthropogenic factors, vitaminization of population, timely and state-of-the-art medical genetic counseling, and prenatal diagnostics.

[Down syndrome and ionizing radiation: causal effect or coincidence]. / Sindrom Dauna i ioniziruiushchaia radiatsiia: prichinno-sledstvennaia sviaz' ili sluchainaia zavisimost'.

Annual and monthly prevalence of Down's Syndrome has been analyzed in Belarus for a 19-year period (1981 to 1999). The distribution of 2786 DS cases during this period showed no significant long-term prevalence trend. Meanwhile, 2 marked increases of DS prevalence were registered in 1987 and 1990. The most remarkable annual increases were observed in 1987 in Minsk city, in Vitebsk oblast (considered as contamination-free administrative district) and in Minsk oblast (partially contaminated area), data not shown in the text. Much more marked and significant increases were recorded in January 1987, in Minsk city, Gomel oblast and Minsk oblast. However it is impossible to establish a causal relationship between these clusters of DS and exposure to the Chernobyl fallout, at a geographical level. The presence of such a cluster 9 months after the explosion in one of the most exposed area (Gomel oblast) should incite to careful conclusions and prompt further studies.

[Incidence of developmental defects in human embryos in the territory of Byelarus after the accident at the Chernobyl nuclear power station]. / Chastota porokov razvitiia u émbrionov cheloveka na territorii Belorussii posle avarii na Chernobyl'skoi AES.

The incidence of developmental abnormalities (DA) among 5 to 12-week human embryos collected in Minsk during abortions before the Chernobyl' accident was compared to that in Minsk, Mogilev, and southeastern districts of Gomel' and Mogilev regions before and after the accident. The incidence of DA among human embryos from the most radionuclide-contaminated rural regions of Byelarus exceeds that of the control group and of the urban population after the Chernobyl' accident by a factor of 1.5-2. The mutagenic effect of irradiation is the most probable cause of the increased DA frequency. These data suggest that recording of DA in embryos obtained by medical abortions is a new promising approach to the monitoring of genetic consequences of irradiation in human populations.

[Clinical and genetic analysis of the Townes-Brocks syndrome]. / Klinicheskii i geneticheskii analiz sindroma Taunsa-Broksa.

Due to the performed analysis of data from literature and the author's observations of the Taunse-Brock's syndrome a wide variability of phenotypic manifestations is shown, the diagnostic criteria of syndrome are determined, its autosomic-dominant inheritance with complete penetrance is confirmed.

[Pathomorphologic verification of the prenatal diagnosis of developmental defects in trimester II fetuses]. / Patomorfologicheskaia verifikatsiia prenatal'nykh diagnozov porokov razvitiia u plodov II trimestra.

153 foetuses were studied obtained after the artificial abortion for genetical indications. The scheme of the material investigation is given. Isolated, systemic and multiple defects were found in 39.0, 12.1 and 48.9%, respectively, and the contribution of the syndrome forms in the multiple developmental disturbances was 60.9%. The interruption of the pregnancy in 2% of cases was assessed as unfounded: as a consequence of hyperdiagnosis and in cases of treatable defects. The frequency of the discrepancy between prenatal and pathology diagnoses was 31.8% including hyperdiagnosis of the defect (1.3%), nosological disagreement (13.3%), the lack of diagnosis of the additional defects detectable during II trimester by present ultrasound methods (17.2%). The efficacy of the work of the prenatal diagnostic centre is, according to the authors, the number of justified interruptions of pregnancy (98% in this study).

[The contribution of genetic factors to perinatal pathology and infant mortality]. / Vklad geneticheskikh faktorov v perinatal'nuiu patologiiu i detskuiu smertnost'.

The authors consider the contribution made by genetic factors to perinatal and infant mortality on the basis of many-year studies performed in the Minsk Teratology Center and analysis of the data available in the literature. In 1972-1984 there was an increase in the incidence of congenital malformations among deceased children. Genetic factors predispose to at least 7-8% postimplantation embryonal and fetal elimination. Perinatal and neonatal mortality is caused by congenital malformations in 19.1 and 37% of cases, respectively. A genetic analysis has indicated that 23.2% of them are induced by genic, chromosomal, and genomic mutations and 51.0% are caused multifactorially. The prevention of genetically determined perinatal mortality is most effective in implementing the screening programs for detection of heterozygous carriage along with subsequent prospective examination and prenatal diagnosis.

[Aplasia of the radius and mechanisms of deformity of the arm]. / Aplaziia luchevoi kosti i mekhanizmy deformatsii verkhnei konechnosti.

A complex study (roentgenographic, arteriographic, anatomic, anthrometric and microscopic) of 16 upper extremities of stillborn and deceased infants with aplasia and hypoplasia of the radius has been carried out. The etiologic factors of the defect were chromosomal and monogenic mutations and multifactor causes. It has been demonstrated that: 1) in cases of reduction of the radius the structure of the arteries, nerves and muscles in destroyed mostly in the radial border of the forearm and hand; 2) the severity of the changes in the anatomic depends on the type of the defect; 3) the pathomorphologic manifestations of the forms of the defect characterized by the same severity are mostly similar. The mechanisms of deformations of the hand in aplasia (hypoplasia of the radius) are discussed.

[The prospective directions of research in teratology]. / Perspektivnye napravleniia issledovanii v teratologii.

Unsolved problems of modern teratology are discussed. The monitoring of the congenital malformation incidence is one of the variants of evaluation and control of the mutation pressing in the population. The investigation of human foetuses obtained in artificial abortions may be very helpful in this respect. The investigation of the phenotypical manifestations of malformations in the human prenatal ontogenesis and the use of the results for the creation of notion on the malformation morphogenesis seems to be perspective. The definition of the tissue dysplasias and their classification (dystopia, dyssynchronia, hamartomas) are given. The issue of the tissue malformations during the postnatal development is not similar. They may be asymptomatic, or to disturb the function of the organ concerned, or to predispose to chronic inflammation or neoplastic growth.

[A new case of the "double hypophysis--multiple congenital developmental defects" complex]. / Novoe nabliudenie kompleksa "udvoenie gipofiza--mnozhestvennye vrozhdennye poroki razvitiia".

The results from clinical and genetic analysis of a case with "double hypophysis--multiple malformations" complex and data from literature are presented. The complex is supposed to be a consequence of "midline" field disturbance with multifactorial mode of inheritance.

[Changes in the protein spectrum of human kidney anlagen]. / Izmenenie belkovogo spektra zachatkov pochki u cheloveka.

Extracts of metanephros were studied using two-dimensional electrophoresis in human embryos at the age of 7 to 21 week of intrauterine development. Electrophoregrams show 160 to 190 protein fractions. Fractions have been identified which corresponded to actin, albumin, alpha-chain of tropomyosin, light chains of myosin. The tropomyosin zone fractions were subject to greatest changes during development. Other zones of the embryonic kidney electrophoretogram displayed, predominantly, quantitative changes of polypeptides.

[The main etiologic groups of congenital developmental defects and the problems of diagnosis and thanatogenesis]. / Osnovnye étiologicheskie gruppy vrozhdennykh porokov razvitiia i nekotorye voprosy diagnostiki i tanatogeneza.

The proportion of congenital developmental defects (CDD) in children decreased in perinatal or early age is increasing. According to national and foreign data this figure is in the range of 21-41%. The etiologic structure of CDD for the last 5 years (1980-1984) basing on the data from the Minsk Teratologic Center has not practically changed. As in the previous 5 years, 50.8% of CDD belong to multifactorial ones, 14.3% are due to single gene mutations (8.4% of them are inherited according to dominant type and 5.9%--according to recessive type). Chromosome and gene mutations caused 7.9% of CDD. About 2% of CDD are induced by the effect of environmental factors on the embryo (less frequently on the fetus). Etiology of 25.1% of CDD is not clear.

[Genetics of Patau's syndrome (an analysis of 59 families)]. / Genetika sindroma Patau (analiz 59 semei).

Different parental translocations were observed in 11 out of 59 families where a child with Patau's syndrome was born. All cases, except for one with t(13; 18) (q14; q23) in the father, revealed the Robertsonian translocations. In most cases there were t(13; 14). The t(13; 15) and t(13; 13) translocations were detected in one mother each. The latter woman bore three babies with Patau's syndrome. One boy in this series had trisomy 13 and sporadic translocation t(2; 22) (q31; q13) simultaneously.

[Pathological anatomy of monogenic syndromes of multiple congenital developmental defects]. / Patologicheskaia anatomiia monogennykh sindromov mnozhestvennykh vrozhdennykh porokov razvitiia.

Morphological study, with no selection, is performed of 1106 stillborns and children died before one year of age with congenital malformations (CM), 536 (46.9 +/- 1.5%) among them having multiple CM. Syndrome diagnosis is made in 44.1 +/- 2.1% cases: in 26.9 +/- 1.9% among them these were syndromes of chromosomal and in 17.9 +/- 1.7% syndromes of non-chromosomal etiology. Monogenic hereditary forms among non-chromosomal syndromes were in 42.1 +/- 4.8%. Comparative analysis of frequency and types of CM of various systems in monogenic and chromosomal syndromes and unclassified CM showed that the monogenic syndromes by their phenotypic manifestations are close to the chromosomal syndromes. The uniformity of alterations of certain morphological structures in these syndromes appear to be the consequence of common ways of realisation of both mutant genes in monogenic syndromes and their imbalance in chromosomal syndromes.

[Importance of the diagnosis of congenital developmental defects in the practice of pathologists]. / Znachenie diagnostiki vrozhdennykh porokov razvitiia v praktike patologoanatomov.

Composite studies of 1286 stillborns and infants with congenital malformations (CMF) dying at the age under 1 year conducted in the Teratological Center of Minsk showed that in specialized therapeutic institutions the causes of CMF could be established in at least 70% of the cases. In the infant autopsy materials, 12% of CMF were associated with chromosome pathology, 17% with single gene mutations, over 40% had multifactor determinants and 2.7% were due to teratogenic effects.

[Bowen-Conrad syndrome]. / Sindrom Bouéna-Konradi.

An observation of multiple malformation defects (Bowen-Conradi syndrome) is presented. The main morphological manifestations included: marked prenatal hypoplasia, facial dysplasias, microgeny, clinodactylia of little fingers, hypospadia, cryptorchism, changes in the central nervous system. All the patients with this syndrome die within the first year of life. The disease is inherited by the autosome-recessive type.