Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on a case of a 9-month-old female infant with a direct duplication of the 7p13-p22.1 chromosome region diagnosed by combining conventional cytogenetic, FISH, and multicolor banding (MCB) studies. Traditional G-banding detected a partial 7p duplication, which was further demonstrated to be entirely of chromosome 7 origin by using a whole chromosome paint for chromosome 7, and derived from 7p13-p22.1 by MCB. The infant presented with characteristic dysmorphic features, psychomotor retardation, and generalized hypotonia. The phenotypic manifestations of partial 7p trisomy with or without other chromosome involvement are briefly reviewed. Our observations in combination with other cases confirm that 7p trisomy due to dir dup(7p) can be regarded as a defined chromosome syndrome.
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PMID:A report of pure 7p duplication syndrome and review of the literature. 1710 60

A small supernumerary marker chromosome (SMC) was observed in a girl with severe developmental delay. Her dysmorphism included prominent forehead, hypertelorism, down-slanting palpebral fissures, low-set/large ears, and flat nasal bridge with anteverted nares. This case also presented hypotonia, hypermobility of joints, congenital heart defect, umbilical hernia, failure to thrive, and seizures. The SMC originated from the distal region of Xp as identified by FISH with multiple DNA probes. Staining with antibodies to Centromere Protein C (CENP-C) demonstrated a neocentromere, while FISH with an alpha-satellite DNA probe showed no hybridization to the SMC. A karyotype was described as 47,XX,+neo(X)(pter-->p22.31::p22.31-->pter), indicating a partial tetrasomy of Xp22.31-->pter. This karyotype represents a functional trisomy for Xp22.31-->pter and a functional tetrasomy for the pseudoautosomal region given that there is no X-inactivation center in the marker chromosome. The SMC was further characterized by microarray-based comparative genomic hybridization (array CGH) as a duplicated DNA fragment of approximately 13 megabase pairs containing about 100 genes. We have described here a new neocentromere with discussion of its clinical significance.
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PMID:Characterization of a neocentric supernumerary marker chromosome originating from the Xp distal region by FISH, CENP-C staining, and array CGH. 1726 94

We report the second case of a child with trisomy of the entire short arm of chromosome 17 secondary to a de novo duplication. Trisomy 17p in this patient resulted from a duplication, localized to the distal region of the long arm of the same chromosome, an abnormality not previously described. This cytogenetic abnormality was confirmed using whole chromosome paint, subtelomeric and Smith-Magenis probes by fluorescence in situ hybridization (FISH) analysis. The child presented with phenotypic features previously described in trisomy 17p, including some specific facial dysmorphia, microcephaly, growth retardation, hypotonia, short webbed neck, congenital heart defect, minor abnormalities of the hands, agenesis of the corpus callosum and abnormalities of the iris. Iris alterations and defects involving the left side of heart and the aorta also may represent truly clinical hallmarks of this cytogenetic abnormality. In conclusion, this cytogenetic anomaly seems to represent a severe malformation entity with a poor prognosis and a recognizable clinical pattern that justifies the use of the term "17p trisomy syndrome" suggested previously by other authors.
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PMID:Report of a child with a complete de novo 17p duplication localized to the terminal region of the long arm of chromosome 17. 1750 5

We describe a 4-year-old boy with various facial dysmorphic features such as downslanting palpebral fissures, ptosis, hypertelorism, broad nasal bridge, small and low-set ears, broad philtrum, and micrognathia. In addition, profound mental retardation, myopia, muscular hypotonia as well as genital and cardiovascular abnormalities are also present. Refinement of the breakpoints by cytogenetic techniques, in particular the increase of banding resolution in conventional cytogenetic analysis, has enabled the correct diagnosis, as proven by fluorescence in situ hybridisation (FISH) using whole chromosome painting and single copy probes. We were able to demonstrate an unbalanced translocation that the patient inherited from his father resulting in a submicroscopic monosomy 16p13.3 and a trisomy 2p24.2-pter.
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PMID:Distal monosomy 16p13.3/distal trisomy 2p24.2-pter: molecular-cytogenetic characterisation and phenotype. 1751 97

Polymalformative syndromes are always a clinical challenge for their complexity and sometimes for their rarity. Authors present the case of a girl with peculiar facies, macrocephaly, axial hypotonia, and severe development delay. Cerebral magnetic resonance showed polymicrogyria. Cytogenetics revealed a 46,XX,der(1)(qter-->p36.13::q42.3-->qter) karyotype. This is the third case described to date. Isolated partial deletions or trisomy, although rare, are more frequently reported. None of these genetic findings has ever been related with polymicrogyria. Molecular cytogenetic characterization was in this case of great value.
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PMID:Bilateral perisylvian polymicrogyria and chromosome 1 anomaly. 1756 May 7

Mosaic variegated aneuploidy (MVA) is a rare condition characterized by multiple trisomies, rarely monosomies, and a non-specific phenotype including microcephaly, growth and mental retardation, mild malformations, and an increased risk of malignancy. We describe a patient with MVA in whom trisomy 19 mosaicism was originally suspected. The patient was the product of an uncomplicated term pregnancy and delivery. Significant findings were mental retardation, obesity, mild epicanthal folds, tapering fingers, relatively small hands and feet, alternating exotropia, nasal speech limited to short phrases, and generalized hypotonia. There is no family history for birth defects, mental retardation, or consanguinity. The initial peripheral blood chromosome study showed trisomy 19 in 4 of 31 metaphase cells. Because mosaic trisomy 19 is rare, the study was extended to 100 cells, wherein two cells with trisomy 8 were identified. A second blood karyotype was obtained and found to be 47,XX,+8[3]/47,XX,+19[3]/47,XX, +18[2]/47,XX,+9[1]/46,XX[91]. Skin fibroblast chromosome studies revealed a 46,XX karyotype in 120 cells examined. There was no evidence of premature centromere separation. Mutations in the BUB1B gene that encodes a key mitotic spindle checkpoint protein have been described in MVA; however, no mutations of this gene were identified in our patient. This case illustrates the importance of considering other possibilities when confronted with an extremely rare diagnosis such as mosaic trisomy 19. In addition, it shows the importance of not simply interpreting a low percentage of multiple aneuploidies as cell culture artifact, because an additional work-up to rule out MVA may be warranted since this diagnosis is associated with an increased risk of malignancy.
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PMID:Mosaic variegated aneuploidy without microcephaly: implications for cytogenetic diagnosis. 1763 82

Mosaic trisomy 20 is one of the more common cytogenetic abnormalities found on amniocentesis or chorionic villus sampling. Studies have shown that outcome is normal in 90-93% of prenatally diagnosed cases. There are however, reports in the literature of children with mosaic trisomy 20 described as having an assortment of dysmorphic features and varying levels of developmental delay. Unfortunately, the literature has not defined a specific phenotype for this entity. Here we report on three patients with mosaic trisomy 20, two of whom were identified prenatally. Over a number of years of follow-up it has become apparent that there are some striking similarities among the three. Comparison between our patients and the literature cases indicates a more consistent phenotype than has previously been suggested. Recurring features include; spinal abnormalities (including spinal stenosis, vertebral fusion, and kyphosis), hypotonia, lifelong constipation, sloped shoulders, and significant learning disabilities despite normal intelligence. These findings may be overlooked on routine history and physical exam or assumed to be standard pediatric problems. It is not our intention to suggest that there is a distinctive face for this entity but to suggest that a subtle phenotype does exist. We have attempted to identify a set of findings for which any child diagnosed with mosaic trisomy 20 should be assessed or followed even in the presence of an apparently normal physical exam at birth.
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PMID:Expanding the phenotype of mosaic trisomy 20. 1820 70

Small supernumerary marker chromosomes are present in about 0.05% of the human population. In approximately 28% of persons with these markers (excluding the approximately 60% derived from one of the acrocentric chromosomes), an abnormal phenotype is observed. We report on a 3-month-old girl with intrauterine growth retardation, craniofacial features, hypotonia, partial coloboma of iris and total anomalous pulmonary venous return. Cytogenetic analysis showed the presence of a supernumerary marker chromosome, identified by fluorescence in situ hybridization as part of chromosome 22, and conferring a proximal partial trisomy 22q22.21, not encompassing the DiGeorge critical region (RP11-154H4 + , TBX1-). This observation adds new information relevant to cat eye syndrome and partial trisomy of 22q.
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PMID:Partial trisomy of chromosome 22 resulting from a supernumerary marker chromosome 22 in a child with features of cat eye syndrome. 1855 51

We report on a 26-year-old woman with microcephaly, typical facial features of 9q subtelomeric deletion syndrome, exophthalmos, contractures of elbow and knee joints, severe muscular hypotonia, no ability to walk, and no speech development. Array CGH revealed a cryptic 9q34.3 deletion and 2p25.2-p25.3 duplication transmitted by her mother, who was carrying a balanced translocation of chromosomes 2p and 9q. There are about 50 reported cases of deletions of the subtelomeric part of chromosome 9q, however, duplications of only the terminal part of chromosome 2p are rare. Neuroblastoma, diaphragmatic hernia, neural tube defects, broncho-pulmonary abnormalities, and congenital heart defects are conditions associated with partial trisomy of larger fragments of 2p. To our knowledge there is only one case described with an isolated duplication as distal as in the patient reported here. Joint contractures and exophthalmos observed in this patient are also seen in our patient. These features are not allegeable by the deletion 9q34.3 identified in the patient reported here and may be a hint that terminal duplication of 2p could be associated with exophthalmos and contractures.
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PMID:A cryptic unbalanced translocation t(2;9)(p25.2;q34.3) causes the phenotype of 9q subtelomeric deletion syndrome and additional exophthalmos and joint contractures. 1867 47

Wolf-Hirschhorn syndrome (WHS) is a well-known multiple congenital anomalies/mental retardation syndrome, firstly described in 1961 by Cooper and Hirschhorn. Its frequency is estimated as 1/50,000-1/20,000 births, with a female predilection of 2:1. The disorder is caused by partial loss of material from the distal portion of the short arm of chromosome 4 (4p16.3), and is considered a contiguous gene syndrome. No single gene deletions or intragenic mutations have been shown to confer the full WHS phenotype. Since the disorder was brought to the attention of geneticists, many additional cases have been published. Only in 1999, however, were the first data on the natural history brought to the attention of the medical community. The purpose of the present study is to help delineate in more detail and over a longer period of time, the natural history of WHS, in order to establish appropriate health supervision and anticipatory guidance for individuals with this disorder. We have collected information on 87 patients diagnosed with WHS (54 females and 33 males) both in USA and Italy. Age at first observation ranged between newborn and 17 years. Twenty patients have been followed from 4 months to 23 years. The deletion proximal breakpoint varied from 4p15.32 to 4p16.3, and, by FISH, was terminal and included both WHSCR. Deletion was detected by standard cytogenetics in 44/87 (50.5%) patients, whereas FISH was necessary in the other 43 (49.5%). Array-CGH analysis at 1 Mb resolution was performed in 34/87 patients, and, in 15/34 (44%), showed an unbalanced translocation leading to both a 4p monosomy and a partial trisomy for another chromosome arm. Six more patients had been previously shown to have an unbalanced translocation by karyotype analysis or FISH with a WHS-specific probe. Sixty-five of 87 patients had an apparent pure, de novo, terminal deletion; and 1/87 a tandem duplication of 4p16.1p16.3 associated with 4p16.3pter deletion. Age at diagnosis varied between 7 months gestation and 16 years. Ninety-three percent had a seizure disorder with a good outcome; 80% had prenatal onset growth deficiency followed by short stature and slow weight gain; 60% had skeletal anomalies; 50% had heart lesions; 50% had abnormal tooth development; and 40% had hearing loss. Distinctive EEG findings were seen in 90%. Structural CNS anomalies were detected in 80%. Global developmental delay of varying degrees was present in all patients. Almost 50% was able to walk either alone or with support. Hypotonia was present in virtually all patients. A global improvement was observed in all individuals, over time. Our survey has also shown how the characteristic facial phenotype tends to be less pronounced in those patients with a smaller deletion, and microcephaly is not observed in the patients with certain cryptic unbalanced translocations.
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PMID:Update on the clinical features and natural history of Wolf-Hirschhorn (4p-) syndrome: experience with 87 patients and recommendations for routine health supervision. 1893 24


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