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Biomedical subjects

B R Pober

Publications and source records attributed to B R Pober.

At least 19 recordsLinked to original sources
PubMed2006

Findings from aCGH in patients with congenital diaphragmatic hernia (CDH): a possible locus for Fryns syndrome.

Congenital diaphragmatic hernia (CDH) is a common and often devastating birth defect that can occur in isolation or as part of a malformation complex. Considerable progress is being made in the identification of genetic causes of CDH. We applied array-based comparative genomic hybridization (aCGH) of approximately 1Mb resolution to 29 CDH patients with prior normal karyotypes who had been recruited into our multi-site study. One patient, clinically diagnosed with Fryns syndrome, demonstrated a de novo 5Mb deletion at chromosome region 1q41-q42.12 that was confirmed by FISH. Given prior reports of CDH in association with cytogenetic abnormalities in this region, we propose that this represents a locus for Fryns syndrome, a Fryns syndrome phenocopy, or CDH.

Abnormalities, Multiple↗
PubMed2001

Novel and recurrent mutations in lamin A/C in patients with Emery-Dreifuss muscular dystrophy.

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by slowly progressive muscle wasting and weakness; early contractures of the elbows, Achilles tendons, and spine; and cardiomyopathy associated with cardiac conduction defects. Clinically indistinguishable X-linked and autosomal forms of EDMD have been described. Mutations in the STA gene, encoding the nuclear envelope protein emerin, are responsible for X-linked EDMD, while mutations in the LMNA gene encoding lamins A and C by alternative splicing have been found in patients with autosomal dominant, autosomal recessive, and sporadic forms of EDMD. We report mutations in LMNA found in four familial and seven sporadic cases of EDMD, including seven novel mutations. Nine missense mutations and two small in-frame deletions were detected distributed throughout the gene. Most mutations (7/11) were detected within the LMNA exons encoding the central rod domain common to both lamins A/C. All of these missense mutations alter residues in the lamin A/C proteins conserved throughout evolution, implying an essential structural and/or functional role of these residues. One severely affected patient possesed two mutations, one specific to lamin A that may modify the phenotype of this patient. Mutations in LMNA were frequently identified among patients with sporadic and familial forms of EDMD. Further studies are needed to identify the factors modifying disease phenotype among patients harboring mutations within lamin A/C and to determine the effect of various mutations on lamin A/C structure and function.

Adult↗
PubMed2001

Truncating mutations in FOXC2 cause multiple lymphedema syndromes.

Hereditary lymphedemas are developmental disorders of the lymphatics resulting in edema of the extremities due to altered lymphatic flow. One such disorder, the lymphedema-distichiasis syndrome, has been reported to be caused by mutations in the forkhead transcription factor, FOXC2. We sequenced the FOXC2 gene in 86 lymphedema families to identify mutations. Eleven families were identified with mutations predicted to disrupt the DNA binding domain and/or C-terminal alpha-helices essential for transcription activation by FOXC2. Broad phenotypic heterogeneity was observed within these families. The phenotypes observed overlapped four phenotypically defined lymphedema syndromes. FOXC2 appears to be the primary cause of lymphedema-distichiasis syndrome and is also a cause of lymphedema in families displaying phenotypes attributed to other lymphedema syndromes. Our data demonstrates that the phenotypic classification of autosomal dominant lymphedema does not reflect the underlying genetic causation of these disorders.

Adolescent↗
PubMed2001

46,XX gonadal dysgenesis, short stature, and recurrent metabolic acidosis in two sisters.

Gonadal (ovarian) dysgenesis in 46,XX individuals is genetically heterogeneous. We report on two sisters who, in addition to primary ovarian failure, have marked short stature and recurrent episodes of dehydration with metabolic acidosis. Studies performed during one of these episodes suggested mitochondrial dysfunction; however, results of biochemical analysis of electron transport chain activity in skeletal muscle and mitochondrial DNA studies were normal. We discuss the phenotype in relation to previously described conditions of 46,XX gonadal dysgenesis. We suggest this constellation of findings represents a new syndrome.

Acidosis↗
PubMed2001

Differences by sex in cardiovascular disease in Williams syndrome.

OBJECTIVE: To analyze the incidence and severity of cardiovascular disease in patients with Williams syndrome (WS) and to identify factors contributing to its variable expression. METHODS: Clinical data on patients with WS were collected from several WS centers. Elastin gene deletions were confirmed in all patients. Age at diagnosis, growth data, and cardiovascular diagnoses were recorded retrospectively. Cardiac diagnoses were made on the basis of echocardiographic data. The severity of supravalvular aortic stenosis was recorded by using a 4-step scale (none, mild, moderate, severe). RESULTS: Statistical analysis of the data revealed that the severity of both supravalvular aortic stenosis and total cardiovascular disease was significantly greater in male patients than female patients (P <.002 and P <.002, respectively; Kruskal-Wallis rank-sum test). This difference was not accounted for by differences in height, weight, body mass index, or head circumference. The clinical diagnosis of WS was made at a significantly younger age in male patients (P <.01, Student t test). Earlier diagnosis was partly because of increased incidence and severity of cardiovascular disease. Another determinant of early diagnosis was low body mass index. CONCLUSION: Penetrance and severity of the elastin arteriopathy in patients with WS is affected by sex. We hypothesize that differences by sex in arterial stenoses may be related to prenatal hormonal effects. Future epidemiologic and in vitro studies may provide additional insight into the pathogenetic mechanisms of these observed differences.

Adolescent↗
PubMed1999

GATA4 haploinsufficiency in patients with interstitial deletion of chromosome region 8p23.1 and congenital heart disease.

Previous studies have shown that patients with deletion of distal human chromosome arm 8p may have congenital heart disease and other physical anomalies. The gene encoding GATA-4, a zinc finger transcription factor implicated in cardiac gene expression and development, localizes to chromosome region 8p23.1. To examine whether GATA-4 deficiency is present in patients with monosomy of 8p23.1 with congenital heart disease, we performed fluorescence in situ hybridization (FISH) with a GATA4 probe on cells from a series of patients with interstitial deletion of 8p23.1. Four individuals with del(8)(p23.1) and congenital heart disease were found to be haploinsufficient at the GATA4 locus by FISH. The GATA4 gene was not deleted in a fifth patient with del(8)(p23.1) who lacked cardiac anomalies. FISH analysis on cells from 48 individuals with congenital heart disease and normal karyotypes failed to detect any submicroscopic deletions at the GATA4 locus. We conclude that haploinsufficiency at the GATA4 locus is often seen in patients with del(8)(p23.1) and congenital heart disease. Based on these findings and recent studies showing that haploinsufficiency for other cardiac transcription factor genes (e.g., TBX5, NKX2-5) causes congenital heart disease, we postulate that GATA-4 deficiency may contribute to the phenotype of patients with monosomy of 8p23.1.

Adult↗
PubMed1999

Early puberty in Williams syndrome.

Pubertal development was evaluated in nine males and 16 females with Williams syndrome (WS). Our results indicate that puberty in WS occurred earlier than in published population controls; specifically, 90% of menstruating females reached menarche and 83% of pubertal males showed Tanner III pubic hair development prior to the age of 12 years. The sequence of pubertal development was normal, bone age was always consistent with, or in excess of, chronological age, and there was evidence of central (hypothalamic-pituitary mediated) activation as the cause of early puberty in a subset of subjects.

Age of Onset↗
PubMed1998

FACL4, a new gene encoding long-chain acyl-CoA synthetase 4, is deleted in a family with Alport syndrome, elliptocytosis, and mental retardation.

We observed a family in which two boys were diagnosed with Alport syndrome, elliptocytosis, and mental retardation and carried a large deletion of the Xq22.3-q23 region, encompassing the COL4A5 gene. This suggests the possibility of a new contiguous gene syndrome. In an attempt to characterize the genes contributing to this complex phenotype, we have isolated a gene encoding a new long-chain acyl-CoA synthetase (FACL4 or LACS4) from the region deleted in these patients. Among several ESTs identified by searching the human gene map database maintained at the National Center for Biotechnology Information, using the map position as a query, only one was deleted in the patients. RACE products containing the entire ORF were subsequently generated. Northern blot analysis showed a 5-kb mRNA expressed in several tissues except for liver and lung. Brain shows a longer transcript, possibly reflecting the use of a brain-specific upstream ATG start codon. FACL4 encodes a predicted protein product of 670 amino acids (711 in brain), with a remarkable level of conservation compared to the rat acyl-CoA synthetases ACS4 and brain-specific ACS3 protein sequences. We are investigating the possibility that the absence of this enzyme may play a role in the development of mental retardation or other signs associated with Alport syndrome in the family.

Amino Acid Sequence↗
PubMed1998

Familial dup(5)(q15q21) associated with normal and abnormal phenotypes.

We studied a familial dup(5q) present in a phenotypically normal father and his monozygotic twin daughters with different abnormal phenotypes. High-resolution chromosome analysis suggested that the duplicated segment was of region q15-21, which seems to be the smallest dup(5q) reported thus far. This dup(5q) was confirmed by fluorescence in situ hybridization with a chromosome 5 painting library and 5q cosmid clones. The presence of the dup(5q) in a normal father suggested that the duplication itself may be harmless. The anomalies in the twins may be due to processes other than this chromosome change.

Chromosome Aberrations↗
PubMed1998

Alport syndrome, mental retardation, midface hypoplasia, and elliptocytosis: a new X linked contiguous gene deletion syndrome?

We describe a family with four members, a mother, two sons, and a daughter, who show clinical features consistent with X linked Alport syndrome. The two males presented with additional features including mental retardation, dysmorphic facies with marked midface hypoplasia, and elliptocytosis. The elliptocytosis was not associated with any detectable abnormalities in red cell membrane proteins; red cell membrane stability and rigidity was normal on ektacytometry. Molecular characterisation suggests a submicroscopic X chromosome deletion encompassing the entire COL4A5 gene. We propose that the additional abnormalities found in the affected males of this family are attributable to deletion or disruption of X linked recessive genes adjacent to the COL4A5 gene and that this constellation of findings may represent a new X linked contiguous gene deletion syndrome.

Abnormalities, Multiple↗
PubMed1996

Type III tracheal agenesis with familial tetralogy of Fallot and absent pulmonary valve syndrome.

We describe a female infant born at 33 weeks gestation diagnosed postnatally with a previously unreported phenotype consisting of Type III tracheal agenesis plus tetralogy of Fallot with absent pulmonary valve. She was delivered to a mother who had the same congenital heart malformation, but no detectable tracheal abnormality. We discuss possible etiologies of these malformations.

Abnormalities, Multiple↗
PubMed1996

Neurologic findings in children and adults with Williams syndrome.

Twenty-four children with Williams syndrome underwent systematic neurologic evaluations. Abnormalities of mental status, motor coordination, tone, and gait were most prevalent. Tone abnormalities varied as a function of age, with younger children frequently exhibiting decreased tone and older subjects almost exclusively having increased tone. The gait and coordination abnormalities persisted among older subjects, indicating that they were not simply maturational problems. Physicians caring for such youngsters need to be aware that a variety of neurologic abnormalities are common in Williams syndrome and may change or progress over time. Neurologic examinations that reveal findings beyond the typical pattern that we report may raise suspicion for added neurologic insult and warrant further investigation.

Adolescent↗
PubMed1995

Deletion of chromosome 2q24-q31 causes characteristic digital anomalies: case report and review.

We describe a newborn boy with multiple anomalies, including bilateral split foot and an interstitial deletion of chromosome 2 (q24.2-q31.1). Four additional cases in 2 families involving similar deletions have been reported. Bilateral digital anomalies of hands and feet were seen in all 5 cases, including a wide cleft between the first and second toes, wide halluces, brachysyndactyly of the toes, and camptodactyly of the fingers. Other common manifestations have included postnatal growth and mental retardation, microcephaly, down-slanting palpebral fissures, micrognathia, and apparently low-set ears. Bilateral digital anomalies were reported in 22 of 24 cases with deletions including at least part of region 2q24-q31. Digital anomalies were not prevalent in 18 patients with deletions of chromosome 2q not overlapping 2q24-q31. 2q31.1 appears to be the common deleted segment in all cases with significant digital anomalies, which implies the existence of one or more genes involved in distal limb morphogenesis in this region. HOXD13 and EVX2, located in the proximity of 2q31, were not deleted in our patient by Southern analysis. Bilateral digital malformations of the hands and feet associated with other anomalies should be evaluated by chromosome analysis focused at the 2q24-q31 region.

Abnormalities, Multiple↗
PubMed1995

The neuropathology of Williams syndrome. Report of a 35-year-old man with presenile beta/A4 amyloid plaques and neurofibrillary tangles.

OBJECTIVE: To study neuropathologically Williams syndrome in a 35-year-old patient. METHODS: Sections from multiple regions of the brain were examined with luxol fast blue and hematoxylineosin staining, and selected sections were stained with the silver impregnation technique (Bielschowsky technique) and Congo red. In addition, immunohistochemistry with monoclonal antibodies against glial fibrillary acidic protein, beta/A4 amyloid, paired helical filaments, and phosphorylated tau protein was performed on cortical, hippocampal, amygdaloid, and basal ganglian sections. RESULTS: No specific macroscopic or microscopic abnormalities were recognized that are specific for Williams syndrome. The histopathologic examination did, however, demonstrate the presence of Alzheimer-type changes, including beta/A4 amyloid-containing senile plaques and scattered neurofibrillary tangles in neocortex and medial temporal lobe structures (entorhinal cortex, CA1 area of the hippocampus, and amygdala). Plaques were most numerous in the amygdala (7/mm2) and in the entorhinal cortex (4/mm2). Neurofibrillary tangles were less numerous (< 1/mm2), except in the hippocampus, where approximately 2/mm2 were found. CONCLUSIONS: To our knowledge, ours represents the first neuropathologic description of a patient with Williams syndrome. Although Williams syndrome is usually sporadic, familial cases have been reported along with candidate chromosomal loci. If our findings are confirmed in additional patients with Williams syndrome, they may provide clues to other factors that are important in the pathogenesis of senile plaques (with beta/A4 amyloid deposition) and neurofibrillary tangles.

Adult↗
PubMed1995

Association of Chiari I malformation and Williams syndrome.

Two Williams syndrome patients are presented who had neurologic symptoms secondary to Chiari malformation type I. Both patients had many of the well-known medical problems found in Williams syndrome. In addition, Patient 1 developed headache, diplopia, and tinnitus at 26 years of age. Neurologic examination revealed intermittent nystagmus and brisk reflexes. Magnetic resonance imaging demonstrated Chiari malformation type I; neurologic symptoms abated following surgery. Patient 2 had a normal neurologic examination at 2 years of age except for hyperreflexia and tight heel cords. At age 10 years, she had generalized contractures, decreased strength and wasting of hand musculature, and hyperreflexia. Magnetic resonance imaging documented Chiari malformation type I. Both patients have significant dysphagia and fusion of cervical spine segments noted on radiography. Morphometric analyses of intracranial contents based on midsagittal magnetic resonance images were performed. This analysis suggests that, compared to age-matched controls, the posterior fossa size is selectively diminished in Williams syndrome, whereas the cerebellum is normal in size. This "mismatch" between the size of the posterior fossa bony compartment and its neural contents may place Williams syndrome patients at high risk for developing Chiari malformation type I.

Abnormalities, Multiple↗
PubMed1995

Ischemic stroke and intracranial multifocal cerebral arteriopathy in Williams syndrome.

We describe an otherwise healthy 2-year-old patient with Williams syndrome who had a stroke as a result of intracranial multivessel focal and segmental stenotic disease. The diagnosis of Williams syndrome was confirmed by elastin gene deletion testing. Combined magnetic resonance imaging and magnetic resonance angiography, and transcranial Doppler flow studies, were used in diagnosing and monitoring the course of the disease.

Brain Ischemia↗
PubMed1993

Renal findings in 40 individuals with Williams syndrome.

We tabulated the frequency of renal abnormalities in 40 Williams syndrome individuals presenting for medical and/or developmental assessment to a multi-disciplinary Williams syndrome program. The average age at time of assessment was 7 2/12 years. Seven individuals (7/40 = 18%) had abnormalities detected, including nephrocalcinosis = 2; marked asymmetry in kidney size = 2; small kidneys = 1; solitary kidney = 1; and pelvic kidney = 1. Renal function was also assessed. Two individuals had evidence of renal dysfunction, one secondary to nephrocalcinosis and the second due to hypercalcemia and interstitial nephritis of unclear pathogenesis. We examined the frequency of renal artery stenosis in 9 individuals who underwent abdominal angiography during cardiac catheterization. We found unilateral or bilateral mild renal artery narrowing in 4 individuals and normal renal arteries in the remaining 5. Persistent hypertension occurred in only 2 individuals and did not correlate with renal artery status. We conclude that intrinsic renal anomalies, as well as problems secondary to hypercalcemia, occur with sufficient frequency to warrant baseline renal screening in all individuals with Williams syndrome.

Abnormalities, Multiple↗