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F Greenberg

Publications and source records attributed to F Greenberg.

At least 37 records · Page 2Linked to original sources
PubMed1995

Replication banding and molecular studies of a mosaic, unbalanced dic(X;15)(Xpter-->Xq26.1::15p11-->15qter).

We present a patient with a chromosomal mosaicism involving the X chromosome. One cell line is 45,X and the other has a de novo paternally derived dicentric X;15 translocation. Her karyotype is therefore 45,X/45,X,dic(X;15)(Xpter-->Xq26.1::15p11-->15 qter) based on G-banding. The presence of 2 centromeres on the derivative X was confirmed by fluorescence in situ hybridization (FISH) and a deletion of Xq26.1-->qter was confirmed by polymerase chain reaction (PCR) using DXS52 and DXYS154. Replication banding studies indicate that the derivative X is late replicating. Based on these studies, it is unclear whether inactivation has spread to proximal 15q. The patient has a unique phenotype distinct from Ullrich-Turner or Prader-Willi syndromes, but includes ataxia and language delay which are commonly seen in Angelman syndrome. These findings are contrary to those anticipated since deficiency of paternal genes at 15q12 typically leads to Prader-Willi syndrome. Molecular analysis of PCR-based polymorphisms of chromosome 15 and X indicates that uniparental disomy is not present for the X chromosome or chromosome 15 in either cell line. It is hypothesized that her phenotype results from the interaction of the 2 abnormal genotypes. Each abnormality may be diluted by the mosaicism and, in the derivative X line, by the possible variation among cells of inactivation spreading to chromosome 15.

Abnormalities, Multiple↗
PubMed1995

De novo tandem duplication of chromosome segment 22q11-q12: clinical, cytogenetic, and molecular characterization.

We report on a case of duplication of the segment 22q11-q12 due to a de novo duplication. Molecular cytogenetics studies demonstrated this to be a tandem duplication, flanked proximally by the marker D22Z4, a centromeric alpha satellite DNA repeat, and distally by D22S260, an anonymous DNA marker proximal to the Ewing sarcoma breakpoint. The segment includes the regions responsible for the "cat-eye," Di George, and velo-cardio-facial syndromes and extends distal to the breakpoint cluster region (BCR). The clinical picture is dominated by the cardiac defects and includes findings reminiscent of "cat-eye" syndrome. These findings reinforce the hypothesis that the proximal 22q region contains dosage-sensitive genes involved in development.

Chromosome Aberrations↗
PubMed1995

Submicroscopic deletions at 22q11.2: variability of the clinical picture and delineation of a commonly deleted region.

DiGeorge anomaly (DGA) and velo-cardiofacial syndrome (VCFS) are frequently associated with monosomy of chromosome region 22q11. Most patients have a submicroscopic deletion, recently estimated to be at least 1-2 Mb. It is not clear whether individuals who present with only some of the features of these conditions have the deletion, and if so, whether the size of the deletion varies from those with more classic phenotypes. We have used fluorescence in situ hybridization (FISH) to assess the deletion status of 85 individuals referred to us for molecular analysis, with a wide range of DGA-like or VCFS-like clinical features. The test probe used was the cosmid sc11.1, which detects two loci about 2 Mb apart in 22q11.2. Twenty-four patients carried the deletion. Of the deleted patients, most had classic DGA or VCFS phenotypes, but 6 deleted patients had mild phenotypes, including 2 with minor facial anomalies and velopharyngeal incompetence as the only presenting signs. Despite the great phenotypic variability among the deleted patients, none had a deletion smaller than the 2-Mb region defined by sc11.1. Smaller deletions were not detected in patients with particularly suggestive phenotypes who were not deleted for sc11.1, even when tested with two other probes from the DGA/VCFS region.

Abnormalities, Multiple↗
PubMed1995

Dysmorphic features in patients with complex glycerol kinase deficiency.

Complex glycerol kinase deficiency is a contiguous gene syndrome consisting of a deletion of the glycerol kinase locus, together with the genes for adrenal hypoplasia congenita or Duchenne muscular dystrophy or both. We describe an infant with complex glycerol kinase deficiency and mildly dysmorphic features similar to those seen in other patients, including an "hourglass" appearance of the middle of the face; hypertelorism; rounded palpebral fissures; esotropia; wide, flattened earlobes; and a downturned mouth. The combination of medical history and characteristic facies should prompt the request for specific laboratory tests diagnostic for this potentially treatable condition.

Adrenal Insufficiency↗
PubMed1995

The gene for a human microfibril-associated glycoprotein is commonly deleted in Smith-Magenis syndrome patients.

Smith-Magenis syndrome (SMS) is a clinically recognizable multiple congenital anomaly/mental retardation syndrome associated with deletion of chromosome 17p11.2. Here we report the identification of a novel gene encoding a human microfibril-associated glycoprotein (MFAP4), which has been mapped to the SMS region. A full-length cDNA corresponding to this gene has been sequenced, and reveals a coding region of 255 amino acids. MFAP4 has a fibrinogen-like domain and shares a high level of sequence homology to a fragment of a bovine 36 kDa microfibril-associated glycoprotein. The N-terminus of the protein bears an Arg-Gly-Asp sequence that serves as the ligand motif for cell surface receptor integrin. These structural features of MFAP4 suggest that it is an extracellular matrix protein involved in cell adhesion or intercellular interactions. Deletion analysis has been conducted on 31 SMS patients by polymerase chain reaction and Southern analysis of somatic cell hybrids retaining the del(17)(p11.2) chromosome or by fluorescence in situ hybridization. The MFAP4 locus is deleted in 30 of 31 SMS patients. Thus, the function of this gene must be considered in the pathogenesis of SMS. Given our previous hypothesis that SMS is a contiguous gene syndrome, complete and exhaustive definition of the critical deletion interval and a thorough phenotype-genotype correlation is required to demonstrate the role and importance of the MFAP4 gene in SMS.

Abnormalities, Multiple↗
PubMed1995

A gene for a severe lethal form of X-linked arthrogryposis (X-linked infantile spinal muscular atrophy) maps to human chromosome Xp11.3-q11.2.

X-linked arthrogryposis Type I (X-linked infantile spinal muscular atrophy) is a rare disorder showing hypotonia, areflexia, and multiple congenital contractures (arthrogryposis) associated with loss of anterior horn cells and death in infancy. We have studied an X-linked arthrogryposis family using highly polymorphic microsatellite markers throughout the X chromosome. Meiotic breakpoint analysis (concordance analysis) based on shared regions of the founder X chromosome was successful in localizing the X-linked arthrogryposis gene to Xp11.3-q11.2. In this region, the highest two-point lod score was found with DXS991 (Zmax = 2.63, theta = 0.00). In multipoint linkage analysis covering the entire X chromosome, only the region defined by MAOB and DXS991 showed positive lod scores and all other regions showed negative lod scores. These data establish the first gene mapping assignment of an X-linked lethal form of human lower motor neuron disease.

Adolescent↗
PubMed1995

Deletions of the elastin gene at 7q11.23 occur in approximately 90% of patients with Williams syndrome.

To investigate the frequency of deletions of the elastin gene in patients with Williams syndrome (WS), we screened 44 patients by both FISH and PCR amplification of a dinucleotide repeat polymorphism. FISH was performed using cosmids containing either the 5' or the 3' end of the elastin gene. PCR analysis was performed on the patients and their parents with a (CA)n repeat polymorphism found in intron 17 of the elastin locus. Of the 44 patients screened, 91% were shown to be deleted by FISH. Using the DNA polymorphism, both maternally (39%) and paternally (61%) derived deletions were found. Four patients were not deleted for elastin but have clinical features of WS. Since deletions of elastin cannot account for several features found in WS, these patients will be valuable in further delineation of the critical region responsible for the WS phenotype. Although PCR can be useful for determining the parental origin of the deletion, our results demonstrate that FISH analysis of the elastin locus provides a more rapid and informative test to confirm a clinical diagnosis of WS. The presence of two copies of the elastin locus in a patient does not, however, rule out WS as a diagnosis.

Abnormalities, Multiple↗
PubMed1995

The human homologue of the Drosophila melanogaster flightless-I gene (flil) maps within the Smith-Magenis microdeletion critical region in 17p11.2.

The Smith-Magenis syndrome (SMS) appears to be a contiguous-gene-deletion syndrome associated with a proximal deletion of the short arm of chromosome 17 in band p11.2. The spectrum of clinical findings includes short stature, brachydactyly, developmental delay, dysmorphic features, sleep disturbances, and behavioral problems. The complex phenotypic features suggest deletion of several contiguous genes. However, to date, no protein-encoding gene has been mapped to the SMS critical region. Recently, the Drosophila melanogaster flightless-I gene, fliI, and the homologous human cDNA have been isolated. Mutations in fliI result in loss of flight ability and, when severe, cause lethality due to incomplete cellularization with subsequent abnormal gastrulation. Here, we demonstrate that the human homologue (FLI) maps within the SMS critical region. Genomic cosmids were used as probes for FISH, which localized this gene to the 17p11.2 region. Somatic-cell hybrid-panel mapping further localized this gene to the SMS critical region. Southern blot analysis of somatic-cell hybrids and/or FISH analysis of lymphoblastoid cell lines from 12 SMS patients demonstrates the deletion of one copy of FLI in all SMS patients analyzed.

Animals↗
PubMed1995

Haploinsufficiency of cytosolic serine hydroxymethyltransferase in the Smith-Magenis syndrome.

Folate-dependent one-carbon metabolism is critical for the synthesis of numerous cellular constituents required for cell growth, and serine hydroxymethyltransferase (SHMT) is central to this process. Our studies reveal that the gene for cytosolic SHMT (cSHMT) maps to the critical interval for Smith-Magenis syndrome (SMS) on chromosome 17p11.2. The basic organization of the cSHMT locus on chromosome 17 was determined and was found to be deleted in all 26 SMS patients examined by PCR, FISH, and/or Southern analysis. Furthermore, with respect to haploinsufficiency, cSHMT enzyme activity in patient lymphoblasts was determined to be approximately 50% that of unaffected parent lymphoblasts. Serine, glycine, and folate levels were also assessed in three SMS patients and were found to be within normal ranges. The possible effects of cSHMT hemizygosity on the SMS phenotype are discussed.

Abnormalities, Multiple↗
PubMed1994

Very low maternal serum chorionic gonadotropin levels in association with fetal triploidy.

OBJECTIVE: The objective of this study was to identify the parental origin of the extra haploid set of chromosomes in triploid pregnancies and to correlate the parental origin to very low levels of human chorionic gonadotropin and unconjugated estriol levels (multiple of the median < or = 0.20) and normal alpha-fetoprotein levels. STUDY DESIGN: Three triploid pregnancies were ascertained retrospectively, and three pregnancies were identified prospectively. Maternal sera samples were analyzed for levels of alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol. Deoxyribonucleic acid analysis was performed on parental bloods and fetal fibroblasts in two prospectively identified pregnancies to establish the parental origin of the extra set of chromosomes. RESULTS: Levels of alpha-fetoprotein were normal in all pregnancies. Levels of human chorionic gonadotropin were very low in five of six of pregnancies, and unconjugated estriol levels were low in three of six pregnancies. Deoxyribonucleic acid analysis indicated maternal origin of the extra haploid set of chromosomes in two triploids. CONCLUSION: When the extra haploid set of chromosomes are maternally derived, some triploid pregnancies exhibit very low levels of maternal serum human chorionic gonadotropin and unconjugated estriol with normal levels of alpha-fetoprotein.

Adult↗
PubMed1993

Williams syndrome: autosomal dominant inheritance.

Williams syndrome (WS) usually occurs sporadically. Few familial cases of Williams syndrome have been described, and those reports have often lacked photographic documentation. We describe 3 families, including a 3-year-old boy and his 34-year-old father, a 2-year-old girl and her 30-year-old mother, and a 3-year-old girl and her 31-year-old mother. None of these patients has supravalvular aortic stenosis or chromosome abnormalities. In all 3 families, the parent with Williams syndrome was diagnosed after the identification of the syndrome in the affected child.

Abnormalities, Multiple↗
PubMed1993

Clinical, cytogenetic, and molecular evidence for an infant with Smith-Magenis syndrome born from a mother having a mosaic 17p11.2p12 deletion.

We describe an infant with del(17) (p11.2p12) whose deleted chromosome was inherited from a mosaic mother. The child had manifestations consistent with Smith-Magenis syndrome. The mother appeared to be of normal intelligence and she had minimal findings of Smith-Magenis syndrome. Separation of chromosome 17 homologues in somatic cell hybrids and molecular studies confirmed the cytogenetic diagnoses and the fact that the mother was mosaic. Furthermore, molecular analysis demonstrated novel breakpoints in this family, with the deletion extending into and completely encompassing the markers duplicated in Charcot-Marie-Tooth (CMT) disease. Although this Smith-Magenis syndrome patient is completely deleted for the CMT region, her electrophysiological findings are different from those found in CMT. This is the only reported case of Smith-Magenis syndrome with transmission from a partially affected mosaic mother. Transmission of interstitial deletions from mosaic parents may be more common than thought; therefore, parental chromosomes should be examined when interstitial deletions are identified.

Abnormalities, Multiple↗
PubMed1993

Familial interstitial deletion 11(p11.12p12) associated with parietal foramina, brachymicrocephaly, and mental retardation.

Parietal foramina may be an isolated autosomal dominant trait or found in syndromes. We report on two related individuals who have multiple anomalies with parietal foramina and the deletion of 11(p11.12p12) due to the inheritance of a derivative chromosome 11 from an insertional translocation dir ins (13;11)(q14.1; p11.12p12). Results of initial chromosome analyses on the proposita and her maternal half-uncle were reported as normal. However, the clinical manifestations and family history suggested a chromosomal cause and cytogenetic studies were performed on the proposita's mother. A derivative chromosome 13 was initially identified and further evaluation documented a derivative 11 as the reciprocal product. This family illustrates the importance of performing chromosome studies on the normal intervening relatives in families with multiple affected individuals with mental retardation and minor anomalies as one of the two reciprocal products may be more easily detectable in a balanced carrier. Additionally, the finding of del(11)(p11.12p12) may provide a map location for a syndrome which includes parietal foramina.

Abnormalities, Multiple↗
PubMed1993

An association between fetal abdominal wall defects and elevated levels of human chorionic gonadotropin in mid-trimester.

We analysed maternal serum human chorionic gonadotropin (hCG) in 16 pregnancies with fetal abdominal wall defects previously identified prenatally by elevated maternal serum alpha-fetoprotein (AFP) or at birth. The AFP levels had a mean of 6.38 MOM (range 0.34-15.65), as expected with these defects. The hCG levels had a mean of 1.82 MOM (range 0.23-4.11). The hCG levels in five pregnancies (31.25 per cent) were above 2.30 MOM. Elevated levels of hCG may be associated with fetal abdominal wall defects.

Abdominal Muscles↗
PubMed1993

Multiplex PCR of three dinucleotide repeats in the Prader-Willi/Angelman critical region (15q11-q13): molecular diagnosis and mechanism of uniparental disomy.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct mental retardation disorders caused by a deficiency of paternal (PWS) or maternal (AS) contributions for chromosome 15 by either deletion or uniparental disomy (UPD). To further study the molecular mechanisms involved in these disorders and to improve molecular diagnostic methods, we have isolated three dinucleotide repeat markers in the PWS/AS critical region. An Alu-CA PCR method was used to isolate CA-repeat markers directly from yeast artificial chromosome (YAC) clones identified by probes IR4-3R (D15S11), LS6-1 (D15S113), and GABAA receptor B3 (GABRB3). Three markers with 6-11 alleles and 73-83% heterozygosities were identified and analyzed by multiplex PCR. Gene-centromere mapping was performed on a panel of ovarian teratomas of known meiotic origin, and showed the most proximal marker, IR4-3R, to be 13 cM (95% confidence limits: 7-19 cM) from the centromere of chromosome 15. Molecular diagnostic studies were performed on 20 PWS and 9 AS patients. In 17 patients with deletions, the parental origin of deletion was determined. Ten PWS patients were shown to have maternal heterodisomy. Since these markers are only 13 cM from the centromere, heterodisomy indicates that maternal meiosis I nondisjunction is involved in the origin of UPD. In contrast, two paternal disomy cases of AS showed isodisomy for all markers tested along the length of chromosome 15. This suggests a paternal meiosis II nondisjunction event (without crossing over) or, more likely, monosomic conception (due to maternal nondisjunction) followed by chromosome duplication.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗