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Biomedical subjects

D Abuelo

Publications and source records attributed to D Abuelo.

17 recordsLinked to original sources
PubMed1995

Identification of 8-dehydrocholesterol (cholesta-5,8-dien-3 beta-ol) in patients with Smith-Lemli-Opitz syndrome.

Cholesta-5,8-dien-3 beta-ol (8-dehydrocholesterol) and cholesta-5,7-dien-3 beta-ol (7-dehydrocholesterol) were isolated from the fecal neutral sterol fraction from homozygotes with Smith-Lemli-Opitz syndrome. The structures of the sterols were conclusively established from their mass spectra and 1H and 13C nuclear magnetic resonance spectra. It is probable that 8-dehydrocholesterol arises from 7-dehydrocholesterol and is not a direct precursor of cholesterol.

Abnormalities, Multiple↗
PubMed1989

Pelizaeus-Merzbacher disease: an X-linked neurologic disorder of myelin metabolism with a novel mutation in the gene encoding proteolipid protein.

The nosology of the inborn errors of myelin metabolism has been stymied by the lack of molecular genetic analysis. Historically, Pelizaeus-Merzbacher disease has encompassed a host of neurologic disorders that present with a deficit of myelin, the membrane elaborated by glial cells that encircles and successively enwraps axons. We describe here a Pelizaeus-Merzbacher pedigree of the classical type, with X-linked inheritance, a typical clinical progression, and a pathologic loss of myelinating cells and myelin in the central nervous system. To discriminate variants of Pelizaeus-Merzbacher disease, a set of oligonucleotide primers was constructed to polymerase-chain-reaction (PCR) amplify and sequence the gene encoding proteolipid protein (PLP), a structural protein that comprises half of the protein of the myelin sheath. The PLP gene in one of two affected males and the carrier mother of this family exhibited a single base difference in the more than 2 kb of the PLP gene sequenced, a C----T transition that would create a serine substitution for proline at the carboxy end of the protein. Our results delineate the clinical features of Pelizaeus-Merzbacher disease, define the possible molecular pathology of this dysmyelinating disorder, and address the molecular classification of inborn errors of myelin metabolism. Patients with the classical form (type I) and the more severely affected, connatal variant of Pelizaeus-Merzbacher disease (type II) would be predicted to display mutation at the PLP locus. The other variants (types III-VI), which have sometimes been categorized as Pelizaeus-Merzbacher disease, may represent mutations in genes encoding other structural myelin proteins or proteins critical to myelination.

Amino Acid Sequence↗
PubMed1988

Counseling needs and attitudes toward prenatal diagnosis and abortion in fragile-X families.

The genetic counseling need of 32 women of normal intelligence at-risk for having children with the fragile-X syndrome (FXS) were determined by a questionnaire study which included assessment of their attitudes toward prenatal diagnosis and the option of pregnancy termination. Eighteen (56%) of the women had one or more children with the FXS and 14 (44%) had no affected children. Twenty-six (81%) of the subjects stated that they would choose to have prenatal diagnosis and 9 (28%) indicated they would terminate an affected pregnancy. There was no significant difference between women who had affected children and those who did not have affected children, nor between Catholics and non-Catholics regarding acceptance of prenatal diagnosis. Catholic women were less likely to consider pregnancy termination than non-Catholics, but the majority of subjects (56%) were unsure what they would do if a fetus they were carrying was found to be affected. Issues the subjects considered most important for discussion with a genetic counselor included: 1) availability of treatment, 2) risk for having an affected grand child, 3) expectations for future functioning of affected children, and 4) availability of prenatal diagnosis.

Abortion, Induced↗
PubMed1988

Lethal osteogenesis imperfecta associated with 46,XY,inv(7)(p13q22) karyotype.

An infant who died of complications of osteogenesis imperfecta (OI) at 22 days of age had a 46,XY,inv(7)(p13q22) karyotype. His mother carried the same inversion. One breakpoint of the inversion was within the region of the gene for alpha 2(I) procollagen. The product of this gene is a component of type I collagen, the principal collagen synthesised by osteoblasts. Karyotypic abnormalities involving type I collagen gene sites have not previously been reported in association with OI.

Chromosome Aberrations↗
PubMed1987

Genetic principles.

The author discusses the basic principles of genetics, including the classification of genetic disorders and a consideration of the rules and mechanisms of inheritance. The most common pitfalls in clinical genetic diagnosis are described, with emphasis on the problem of the negative or misleading family history.

Adult↗
PubMed1986

Midtrimester diagnosis of severe deforming osteogenesis imperfecta with autosomal dominant inheritance.

Sonographic examination of a fetus whose father had severe deforming osteogenesis imperfecta (OI) was performed. The father had multiple congenital rib and extremity fractures. Subsequent fracture and deformity had suggested an autosomal recessive OI syndrome. However, fetal sonography at 18 weeks gestational age showed foreshortening of long bones in both legs and a reduced thoracic circumference, recapitulating, in part, the father's phenotype. This third reported case of early fetal diagnosis of autosomal dominant OI suggests that the fetal sonographic phenotype reflects that of the affected parent. Implications of this case for the application of fetal sonography in dominant OI syndromes are discussed.

Adult↗
PubMed1985

Frequency of fragile X chromosome in normal females.

Because of the ambiguities in diagnosing carriers of the fragile X syndrome, we studied thirty-six normal females to determine whether the fragile site at Xq27 can be seen in noncarrier females and at what frequency. A fragile site at Xq27 was identified in one out of thirty-six females, occurring at a frequency of 0.5% in her peripheral lymphocytes. We conclude that the fragile Xq27 site occurs only rarely in noncarrier females and that each laboratory should determine its own baseline frequencies of fragile X in order to most accurately distinguish between normal and carrier women.

Adult↗
PubMed1977

Reproduction in a woman with low percentage t(21q21q) mosaicism.

The birth of a child is described with Down syndrome followed by the conception of a fetus bearing the t(21q21q) chromosome in 100% of their cells in a women mosiac for the translocation in less than 10% of 2 of her examined tissues and in none of the cells in her peripheral blood. Various hypotheses for explaining the above findings are discussed. The importance of examining as many parental tissues as possible for the detection of low percentage mosiacism is stressed.

Adult↗
PubMed1977

Partial trisomy 8 (trisomy 8q2106 leads to 8qter).

A case of trisomy for part of the long arm of chromosome 8, confirmed by G-banding analysis, in a white male infant is described. The mother carried a reciprocal translocation between chromosome 8 and chromosome 13 (46,XX,t(8;13),(q21:q34). The patient had inherited the translocated chromosome 13 and was thus trisomic for the distal half of the long arm of chromosome 8. He had many of the clinical features of the full trisomy 8 syndrome. As compared with previously reported cases with trisomy of the distal end of chromosome 8, he was more dysmorphic and showed greater developmental retardation.

Abnormalities, Multiple↗
PubMedDate not supplied

Fryns syndrome: a new definition.

Fryns syndrome is a lethal, autosomal recessive syndrome of multiple congenital anomalies described by Fitch et al. in 1978 and Fryns et al. in 1979. As originally described, the major diagnostic criteria included abnormal facies; small thorax with widely spaced, hypoplastic nipples; distal limb and nail hypoplasia; and diaphragmatic hernia with pulmonary hypoplasia. Malformations involving other systems occurred irregularly in published reports. We reviewed 41 published cases of Fryns syndrome and added 4 cases of our own. The major diagnostic criteria described by Fryns were consistent in all cases with the exception of two criteria. Narrow thorax with hypoplastic nipples and gastrointestinal anomalies were present in less than 50% of the cases. Although for 16 of the 41 published cases there was no information on central nervous system findings, 21 of the 29 remaining cases (72%) had CNS malformations. These lesions were absence of corpus callosum, arhinencephaly, and heterotopia of cerebral and cerebellar tissue. Similarly, for 12 of the 41 published cases there was no information on cardiovascular findings but 29 of the 33 remaining cases (88%) had congenital heart disease. These lesions were ventricular septal defects, arterial septal defects, and persistent left superior vena cava. We conclude that central nervous system anomalies and congenital heart disease should be added to the major diagnostic criteria of Fryns syndrome.

Abnormalities, Multiple↗