Prevalencia de malformaciones congénitas al nacer y factores asociados en Isla de Pascua, Chile: 1988-1998 / Prevalence of congenital malformations and associated factors in Easter Island, Chile

Background: Consanguinity plays an important role in the genetic etiology of congenital malformations. In Easter Island the degree of consanguinity could be higher than in continental Chile. Therefore the study of the prevalence of congenital malformations in this island seems worthwhile. Aim: To study the prevalence of congenital malformations at birth in Easter Island. Material and methods: A review of personal and family features of all children born alive between 1988 and 1998 in the Rapa Nui Hospital of Easter Island. Results: During the study period, 772 newborns were reviewed and 22 were found to have congenital malformations. Among the latter, birth weight fluctuated between 3001 and 4000 g and the male/female ratio was 0.54. No differences in maternal age between children with and without malformations was observed. Heart and circulatory malformations, hemangiomas and Down syndrome were the predominant malformations. Conclusions: The prevalence of congenital malformations at birth in Easter Island is similar to that of continental Chile. No neural tube defects were detected in this sample

A hemizygous short tandem repeat polymorphism 3' to the human phosphoglycerate kinase gene.

The human phosphoglycerate kinase (PGK) gene is located within Xq11-Xq13, a region implicated in genitourinary diseases including: prostate cancer, androgen insensitivity, perineal hypospadias, and other genetic abnormalities. The PGK gene and the androgen receptor gene are in linkage disequilibrium. PGK has been mapped extensively for nuclease-sensitive sites, methylation sites, and flanking DNA sequences. A PGK-associated BstXI polymorphism has been used to determine clonality of neoplastic tissues. Using fluorescent PCR product analysis and DNA sequencing, we discovered that a short tandem repeat (STR) in the 3' flanking region of the PGK gene is polymorphic. Among 231 individuals, there were nine distinct alleles, including eight based on variations in the number of TATC repeats. The PGK STR demonstrated hemizygosity, consistent with its X-chromosomal location and with an absence of cross-hybridizing autosomal homologs. The polymorphic PGK STR shows promise for rapid investigation of neoplastic clonality, for personal identification, and for studies of inherited predisposition to urologic disorders.

Associated malformations in infants and fetuses with upper or lower neural tube defects.

The paper describes associated malformations in infants born with neural tube defects (N = 3,809) from three large malformation registers and in fetuses aborted because of a diagnosed neural tube defect (N = 748) from two of the registers. In infants, upper spina bifida and encephalocele are more often associated with non-neural malformations than anencephaly or lower spina bifida. Aborted fetuses with spina bifida or encephalocele have associated malformations registered more often than infants with those neural tube defects, but the opposite is true for anencephaly. The degree of detail of the investigation of an aborted specimen or a perinatally dead infant will contribute to such differences but they can also depend on the fact that prenatal detection may be facilitated by the simultaneous presence of other malformations like body wall defects. Also, fetuses with many malformations may be more prone to abort spontaneously late in pregnancy. Variable prenatal diagnosis may, therefore, explain population differences in the pattern of associated malformations. The type of associated malformation differs with the level of the neural tube defect: this could be due to different causal mechanisms or be a question of cranio-caudal level and/or timing. For limb reduction defects, however, we did not find any association between upper limb and upper neural tube defects or lower limb and lower neural tube defects. These findings together with other epidemiological data support the idea that upper and lower neural tube defects may have different significance in epidemiological studies and should be treated separately.

Autosomal recessive disorders among Arabs: an overview from Kuwait.

Kuwait has a cosmopolitan population of 1.7 million, mostly Arabs. This population is a mosaic of large and small minorities representing most Arab communities. In general, Kuwait's population is characterized by a rapid rate of growth, large family size, high rates of consanguineous marriages within the Arab communities with low frequency of intermarriage between them, and the presence of genetic isolates and semi-isolates in some extended families and Bedouin tribes. Genetic services have been available in Kuwait for over a decade. During this time it has become clear that Arabs have a high frequency of genetic disorders, and in particular autosomal recessive traits. Their pattern is unique and some disorders are relatively common. Examples are Bardet-Biedl and Meckel syndromes, phenylketonuria, and familial Mediterranean fever. A relatively large number of new syndromes and variants have been delineated in Kuwait's population, many being the result of homozygosity for autosomal recessive genes that occurred because of inbreeding. Some of these syndromes have subsequently been found in other parts of the world, negating the concept of the private syndrome. This paper provides an overview of autosomal recessive disorders among the Arabs in Kuwait from a personal perspective and published studies, and highlights the need for genetic services in Arab countries with the goal of prevention and treatment of genetic disorders.

Natural history of the recombinant (8) syndrome.

The recombinant 8[Rec(8)] syndrome [rec(8), (8qter-->8q22.1::8p23.1-->8qter] is due to a parental inv(8)(8pter-->8p23.1::8q22.1-->8p23.1::8q22+ ++.1-->8qter). All inv(8) parents we have studied were of Hispanic origin. The Rec(8) phenotype consists of a characteristic set of minor facial anomalies, cardiovascular and other major malformations, and moderate to severe mental retardation. The clinical phenotype is relatively consistent in all published cases; however the natural history of the condition has remained unknown. Retrospective and prospective information on 42 propositi, spanning a period from 5 days to 23 years, allowed us to define the natural history of this syndrome, tabulate the frequency and the evolution of phenotypic abnormalities, and share our experience with different therapeutic approaches.

Occidental type cerebromuscular dystrophy: a report of eleven cases.

Occidental type cerebromuscular dystrophy (OCMD) forms a substantial distinct group within congenital muscular dystrophy (CMD). These patients invariably present with amyotrophy, multiple joint contractures, facial muscle involvement, normal or nearly normal intelligence, leukodystrophic appearance on CT scan, and dystrophic changes in muscle.