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Biomedical subjects

R A Pagon

Publications and source records attributed to R A Pagon.

At least 19 recordsLinked to original sources
PubMed1992

Preferential mutation of the neurofibromatosis type 1 gene in paternally derived chromosomes.

An interesting feature of neurofibromatosis type 1 (NF1) is its high mutation rate of 1 x 10(-4) per gamete per generation. The molecular basis for frequent NF1 mutation in unknown; the gene is not deletion prone. We have found that in all ten families examined, the apparent new NF1 mutation occurred on the paternally-derived chromosome. The probability of observing this result by chance is less than 0.001 assuming an equal frequency of mutation of paternal and maternal NF1 genes. We hypothesize a role for genomic imprinting that may either enhance mutation of the paternal NF1 gene or confer protection from mutation to the maternal NF1 gene.

Chromosomes, Human↗
PubMed1992

Deletion mapping of H-Y antigen to the long arm of the human Y chromosome.

A gene encoding or controlling the expression of the H-Y transplantation antigen was previously mapped to the human Y chromosome. We now report the sublocalization of this gene on the long arm of the human Y chromosome. Eight patients with Y-chromosomal abnormalities were examined with a series of existing and new DNA markers for the Y chromosome. The resulting deletion map was correlated with H-Y antigen expression. We conclude that the H-Y antigen gene maps to a portion of deletion interval 6 that is identified by specific DNA markers.

Adolescent↗
PubMed1992

Causal heterogeneity in isolated lissencephaly.

We report clinical, cytogenetic, and molecular studies in 65 patients with isolated lissencephaly sequence (ILS). All had type I lissencephaly of varying severity and a grossly normal cerebellum. Some had additional brain abnormalities. Facial appearance was essentially normal. All had severe to profound mental retardation, seizures, hypotonia that evolved into spasticity, and feeding difficulties. Clinical and laboratory studies demonstrated etiologic heterogeneity. Molecular studies detected microdeletions in chromosome band 17p13.3 in six of 44 patients tested, confirming that deletion of all or part of this "critical region" is the cause of ILS in some cases. There were slightly larger deletions in the same region in a majority of patients with Miller-Dieker syndrome. One patient had an apparently balanced, de novo reciprocal translocation with breakpoints at Xq22 and 2p25. Four sibs from two families had a new, autosomal recessive syndrome of ILS with neonatal death. Other causes supported by clinical observations include autosomal recessive inheritance, intrauterine infection, and intrauterine perfusion failure. Those ILS probands in whom no etiology could be established had 41 sibs of whom three were affected, giving an empiric recurrence risk of 7%.

Brain↗
PubMed1992

Autosomal dominant transmission of acrodysostosis.

A mother and daughter with acrodysostosis are described. This documented parent-to-child transmission supports the hypothesis of autosomal dominant inheritance of acrodysostosis. The daughter exhibited many features of acrodysostosis by two months of age, demonstrating that acrodysostosis may be diagnosed in infancy.

Adult↗
PubMed1991

Twin fetuses with abnormalities that overlap with three midline malformation complexes.

Twin fetuses aborted at an estimated gestational age of 145 days were concordant for oral, facial, skeletal, and central nervous system malformations. The twins were discordant for other anomalies including cardiac defects, polydactyly, and malrotated short bowel. The combination of malformations observed overlaps with that of the oral-facial-digital syndrome, hydrolethalus syndrome, and Pallister-Hall syndrome. The problem of phenotypic overlap between these syndromes is discussed.

Abnormalities, Multiple↗
PubMed1991

Nasal dermoid sinus cysts: association with intracranial extension and multiple malformations.

Nasal dermoid and sinus cysts (NDSC) are uncommon congenital anomalies that may have intracranial extension and can be associated with other anomalies. We identified 22 patients in a retrospective review of cases diagnosed with NDSC at our institution over the past 10 years. Nine (41 percent) had associated anomalies and ten (45 percent) had intracranial extension of the sinus. In half of the patients with intracranial extension, the sinus transversed either the cribriform plate or foramen cecum and attached to the dura; in the other half, the sinus extended to cysts within the falx or other brain structures. Of the patients with multiple anomalies, six (67 percent) had intracranial extension. Presurgical complications occurred in a total of eight patients (36 percent): two had meningitis, two had osteomyelitis, four had periorbital-nasal cellulitis, three had nasal abscess, and four had nose anomalies requiring rhinoplasty.

Abnormalities, Multiple↗
PubMed1991

X-linked sideroblastic anemia and ataxia: linkage to phosphoglycerate kinase at Xq13.

Molecular linkage analysis was performed on a kindred with X-linked sideroblastic anemia and ataxia. Two-point analysis with a DNA probe for phosphoglycerate kinase (PGK1), which maps to Xq13, suggested linkage to the disorder by a lod score of at least 2.60 at a recombination fraction of zero. The disease in this kindred appears to be clinically and genetically distinct from that in previously reported families with X-linked hereditary ataxia or spastic paraparesis. No mapping data are available for inherited X-linked sideroblastic anemia without neurologic abnormalities. However, structural alterations of band Xq13 may be involved in the development of idiopathic acquired sideroblastic anemia. No alterations in the restriction patterns of two X-linked genes involved in erythrocyte formation-i.e., a DNA-binding protein (GF-1) and 5-aminolevulinate synthase (ALAS)-were detected in DNA from affected males, arguing against a large deletion in either of these candidate genes.

Anemia, Sideroblastic↗
PubMed1990

Partial deletion of the long arm of chromosome 11 [del(11)(q23.3----qter)] with abnormal white matter.

A patient with partial deletion of the long arm of chromosome 11[del(11)(q23.3----qter)] had macrocephalic trigonocephaly, growth and mental retardation, congenital heart defect, and characteristic facial appearance familiar to that of 33 other reported patients with this deletion. Computed tomography (CT) and magnetic resonance imaging of this infant's brain demonstrated abnormality of the supratentorial white matter. This may represent either deficiency or delay in myelination or possibly a demyelination process. No abnormalities in white matter were described in seven of 33 previously reported patients whose brains were examined by ultrasound, CT, or autopsy.

Abnormalities, Multiple↗
PubMed1990

Incidence of tuberous sclerosis in patients with cardiac rhabdomyoma.

Cardiac rhabdomyoma, a rare benign tumor often detected in infancy, is frequently associated with tuberous sclerosis. This association is commonly stated to occur in 50% of all cases of cardiac rhabdomyoma. Recently at our institution, the prenatal detection of a cardiac rhabdomyoma in a fetus at no known risk for tuberous sclerosis emphasized the need to determine the frequency of association in order to provide accurate diagnosis and counseling in such situations. After a review of reported cases and review of patients from our institution diagnosed to have cardiac rhabdomyoma, we estimate that 51-86% of cardiac rhabdomyomas are associated with tuberous sclerosis. We present the results of our literature and case review.

Female↗
PubMed1990

Geleophysic dysplasia: a storage disorder affecting the skin, bone, liver, heart, and trachea.

Geleophysic dysplasia is characterized by typical facies ("happy natured"), small hands and feet, short stature, hepatomegaly, and progressive cardiac disease. We describe five patients (two of whom are siblings) with this disorder and document its variable expressivity. The facies were strikingly similar with small nose, anteverted nostrils, broad nasal bridge, and long thin upper lip with flat and long philtrum. Behavior, development, and intelligence were normal. Growth delay was noticed during infancy, and the two patients who completed normal puberty had marked short stature (140 and 150 cm), with relatively lean body habitus. The hands and feet were small, with short, plump tubular bones and broad proximal phalanges, associated with marked limitation in motion of fingers and wrists. The liver was enlarged after the age of 3 years. Two patients had mild mitral and tricuspid valve stenosis and one had severe aortic stenosis. The most severely affected child died at 3 1/2 years of age of airway obstruction as a result of progressive tracheal narrowing. Lysosomal storage vacuoles were found in skin epithelial cells from three patients whose skin was examined, and in the tracheal mucosa, liver, cartilage and macrophages of the child who died. The basic defect of this autosomal recessive lysosomal storage disease remains to be determined.

Adolescent↗
PubMed1990

Pigmentary abnormalities and mosaicism for chromosomal aberration: association with clinical features similar to hypomelanosis of Ito.

Thirteen patients with hypopigmentation of the skin characteristic of hypomelanosis of Ito, and with developmental disabilities or structural malformations, or both, were examined at our center. Eight were found to have abnormal karyotypes in lymphocytes, fibroblasts, or both. No single clinical feature was predictive of chromosome imbalance in this group of patients. Cytogenetic findings included a balanced de novo X-autosome translocation; ring 10; 45,X/46,X,+ring; mosaic del 13q11 (fibroblasts); mosaic triploidy (fibroblasts); mosaic tetrasomy 12p (fibroblasts); mosaic apparently balanced 15;22 translocation (peripheral blood); and mosaic trisomy 18 (peripheral blood). Hypomelanosis of Ito is characterized by swirly hypopigmentation or depigmentation of the skin with or without other malformations. Autosomal dominant, autosomal recessive, and X-linked dominant inheritance have been suggested but not confirmed. Chromosomal aneuploidy has also been reported. We believe that hypomelanosis of Ito is an etiologically heterogeneous physical finding, and recommend karyotyping of multiple tissues of all patients with abnormal cutaneous pigmentation associated with developmental delay or structural malformations.

Adolescent↗
PubMed1990

Rhizomelic chondrodysplasia punctata and survival beyond one year: a review of the literature and five case reports.

Rhizomelic chondrodysplasia punctata (RCDP), a peroxisomal disorder, is considered to be a lethal neonatal autosomal recessive chondrodysplasia. We report five patients, three of whom survived beyond 1 year, and we summarize the findings in 21 patients from a literature review who survived beyond 1 year. In those patients that survive, there is a high association of spasticity, psychomotor retardation, growth failure, seizures, thermoregulatory instability, feeding difficulty, and recurrent otitis media and pneumonia. Three of our five patients had no radiographic evidence of vertebral body clefts, a finding which has previously been considered invariable in RCDP. Three of our patients had distinctive facies that differ from the classic Conradi-Hunermann facies.

Bone and Bones↗
PubMed1990

Impaired skin fibroblast carnitine uptake in primary systemic carnitine deficiency manifested by childhood carnitine-responsive cardiomyopathy.

Evidence is emerging that primary systemic carnitine deficiency, a potentially lethal but eminently treatable inborn error of fatty acid oxidation, involves a cellular defect in the uptake of carnitine. We present four unrelated children with primary carnitine-responsive cardiomyopathy, weakness (with or without hypoketotic hypoglycemic encephalopathy), low serum and/or tissue carnitine concentrations, and severe renal carnitine leak. Dicarboxylic acids were absent in the urine of three children who were tested, and all four had a rapid and dramatic improvement in cardiac function, strength, and somatic growth after carnitine therapy. We studied carnitine uptake in cultured skin fibroblasts from all four children and seven of the eight healthy nonconsanguinous parents. [3H]L-carnitine uptake was evaluated in vitro under linear time kinetics. Substrate concentrations were varied from 0.1 to 1000 microM. Physiologic uptake was determined at carnitine concentrations between 0.1 and 50 microM. Nonspecific uptake was determined at a concentration of 10 mM. The four patients had negligible uptake throughout the physiologic range, implying a marked deficiency in the specific high-affinity, low-concentration, carrier-mediated uptake mechanism. At a concentration of 5 mumol/L, the mean velocity of uptake in the four patients was 2% of control values. Their parents showed intermediate maximal rates of carnitine uptake ranging from 13 to 44% of control Vmax values, but normal Km values, suggesting that the heterozygotes had a reduced number of normal functioning carnitine transporters. The observed reduction in Vmax values for the parents supports an autosomal recessive inheritance pattern and may be a more sensitive indicator of heterozygosity than serum carnitine concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Transport, Active↗
PubMed1989

Diagnostic criteria for Walker-Warburg syndrome.

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder manifest by characteristic brain and eye malformations. We reviewed data on 21 of our patients and an additional 42 patients from the literature. From this review, we expand the phenotype to include congenital muscular dystrophy (CMD) and cleft lip and/or palate (CLP), and revise the diagnostic criteria. Four abnormalities were present in all patients checked for these anomalies: type II lissencephaly (21/21), cerebellar malformation (20/20), retinal malformation (18/18), and CMD (14/14). We propose that these comprise necessary and sufficient diagnostic criteria for WWS. Two other frequently observed abnormalities, ventricular dilatation with or without hydrocephalus (20/21) and anterior chamber malformation (16/21), are helpful but not necessary diagnostic criteria because they were not constant. All other abnormalities occurred less frequently. Congenital macrocephaly with hydrocephalus (11/19) was more common than congenital microcephaly (3/19). Dandy-Walker malformation (10/19) was sometimes associated with posterior cephalocele (5/21). Additional abnormalities included slit-like ventricles (1/21), microphthalmia (8/21), ocular colobomas (3/15), congenital cataracts (7/20), genital anomalies in males (5/8), and CLP (4/21). Median survival in our series was 9 months. A related autosomal recessive disorder, Fukuyama congenital muscular dystrophy, consists of similar but less severe brain changes and CMD. It differs from WWS because of consistently less frequent and severe cerebellar and retinal abnormalities. We think that WWS is identical to "cerebro-oculo-muscular syndrome" and "muscle, eye, and brain disease."

Brain↗
PubMed1989

Molecular analysis of 46,XY females and regional assignment of a new Y-chromosome-specific probe.

The relationship between Y-chromosome abnormalities and gonadal differentiation was investigated in six phenotypic females with a 46,XY karyotype and one patient with ambiguous genitalia secondary to apparently nonmosaic 46,XY mixed gonadal dysgenesis. No alterations were found in the Y chromosomes of six of these individuals by the use of either cytogenetic or molecular techniques. Cytogenetic analysis with high-resolution G-banding and Q-banding revealed a small deletion in the short arm of the Y chromosome in one female patient with some features of Turner syndrome. Southern hybridization with Y-specific probes showed a loss of DNA within deletion intervals 1, 2, and 3 of the Y chromosome. A new Y-chromosome-specific DNA probe that hybridizes to deletion interval 3 is described.

Abnormalities, Multiple↗
PubMed1988

Visceral myopathy of the gastrointestinal and genitourinary tracts in infants.

We describe 4 infants who had chronic intestinal pseudoobstruction caused by visceral myopathy. Three of the 4 were girls. Two were symptomatic at birth and 2 were symptomatic by 3 wk of age. All had abdominal distention and emaciation, 3 of the 4 had severe obstipation and fecal impactions, and 3 had signs of urologic obstruction. All had gaseous distention of the small bowel and colon, and barium studies showed dilated small bowel and colon, with slow transport through the small intestine. Two of 3 had enlarged stomachs and slowed gastric emptying, and 3 had dilated bladders and ureters. The 1 infant studied by esophageal manometry had absence of esophageal contractions. Despite total parenteral nutrition in 3, all died within 10-18 mo. The pathologic features of visceral myopathy were identified in variable sample sites from the esophagus, stomach, small intestine, colon, bladder, and ureter of the 4 infants. Of 170 family members related to 3 of the infants, there was no consanguinity and no one appeared to be clinically affected. Thus, an infantile form of visceral myopathy exists which, pathologically, is identical to the familial and sporadic forms of visceral myopathy previously identified in adolescents and adults.

Digestive System↗
PubMed1988

Nonfluorescent dicentric Y in males with hypospadias.

We report three boys with severe hypospadias and bilaterally palpable testes with abnormalities of the Y chromosome detected by Q-banding. Severe hypospadias with palpable testes is an unusual presentation for Y chromosome abnormalities. Based on our experience, we recommend that boys with this phenotype undergo complete cytogenetic evaluation, because Y chromosome abnormalities prompt additional management concerns.

Humans↗