Extensive mongolian spots in an infant with Hurler syndrome.
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Coloring Agents↗
Biomedical subjects
B D Hall
Publications and source records attributed to B D Hall.
Costello syndrome: phenotype, natural history, differential diagnosis, and possible cause.
We describe 8 patients affected with Costello syndrome including an affected sib pair and review the literature on 29 previously reported cases. We emphasize an association with advanced parental age, which is consistent with autosomal dominant inheritance with germline mosaicism. The pathogenesis appears to involve metabolic dysfunction, with growth disturbance, storage disorder appearance, acanthosis nigricans, hypertrophic cardiomyopathy, and occasional abnormalities of glucose metabolism. Although the cause is currently unknown, Costello syndrome is interesting because of a potential genetic-metabolic etiology.
Acanthosis Nigricans↗
Usefulness of RNA polymerase II coding sequences for estimation of green plant phylogeny.
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Amino Acid Sequence↗
CHARGE association: an update and review for the primary pediatrician.
CHARGE association is a nonrandom pattern of congenital anomalies that occurs together more frequently than one would expect on the basis of chance. This common multiple anomaly condition has an estimated prevalence of 1:10,000. The number of children diagnosed with CHARGE association is increasing, owing presumably to greater awareness of this condition and advances in the care of complex, chronically ill children, resulting in improved survival and outcome. This review of CHARGE association presents diagnostic criteria that may define a concise, recognizable syndrome with a single pathogenetic basis. This review also summarizes our current understanding of the management for this complex and chronic multiple congenital anomaly condition and discusses the pathogenetic basis for this condition.
Abnormalities, Multiple↗
Neurosonographic diagnosis of thalamic/basal ganglia vasculopathy in trisomy 13--an important diagnostic aid.
We performed a retrospective review of all the infants diagnosed with trisomy 13 in our institution from 1982 to 1995 and evaluated the neurosonographic findings along with their clinical information and cytogenetic analysis. Nine babies were admitted with trisomy 13. Sonography of the head was performed on 4 patients, and demonstrated in all of them a linear, branching, echogenic pattern in the thalamus/basal ganglia. Doppler evaluation of the thalamus/basal ganglia was performed in 3 of the 4 cases and confirmed these linear echogenicities to be of vascular origin. This is the first study to evaluated the occurrence of this finding in a specific syndrome, namely trisomy 13.
Basal Ganglia↗
Hiatus/paraesophageal hernias in neonatal Marfan syndrome.
We report on an infant with neonatal Marfan syndrome (NMS) and hiatus/paraesophageal hernia who presented to a university hospital with an unusual early complication of this connective tissue disorder. An abnormal course of the nasogastric tube was noted on the first day of life by a radiograph of the chest and abdomen performed for bloody gastric drainage. The question of esophageal perforation was raised. Subsequent contrast study demonstrated a large hiatus/paraesophageal hernia with pronounced gastroesophageal reflux (GER). A part of the hernia was positioned posterior and to the right of the gastroesophageal junction (GEJ), presumably the location of the nasogastric tube as noted on the initial films. Although characterized by cardiac/aortic abnormalities, NMS can be a difficult diagnosis and should be considered in any infant with hiatus/ paraesophageal hernia with or without GER.
Gastroesophageal Reflux↗
Substrate specificity of the RNase activity of yeast RNA polymerase III.
Using yeast RNA polymerase III ternary complexes stalled at various positions on the template, we have analyzed the cleavage products that are retained and released by the transcription complexes. The retained 5' products result from cleavage at uridine residues during retraction, whereas the yield of mononucleotides and dinucleotides released indicates that multiple cuts occur near the 3' end. Comparison of the cleavage patterns of uridine-containing and 5-bromouridine-containing transcripts suggests that RNA within an RNA-DNA hybrid duplex is the substrate for the 3'-5' exonuclease. During transcription of the SUP4 tRNATyr gene, RNA polymerase III produces not only full-length pre-tRNATyr but also short oligonucleotides, indicating that exonuclease digestion and transcription are concurrent processes. To explore the possibility that these oligonucleotides are released by the action of the RNA polymerase III nuclease at previously observed uridine-rich pause sites, we tested modified templates lacking the arrest sites present in the SUP4 tRNATyr gene. Comparative studies of cleavage during transcription for these templates show a direct correlation between the number of natural pause sites and the yield of 3' products made. At the natural arrest sites and the terminator, RNA polymerase III carries out multiple cleavage resynthesis steps, producing short oligoribonucleotides with uridine residues at the 3' terminus.
Base Sequence↗
Macrocephaly-cutis marmorata telangiectatica congenita: a distinct disorder with developmental delay and connective tissue abnormalities.
We describe 13 unrelated children with abnormalities of somatic growth, face, brain, and connective tissue including vasculature. Although the condition in these children falls under the general group of disorders known as cutis marmorata telangiectatica congenita (CMTC), the constellation of abnormalities appears to constitute a distinct and easily recognizable phenotype within this general group. In contrast to most children reported with CMTC, children in this subgroup have a high risk for neurologic abnormalities, including developmental delay, mental retardation, megalencephaly, and hydrocephalus. Early recognition of this condition is important for appropriate surveillance for known complications and parental counseling.
Abnormalities, Multiple↗
The origin of red algae: implications for plastid evolution.
The origin of the red algae has remained an enigma. Historically the Rhodophyta were classified first as plants and later as the most ancient eukaryotic organisms. Recent molecular studies have indicated similarities between red and green plastids, which suggest that there was a single endosymbiotic origin for these organelles in a common ancestor of the rhodophytes and green plants. Previous efforts to confirm or reject this effort by analyses of nuclear DNA have been inconclusive; thus, additional molecular markers are needed to establish the relationship between the host cell lineages, independent of the evolutionary history of their plastids. To furnish such a data set we have sequenced the largest subunit of RNA polymerase II from two red algae, a green alga and a relatively derived amoeboid protist. Phylogenetic analyses provide strong statistical support for an early evolutionary emergence of the Rhodophyta that preceded the origin of the line that led to plants, animals, and fungi. These data, which are congruent with results from extensive analyses of nuclear rDNA, argue for a reexamination of current models of plastid evolution.
Acanthamoeba↗
Syndrome of microcephaly, facial and hand abnormalities, tracheoesophageal fistula, duodenal atresia, and developmental delay.
We report on six new families (12 new patients) with the syndrome of microcephaly, facial and hand abnormalities, tracheoesophageal fistula, duodenal atresia, and developmental delay. The most common findings were hand abnormalities, microcephaly, short and/or narrow palpebral fissures, broad nasal bridge, anteverted nostrils, ear abnormalities, and micrognathia. Inheritance is autosomal dominant. There is a significant amount of intrafamilial variability especially as it relates to the gastrointestinal findings. Although the first patients reported, who were very young, did not exhibit any developmental delay, they subsequently did develop learning problems, and 87% of our 12 patients had mental retardation or learning difficulties.
Abnormalities, Multiple↗
Humero-spinal dysostosis: report of the fourth case with emphasis on generalized skeletal involvement, abnormal craniofacial features, and mitral valve thickening.
The fourth reported case of humero-spinal dysostosis is notable in that (a) it confirms the unique combination of bifid distal humeri and coronal clefts, (b) involves a third unique feature as being mitral valve thickening. (c) suggests a more generalized involvement of bone in the form of a dysplasia, and (d) raises the possibility of repetitive craniofacial features.
Abnormalities, Multiple↗
Bioaccumulation of mercury in the aquatic food chain in newly flooded areas.
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Animals↗
Diastrophic dysplasia: extreme variability within a sibship.
Three sibs were eventually diagnosed as having diastrophic dysplasia. The firstborn, a male, lacked many of the clinical manifestations and radiological abnormalities of the hands, such that the diagnosis of diastrophic dysplasia could not be made. Subsequently, his twin sisters were born with more severe skeletal involvement, but not many additional clinical findings, until one of his sisters (patient 2) developed a left ear cyst at age 2 months. Some cases of diastrophic dysplasia may be mild enough not to allow for a secure diagnosis, particularly in a neonate or infant occurring as the first affected person in the family.
Abnormalities, Multiple↗
Prenatal ultrasound findings in hydrolethalus: continuing difficulties in diagnosis.
We present the prenatal ultrasound findings in a case of hydrolethalus. This case illustrates ongoing problems in differentiating hydrolethalus, both pre- and postnatally, from other midline malformation syndromes including Pallister-Hall, Smith-Lemli-Opitz, pseudo-trisomy 13, oral facial-digital syndrome, and Meckel syndrome. Hydrolethalus can also be difficult to distinguish from certain skeletal dysplasias such as the short rib-polydactyly syndromes and campomelic dysplasia. Tests which can aid in diagnosis are presented.
Adult↗
Photographic analysis: a quantitative approach to the evaluation of dysmorphology.
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Ethnicity↗
Fibroblast growth factor receptor 2 mutations in Beare-Stevenson cutis gyrata syndrome.
Beare-Stevenson cutis gyrata syndrome (MIM 123790) is an autosomal dominant condition characterized by the furrowed skin disorder of cutis gyrata, acanthosis nigricans, craniosynostosis, craniofacial dysmorphism, digital anomalies, umbilical and anogenital abnormalities and early death. Many of these features are characteristic of some of the autosomal dominant craniosynostotic syndromes. Mutations in Crouzon, Jackson-Weiss, Pfeiffer and Apert syndromes have been reported in the FGFR2 extracellular domain. In Crouzon syndrome patients with acanthosis nigricans, a recurrent mutation occurs in the transmembrane domain of FGFR3. We now describe the detection of FGFR2 mutations in the Beare-Stevenson cutis gyrata syndrome. In three sporatic cases, a novel missense mutation was found causing an amino acid to be replaced by a cysteine; two had the identical Ty375Cys mutation in the transmembrane domain and one had a Ser372Cys mutation in the carboxyl-terminal end of the linker region between the immunoglobulin III-like (Iglll) and transmembrane domains. In two patients, neither of these mutations were found suggesting further genetic heterogeneity.
Abnormalities, Multiple↗
Purines are required at the 5' ends of newly initiated RNAs for optimal RNA polymerase III gene expression.
We have made specific alterations in the CAACAA element at the transcription start site of a Saccharomyces cerevisiae suppressor tRNA gene. The mutant genes were tested for their ability to suppress the ochre nonsense alleles ade2-1, lys4-1, and met4-1. Many of the mutants showed either no phenotypic change or a weak loss of suppression relative to that of SUP4-o. A 2-bp change, CTCCAA, which alters bases encoding the +1 and +2 nucleotides of pre-tRNA Tyr, had a strong deleterious effect in vivo, as did the more extensive change CTCCTC. In contrast, mutant genes bearing each of the possible single changes at nucleotide +1 retained normal suppression levels. The transcription start point could be shifted in a limited fashion in response to the specific sequences encountered by RNA polymerase III at the start site. ATP was preferentially utilized as the 5' nucleotide in the growing RNA chain, while with start site sequences that precluded utilization of a purine, CTP was greatly preferred to UTP as the +1 nucleotide. Short oligopyrimidine RNAs formed on the CTCCTC allele could be repositioned in the active center of the newly formed ternary complex. Early postinitiation complexes containing short nascent RNAs formed on the CTCCTC mutant were more sensitive to the effects of heparin and produced more abortive transcripts than similar complexes formed on SUP4-o. Our results suggest that the purine-rich sequences at the 5' ends of the nascent transcripts of many genes act to stabilize the early ternary complex.
Alleles↗
In vitro analysis of elongation and termination by mutant RNA polymerases with altered termination behavior.
We have studied the in vitro elongation and termination properties of several yeast RNA polymerase III (pol III) mutant enzymes that have altered in vivo termination behavior (S. A. Shaaban, B. M. Krupp, and B. D. Hall, Mol. Cell. Biol. 15:1467-1478, 1995). The pattern of completed-transcript release was also characterized for three of the mutant enzymes. The mutations studied occupy amino acid regions 300 to 325, 455 to 521, and 1061 to 1082 of the RET1 protein (P. James, S. Whelen, and B. D. Hall, J. Biol. Chem. 266:5616-5624, 1991), the second largest subunit of yeast RNA pol III. In general, mutant enzymes which have increased termination require a longer time to traverse a template gene than does wild-type pol III; the converse holds true for most decreased-termination mutants. One increased-termination mutant (K310T I324K) was faster and two reduced termination mutants (K512N and T455I E478K) were slower than the wild-type enzyme. In most cases, these changes in overall elongation kinetics can be accounted for by a correspondingly longer or shorter dwell time at pause sites within the SUP4 tRNA(Tyr) gene. Of the three mutants analyzed for RNA release, one (T455I) was similar to the wild type while the two others (T455I E478K and E478K) bound the completed SUP4 pre-tRNA more avidly. The results of this study support the view that termination is a multistep pathway in which several different regions of the RET1 protein are actively involved. Region 300 to 325 likely affects a step involved in RNA release, while the Rif homology region, amino acids 455 to 521, interacts with the nascent RNA 3' end. The dual effects of several mutations on both elongation kinetics and RNA release suggest that the protein motifs affected by them have multiple roles in the steps leading to transcription termination.
Amino Acid Sequence↗