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Biomedical subjects

W B Dobyns

Publications and source records attributed to W B Dobyns.

At least 91 records · Page 5Linked to original sources

Diffuse polymicrogyria associated with an unusual pattern of multiple congenital anomalies including turribrachycephaly and hypogenitalism.

A newborn male infant born to consanguineous parents was found to have diffuse polymicrogyria associated with an unusual pattern of congenital anomalies including microbrachycephaly, turricephaly, blepharophimosis, microstomia with maxillary retrusion and mandibular prognathism, micropenis with cryptorchidism, camptodactyly and adducted thumbs, and a progeroid appearance. The combination of manifestations in our patient represents a unique form of polymicrogyria with congenital anomalies, probably representing a new syndrome.

Abnormalities, Multiple↗

Variable phenotype of rapid-onset dystonia-parkinsonism.

Rapid-onset dystonia-parkinsonism (RDP) is an autosomal dominant disorder characterized by the rapid onset of dystonic spasms and parkinsonism over a period of a few hours to weeks after their onset. We have seen two additional members of this previously reported family with RDP who present with a more gradual progression of their disorder over 6-18 months. One of these individuals experienced the rapid progression of symptoms 2 years after an initial stabilization of his condition. The RDP phenotype is variable, and presentation may be gradual in some cases. Cerebrospinal fluid neurotransmitter levels in these two and other family members suggest involvement of the dopaminergic pathways in RDP.

Adolescent↗

Olivopontocerebellar atrophy leading to recognition of carbohydrate-deficient glycoprotein syndrome type I.

The carbohydrate-deficient glycoprotein (CDG) syndromes are a group of genetic multisystem disorders with invariable involvement of the nervous system including severe olivopontocerebellar atrophy. We report two sets of sibs in whom the diagnosis of CDG syndrome type 1 was recognized at an older age because of marked olivopontocerebellar atrophy seen on MRI. Previous CT findings were interpreted as showing Dandy-Walker malformation. Three of the patients are also among the oldest reported with this syndrome.

Adult↗

Congenital pontocerebellar atrophy in three patients: clinical, radiologic and etiologic considerations.

We report three patients with severe pontocerebellar atrophy (PCA) associated with a variable degree of cerebral atrophy. The clinical features consisted of progressive microcephaly, central hypotonia, visual impairment, abnormal eye movements and delayed psychomotor development. These are similar but not identical to the features of pontocerebellar hypoplasia type 2 described by Barth. The picture also differs from the classical form of autosomal dominant olivopontocerebellar atrophy. While in two patients the disease seemed to be genetic with highly suspicious autosomal recessive inheritance, the etiology in the third patient was probably nongenetic. We suggest that PCA is a morphologic entity with distinct radiologic features but variable clinical, pathophysiologic and etiologic backgrounds.

Cerebellum↗

Autosomal dominant torsion dystonia with onset in infancy.

We report a man and his daughter who had onset of dystonia during the first year of life, primarily involving their legs and consisting of both sustained postures and rhythmical 2-3 Hz twisting movements. They also had eccentric and irregularly shaped pupils, but no other neurological abnormalities. This disorder differs from all familial dystonia syndromes described in the literature, including classic idiopathic torsion dystonia, which has a later age of onset. This disorder probably represents a new autosomal dominant dystonia syndrome.

Adolescent↗

A classification scheme for malformations of cortical development.

Malformations of the cerebral cortex are being recognized more frequently as a cause of epilepsy, developmental delay, neurological deficits, and mental retardation. Nonetheless, a standard nomenclature and classification system of these malformations, based upon state-of-the art knowledge derived from genetics, embryology, imaging, and pathology, has not been devised. In this manuscript, we propose such a classification system. Moreover, we have constructed the system such that both the framework and the classifications themselves are flexible and can be adapted as our knowledge of the embryology, genetics, imaging, and pathology of these disorders advances. We believe that the use of this classification system will help both clinicians and researchers to understand and think about these disorders and their causes better. In turn, we hope that this improved understanding will lead to further refinements in classification, to advances in our knowledge and, ultimately, to improvements in therapy.

Brain Damage, Chronic↗

Cobblestone lissencephaly with normal eyes and muscle.

Cobblestone lissencephaly is the characteristic brain malformation observed in Fukuyama congenital muscular dystrophy (FCMD), muscle-eye-brain disease (MEB), and Walker-Warburg syndrome (WWS). The diagnostic criteria for all three require the presence of congenital muscular dystrophy, and criteria for MEB and WWS require retinal abnormalities. We report three patients from two consanguineous families of Middle Eastern origin with cobblestone lissencephaly but no abnormalities of the eyes or muscle. Based on the current diagnostic criteria for the cobblestone lissencephaly syndromes, this disorder must be classified separately from the others, but it may well be allelic to MEB and WWS. Linkage studies have excluded the gene for this disorder from the region of the FCMD gene on chromosome 9q31-32.

Adolescent↗

X-linked malformations of neuronal migration.

Malformations of neuronal migration such as lissencephaly (agyria-pachygyria spectrum) are well-known causes of mental retardation and epilepsy that are often genetic. For example, isolated lissencephaly sequence and Miller-Dieker syndrome are caused by deletions involving a lissencephaly gene in chromosome 17p13.3, while many other malformation syndromes have autosomal recessive inheritance. In this paper, we review evidence supporting the existence of two distinct X-linked malformations of neuronal migration. X-linked lissencephaly and subcortical band heterotopia (XLIS) presents with sporadic or familial mental retardation and epilepsy. The brain malformation varies from classical lissencephaly, which is observed in males, to subcortical band heterotopia, which is observed primarily in females. The XLIS gene is located in chromosome Xq22.3 based on the breakpoint of an X-autosomal translocation. Bilateral periventricular nodular heterotopia (BPNH) usually presents with sporadic or familial epilepsy with normal intelligence, primarily in females, although we have evaluated two boys with BPNH and severe mental retardation. The gene for BPNH has been mapped to chromosome Xq28 based on linkage studies in multiplex families and observation of a subtle structural abnormality in one of the boys with BPNH and severe mental retardation.

Adult↗

Autosomal dominant optic nerve colobomas, vesicoureteral reflux, and renal anomalies.

We describe a father and 3 sons with optic nerve colobomas, vesicoureteral reflux, and renal anomalies. The youngest son had congenital renal failure and ultimately underwent renal transplantation. The father and one son had high frequency hearing loss. There were no other affected relatives. We conclude that the association of optic nerve colobomas, renal anomalies, and vesicoureteral reflux comprises a unique autosomal dominant syndrome. Molecular investigations have determined this disorder to be associated with a single nucleotide deletion in the PAX2 gene.

Abnormalities, Multiple↗

Albright hereditary osteodystrophy and del(2) (q37.3) in four unrelated individuals.

Albright hereditary osteodystrophy (AHO) is a condition with characteristic physical findings (short stature, obesity, round face, brachydactyly) but variable biochemical changes (pseudohypoparathyroidism, pseudopseudohypoparathyroidism). Most patients with AHO have decreased activity of the guanine nucleotide-binding protein (GS protein) that stimulates adenylyl cyclase. The gene encoding the alpha subunit of the GS protein (GNAS1) has been mapped to the long arm of chromosome 20. We describe 4 unrelated individuals with apparent AHO, associated with small terminal deletions of chromosome 2. All 4 patients had normal serum calcium levels consistent with pseudopseudohypoparathyroidism. Del(2) (q37) is the first consistent karyotypic abnormality that has been documented in AHO [Phelan et al., 1993: Am J Hum Genet 53:484]. The finding of the same small terminal deletion in 4 unrelated individuals with a similar phenotype suggests that a gene locus in the 2q37 region is important in the pathogenesis of Albright syndrome. The association of Albright syndrome and the GNAS1 locus on chromosome 20 is well documented. The observation of a second potential disease locus on chromosome 2 may help explain the heterogeneity observed in this disorder.

Adolescent↗

Previously apparently undescribed syndrome: shallow orbits, ptosis, coloboma, trigonocephaly, gyral malformations, and mental and growth retardation.

We describe 2 children with severe ptosis, trigonocephaly, broad nasal bridge, and major brain malformation. A total of 8 children have been reported who share most of these findings. Two of the individuals have had identical pericentric inversions involving chromosome 2p12-q14. These cases appear to represent a unique malformation syndrome.

Abnormalities, Multiple↗

Agenesis of the corpus callosum and Dandy-Walker malformation associated with hemimegalencephaly in the sebaceous nevus syndrome.

The sebaceous nevus syndrome is sometimes associated with hemimegalencephaly and a group of related abnormalities including ipsilateral gyral malformation, mental retardation, seizures, especially infantile spasms, and facial hemihypertrophy. This combination has been described as the "neurological variant of epidermal nevus syndrome." Other brain malformations have been reported only rarely. We report on a child with a subtle sebaceous nevus associated with hemimegalencephaly who also had agenesis of the corpus callosum and Dandy-Walker malformation.

Abnormalities, Multiple↗

Congenital muscular dystrophies: clinical review and proposed classification.

The clinical spectrum of the congenital muscular dystrophies is reviewed using as a sample population 10 Sicilian patients with various clinical subtypes. A comprehensive classification scheme for the muscular dystrophies is presented based on recent advances in our understanding of this heterogeneous group of syndromes.

Biopsy↗

Mutation of the PAX2 gene in a family with optic nerve colobomas, renal anomalies and vesicoureteral reflux.

Paired box (PAX) genes play a critical role in human development and disease. The PAX2 gene is expressed in primitive cells of the kidney, ureter, eye, ear and central nervous system. We have conducted a mutational analysis of PAX2 in a family with optic nerve colobomas, renal hypoplasia, mild proteinuria and vesicoureteral reflux. We report a single nucleotide deletion in exon five, causing a frame-shift of the PAX2 coding region in the octapeptide domain. The phenotype resulting from the PAX2 mutation in this family was very similar to abnormalities that have been reported in Krd mutant mice. These data suggest that PAX2 is required for normal kidney and eye development.

Abnormalities, Multiple↗

Lissencephaly and other malformations of cortical development: 1995 update.

Neuronal migration disorders are a group of malformations of the brain which primarily affect development of the cerebral cortex. The best known of these is lissencephaly (smooth brain). Most types result from incomplete neuronal migration to the cortex during the third and fourth months of gestation. In this review, we describe and illustrate the different types of neuronal migration disorders. We also review the many different genetic syndromes associated with neuronal migration disorders. Over 25 syndromes with lissencephaly or other neuronal migration disorders have been described. Among them are syndromes with several different patterns of inheritance including chromosomal or new mutation autosomal dominant, autosomal recessive, X-linked and unknown. Genetic counseling thus differs greatly between syndromes. The genes responsible for several of the lissencephaly syndromes have been mapped. X-linked lissencephaly has tentatively been mapped to chromosome Xq22 based on observation of a single X-autosomal translocation in a girl. Both Miller-Dieker syndrome and isolated lissencephaly sequence (in many patients) were mapped to chromosome 17p13.3 by detection of deletions and other structural chromosome rearrangements. Fukuyama congenital muscular dystrophy was mapped to chromosome 9q31-33 by homozygosity mapping.

Abnormalities, Multiple↗

Childhood stroke and lupus anticoagulant.

Despite extensive evaluation, the cause of many childhood ischemic strokes remains unexplained. Two children are reported with stroke and lupus anticoagulant. Both had family members with features of the antiphospholipid antibody syndrome. Children with unexplained ischemic stroke should be evaluated for lupus anticoagulant and anticardiolipin antibodies.

Antiphospholipid Syndrome↗