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Biomedical subjects

R A Pfeiffer

Publications and source records attributed to R A Pfeiffer.

At least 73 records · Page 4Linked to original sources
PubMed1992

A familial mutation in the testis-determining gene SRY shared by both sexes.

A familial mutation in SRY, the gene coding for the testis-determining factor TDF, was identified in an XY female with gonadal dysgenesis, her father, her two brothers and her uncle. The mutation consists of a T to C transition in the region of the SRY gene coding for a protein motif known as the high mobility group (HMG) box, a protein domain known to confer DNA-binding specificity on the SRY protein. This point mutation results in the substitution, at amino acid position 109, of a serine residue for phenylalanine, a conserved aromatic residue in almost all HMG box motifs known. This F109S mutation was not found in 176 male controls. When recombinant wildtype SRY and SRYF109S mutant protein were tested in vitro for binding to the target site AAC AAAG, no differences in DNA-binding activity were observed. These results imply that the F109S mutation either is a rare neutral sequence variant, or produces an SRY protein with slightly altered in vivo activity, the resulting sex phenotype depending on the genetic background or environmental factors.

Amino Acid Sequence↗
PubMed1992

An autosomal recessive variant of spondylo-epiphyseal dysplasia in three sibs.

A report of one male and two female sibs with an unusual form of spondylo-epiphyseal dysplasia (SED) manifesting in late childhood. The anomalies are pronounced at the femoral head. There is platyspondyly with biconcave deformation and irregular vertebral end-plates. As the parents are healthy autosomal recessive inheritance is likely.

Adolescent↗
PubMed1992

The gene for X-linked hydrocephalus maps to Xq28, distal to DXS52.

We report the study of five independent X-linked hydrocephalus (HSAS1) families with polymorphic DNA markers of the Xq28 region. A total of 58 individuals, including 7 living affected males and 22 obligate carriers, have been studied. Maximum lod score was 7.21 at theta = 2.40% for DXS52 (St14-1). A single recombination event was observed between this marker and the HSAS1 locus. Other markers studied were DXS296 (Z = 2.02 at theta = 2.5%), DXS304 (Z = 4.37 at theta = 7.8%), DXS74 (Z = 3.50 at theta = 0%), DXS15 (Z = 1.96 at theta = 5.7%), DXS134 (Z = 3.31 at theta = 0%), and F8C (Z = 5.79 at theta = 0%). These data confirm the localization of the HSAS1 gene to Xq28 and provide evidence for genetic homogeneity of this syndrome. In addition, examination of two obligate recombinant meioses along with multipoint linkage analysis supports the distal localization of the HSAS1 locus with respect to the DXS52 cluster. These observations are of potential interest for future studies aimed at HSAS1 gene characterization.

Chromosome Mapping↗
PubMed1992

A study of ten small supernumerary (marker) chromosomes identified by fluorescence in situ hybridization (FISH).

In seven cases additional minute chromosomes studied by FISH were identified as no. 3, 11, 15, 18, 21 and X. Findings were unexpected except for partial trisomy 21 in an adolescent with minor features of Down's syndrome. Moreover, an i(18p) in a mentally retarded dysmorphic child and an idic(15) in a child with Fallot tetralogy was confirmed. In a child with r(21), a supernumerary marker was shown to be derived from no. 21, while in the mother an additional marker idic(22) was noted.

Amniocentesis↗
PubMed1992

Typical and partial cat eye syndrome: identification of the marker chromosome by FISH.

Three children are reported with typical cat eye syndrome (CES) and three more children with partial CES because of absence of coloboma, in which the supernumerary marker chromosome was studied by FISH. Using a genomic library, and also a centromeric and particularly a cosmid probe of 22q11, partial tetrasomy was shown in all cases.

Anus, Imperforate↗
PubMed1992

Acrocallosal syndrome in a child with de novo inverted tandem duplication of 12p11.2-p13.3.

Report on the child of normal unrelated parents presenting the typical features of acrocallosal syndrome (craniofacial dysmorphy, mental deficiency, convulsive disorder, agenesis of corpus callosum, preaxial polydactyly "hallux duplex" of both feet, and in addition diabetes insipidus) in which a mirror duplication of nearly the entire short arm of chromosome 12 was discovered. Since the symptomatology of trisomy and tetrasomy 12p shows some overlap with acrocallosal syndrome a common origin of the monogenic disorder and the chromosomal phenotypes is discussed.

Abnormalities, Multiple↗
PubMed1991

[Autosome dominant vitreoretinal dystrophy with skeletal dysplasia in one generation].

We report on ten patients of four generations with autosomal dominant vitreoretinal dystrophy with different manifestation. The ophthalmological findings are retinal detachment, retinal holes, retinoschisis, lattice and snowflake degeneration, vitreoretinal adhesions, chorioretinal atrophy and peripheral pigment epithelial changes. Two sisters show growth retardation with skeletal anomalies most likely brachyolmia.

Amblyopia↗
PubMed1991

Interstitial deletion of 16(q13q22) in a newborn resulting from a paternal insertional translocation.

A dysmorphic newborn showed an interstitial deletion of the long arm of a chromosome 16 due to a balanced paternal insertional translocation 46,XY,ins(14;16)(q23;q13q22). The insertion was confirmed by chromosomal in situ suppression (CISS-) hybridization. Clinical features considered to be typical for a 16q- phenotype are demonstrated in this patient. Similar observations described in the literature are compared and discussed with reference to the phenocritical region.

Chromosome Deletion↗
PubMed1991

Interstitial deletion of chromosome 9q with coexistence of the deleted segment as a ring chromosome. A case report.

In a mentally retarded female an interstitial deletion of a chromosome 9 and an additional ring chromosome was shown, which by positive hybridisation with a no 9 library was considered to be the excised segment. The functional centromere and C and DA/DAPI positive material as well on the ring chromosome are explained by a break within the centromere close to the constitutive heterochromatin and supports the hypothesis of "latent" centromere(s).

Chromosome Deletion↗
PubMed1990

X-linked ocular albinism. Characteristic pattern of affection in female carriers.

The authors report on a family with X-linked ocular albinism. Examined were one of three affected males and eight females. Six women were carriers and showed iris retroillumination and typical abnormalities of the fundus. The patchy or striated hypopigmentation of the retinal pigment epithelium is thought to be due to random inactivation of the paternal or maternal X-chromosome respectively. The pattern of affection however represents a nonrandom embryological developmental pattern of the retinal pigment epithelium.

Adult↗
PubMed1990

Hypomelanosis of Ito (incontinentia pigmenti achromians). Ophthalmological evidence for somatic mosaicism.

The authors report on a ten-year-old boy with hypomelanosis of Ito. He suffered from epileptic seizures and exhibited typical generalized partial skin hypomelanosis in whorl-like and striated pattern following Blaschko's lines. The fundi showed patchy, mottled hypopigmentations becoming increasingly striated in the periphery with a general orientation to the optic nerve head. This pattern of affection reminds of the retinal findings in carrier women for X-linked ocular albinism. Magnetic resonance imaging revealed multiple small areas of increased relaxation time scattered in the white matter of the brain, which are interpreted as porencephalic cysts. These clinical findings suggest somatic cell mosaicism even though the cytogenetic study was not conclusive.

Brain Diseases↗