Search PubMed⌕ Search

Biomedical subjects

R A Pagon

Publications and source records attributed to R A Pagon.

At least 37 records · Page 2Linked to original sources
PubMed1996

Prevalence of hypopigmented macules in a healthy population.

OBJECTIVE: Although hypopigmented macules are an important manifestation of tuberous sclerosis (TS), the probability of TS in healthy individuals who have hypopigmented macules is unknown. The purpose of this study was to establish the prevalence of hypopigmented macules among a cross section of the general white population. STUDY DESIGN: The skin of 423 white individuals younger than 45 years of age was screened for hypopigmented macules with ambient incandescent and fluorescent light and a Wood lamp. Indirect ophthalmoscopy was performed in patients with unexplained hypopigmentation to screen for retinal manifestations of TS. RESULTS: Twenty individuals (4.7%) had at least one hypopigmented macule. Of these, four had more than one macule. None had more than three. Two (8%) of the 25 hypopigmented macules were identified only with a Wood lamp. Indirect ophthalmoscopy was performed in 13 (65%) of these 20 individuals. None showed the retinal findings of TS. CONCLUSIONS: The prevalence of hypopigmented macules in the general population has been underestimated. The presence of a few hypopigmented macules on the skin of an otherwise healthy individual without a family history of TS need not prompt an evaluation to rule out this disorder.

Adolescent↗
PubMed1996

Marinesco-Sjögren syndrome: clinical and magnetic resonance imaging features in three children.

The authors describe clinical and MRI features of a girl and two boys, aged 9, 17 and 19 years, respectively, with Marinesco-Sjögren syndrome. The clinical findings included the major features of the syndrome, including growth deficiency, ataxia, cataracts, hypogonadism (in two) and seizures (in two). Truncal hypotonia (in three), microcephaly (in two) and leg spasticity (in two) were also present. MRI showed a very small cerebellar vermis in all three patients, various supratentorial abnormalities, an apparently small anterior pituitary gland in two and the absence of a posterior pituitary gland in all three. The MRI features are similar to the few reported pathologic findings for persons with Marinesco-Sjögren syndrome. MRI may be helpful in the early diagnosis of the disorder.

Adolescent↗
PubMed1996

Marinesco-Sjögren syndrome: clinical and magnetic resonance imaging features in three children.

The authors describe clinical and MRI features of a girl and two boys, aged 9, 17 and 19 years, respectively, with Marinesco-Sjögren syndrome. The clinical findings included the major features of the syndrome, including growth deficiency, ataxia, cataracts, hypogonadism (in two) and seizures (in two). Truncal hypotonia (in three), microcephaly (in two) and leg spasticity (in two) were also present. MRI showed a very small cerebellar vermis in all three patients, various supratentorial abnormalities, an apparently small anterior pituitary gland in two and the absence of a posterior pituitary gland in all three. The MRI features are similar to the few reported pathologic findings for persons with Marinesco-Sjögren syndrome. MRI may be helpful in the early diagnosis of the disorder.

Adolescent↗
PubMed1996

Genomic sequence of the DAX1 gene: an orphan nuclear receptor responsible for X-linked adrenal hypoplasia congenita and hypogonadotropic hypogonadism.

The gene responsible for X-linked adrenal hypoplasia congenita, DAX1, encodes a member of the nuclear hormone receptor superfamily. We sequenced 8851 bp that contained the DAX1 genomic region. The DAX gene was composed of two exons and one 3.4-kilobase intron. Putative TATA and GC boxes and a putative steroidogenic factor 1 response element were present in the 5'-flanking region. Two potentially polymorphic short tandem repeats were identified. The first exon encoded two putative novel zinc finger motifs within a putative DNA binding domain and part of the ligand binding domain, and the second exon encoded the remainder of the ligand binding domain. Although the putative DNA binding domain of DAX1 does not contain substantial sequence similarity to other nuclear hormone receptor superfamily members, the putative ligand binding domain had remarkable similarity to other family members. Single-strand conformational polymorphism analysis permitted identification of three new mutations in DAX1. In conclusion, single-strand conformational polymorphism analysis facilitates identification of mutations in the DAX1 gene, and the short tandem repeats may permit linkage analysis in families in which mutations are not yet identified. We speculate that DAX1 may be the most primitive member of the nuclear hormone receptor superfamily identified in mammals.

Adrenal Insufficiency↗
PubMed1994

Okihiro syndrome.

Explore the source record for details and available documents.

Abnormalities, Multiple↗
PubMed1994

The 8993 mtDNA mutation: heteroplasmy and clinical presentation in three families.

The point mutation at bp 8993 of human mtDNA in the ATPase 6 gene is associated with neurogenic weakness, ataxia and retinitis pigmentosa, and with subacute necrotizing encephalomyelopathy (Leigh disease) when present at high copy number. In this study we describe three new multiplex families with the ATPase 8993 mtDNA mutation and demonstrate a correlation between the percentage heteroplasmy of this mutation and the clinical phenotype. By combining this study with previous data we produce a graph of age of onset of symptoms versus percentage heteroplasmy of the mutation. Finally, we determine that ATP synthesis with NAD-linked substrates in cultured lymphoblast mitochondria from three patients with Leigh disease who had a high percentage heteroplasmy was on average 66% of the rate seen in control lymphoblast mitochondria. Similar rates are observed in lymphoblast mitochondria isolated from patients with Leigh disease due to complex I deficiency. This percentage appears to be independent of the rate of electron transport in mitochondria from patient cell lines with the mtDNA 8993 mutation.

Adenosine Triphosphatases↗
PubMed1994

A contiguous gene deletion syndrome at 7q21-q22 and implications for a relationship between isolated ectrodactyly and syndromic ectrodactyly.

Ectrodactyly is a genetically heterogeneous human limb developmental malformation with an autosomal locus at 7q21 designated SHFD1. We report a patient with ectrodactyly and a small interstitial deletion of 7q21, detected by high resolution karyotype, which provides additional evidence for the existence of an ectrodactyly gene in this region and further restricts the size of the critical region containing SHFD1. A review of previously published patients with ectrodactyly and similar deletions suggests a contiguous gene deletion syndrome at 7q21-q22 which consists of ectrodactyly, growth retardation, developmental delay, hypertelorism, ear malformation, components of the Robin sequence, and GU abnormalities. Moreover, the clinical, genetic, and cytogenetic similarities of a number of multiple congenital anomaly syndromes which include ectrodactyly as just one component lead us to propose that a common genetic basis may underlie many of these syndromes. Thus, evaluation for related physical anomalies and high resolution cytogenetic studies are indicated in patients with ectrodactyly.

Abnormalities, Multiple↗
PubMed1994

Phenotypic variability in X-linked ocular albinism: relationship to linkage genotypes.

One hundred nineteen individuals from 11 families with X-linked ocular albinism (OA1) were studied with respect to both their clinical phenotypes and their linkage genotypes. In a four-generation Australian family, two affected males and an obligatory carrier lacked cutaneous melanin macroglobules (MMGs); ocular features were identical to those of Nettleship-Falls OA1. Four other families had more unusual phenotypic features in addition to OA1. All OA1 families were genotyped at DXS16, DXS85, DXS143, STS, and DXS452 and for a CA-repeat polymorphism at the Kallmann syndrome locus (KAL). Separate two-point linkage analyses were performed for the following: group A, six families with biopsy-proved MMGs in at least one affected male; group B, four families whose biopsy status was not known; and group C, OA-9 only (16 samples), the family without MMGs. At the set of loci closest to OA1, there is no clear evidence in our data set for locus heterogeneity between groups A and C or among the four other families with complex phenotypes. Combined multipoint analysis (LINKMAP) in the 11 families and analysis of individual recombination events confirms that the major locus for OA1 resides within the DXS85-DXS143 interval. We suggest that more detailed clinical evaluations of OA1 individuals and families should be performed for future correlation with specific mutations in candidate OA1 genes.

Albinism, Ocular↗
PubMed1994

Fine mapping of the autosomal dominant split hand/split foot locus on chromosome 7, band q21.3-q22.1.

Split hand/split foot (SHFD) is a human developmental defect characterized by missing digits, fusion of remaining digits, and a deep median cleft in the hands and feet. Cytogenetic studies of deletions and translocations associated with this disorder have indicated that an autosomal dominant split hand/split foot locus (gene SHFD1) maps to 7q21-q22. To characterize the SHFD1 locus, somatic cell hybrid lines were constructed from cytogenetically abnormal individuals with SHFD. Molecular analysis resulted in the localization of 93 DNA markers to one of 10 intervals surrounding the SHFD1 locus. The translocation breakpoints in four SHFD patients were encompassed by the smallest region of overlap among the SHfD-associated deletions. The order of DNA markers in the SHFD1 critical region has been defined as PON-D7S812-SHFD1-D7S811-ASNS. One DNA marker, D7S811, detected altered restriction enzyme fragments in three patients with translocations when examined by pulsed-field gel electrophoresis (PFGE). These data map SHFD1, a gene that is crucial for human limb differentiation, to a small interval in the q21.3-q22.1 region of human chromosome 7.

Adult↗
PubMed1993

Mosaic isochromosome 8p.

Findings in a patient with mosaic isochromosome 8p are compared with those of previously reported cases. There were no distinguishing findings on physical examination; all had cognitive delays, especially in speech and language development.

Abnormalities, Multiple↗
PubMed1993

Mapping of the distal boundary of the X-inactivation center in a rearranged X chromosome from a female expressing XIST.

A female patient with primary amenorrhea, immature secondary sexual characteristics, and tall stature was found to have a normal X chromosome and a rearranged X [rea(X)] chromosome that resembled an 'isochromosome' Xp, but retained the proximal portion of Xq. The rea(X) was interpreted as rec(X)dup p,inv(X)(p11.4q13). Replication studies demonstrated that the rea(X) was always the late-replicating and, therefore, presumably inactive X chromosome, which must contain the X-inactivation center. Consistent with this interpretation, fluorescence in situ hybridization demonstrated that the rea(X) retained the XIST gene, and reverse transcription polymerase chain reaction analysis showed that XIST was expressed in the patient's cells. By fluorescence in situ hybridization with previously mapped probes, the breakpoint of the rea(X) was located within an approximately 500-kb region located approximately 200 to 700 kb distal to the XIST locus. This is the closest breakpoint distal to XIST in an inactivated X chromosome and, therefore, defines a new distal boundary for the X-inactivation center in humans.

Adolescent↗
PubMed1993

Phenotypic correlations of ocular coloboma without known cause.

Ocular coloboma can occur as an autosomal dominant condition or as part of a known syndrome or chromosomal abnormality. We have designated those patients with ocular coloboma who do not fit into any of these three groups as having coloboma without known cause. We completed a retrospective review of 58 patients from our clinics with coloboma without known cause to determine the frequency of other co-existing congenital malformations and mental retardation. Mental retardation was present in 14 of the 42 patients (33%) who were more than 1 year of age. However, only 14% of the children who had no other malformations had mental retardation, whereas 57% of those with other malformations were mentally retarded. We found that the severity of the colobomatous malformation did not correlate with intellect.

Adolescent↗
PubMed1993

Familial hydrocephalus with a low-insertion umbilicus.

Two brothers, age 16 months and 3 years, had a seemingly unique combination of hydrocephalus of the lateral ventricles and a low-insertion umbilicus. Both had similar mildly unusual facies and inguinal hernias; one had unilateral cryptorchidism. The older brother had tetralogy of Fallot, and the younger had mildly enlarged, echogenic kidneys with vesicoureteral reflux. Neither boy had adducted thumbs, pyramidal tract signs, or significant developmental delay. A review of the literature on familial hydrocephalus found no similar cases. A low-set umbilicus is not a frequently noted anomaly; its embryology and associated syndromes are discussed. The association of hydrocephalus and a low-set umbilicus appears to be the manifestation of a monogenic disorder in this family, and could be inherited in either an autosomal recessive or X-linked recessive manner.

Child, Preschool↗
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↗