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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

3 cases of the 18q- syndrome, 2 boys and 1 girl, are presented, and a comparison with data from the literature is given. The following features are typical of the syndrome: short stature, mental retardation, muscular hypotonia, a peculiar dysmorphia of the face and ears, cryptorchidism and small scrotum in males, proximally implanted thumbs, tapering fingers, excess of whorls on the fingertips, and dorsally implanted second toes. Midface hypoplasia with hypertelorism and cleft palate, as well as strabismus, were present in 2 of our patients, whereas all 3 showed nystagmus and prominence of anthelix and antitragus. In addition, 2 patients exhibited narrow ear canals and impaired hearing. One patient had coloboma of the iris and choroid, pale optic discs, and cleft lip; another had umbilical and inguinal hernias. Two cases represented de novo deletions of the long arm of chromosomes 18, whereas the karyotype of the father of third case revealed a balanced translocation t(15;18)(q24;q21).
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PMID:Structural aberrations of chromosome 18. II. The 18q- syndrome. Report of three cases. 111

Following an introductory illustration of the clinical characteristics of the 18q syndrome (De Grouchy syndrome), the paper describes the treatment carried out in a young patient with harelip and cleft palate in addition to chromosomopathy. Although the facial malformation and the karyotype with the deletion of a portion of the long arm of chromosome 18 were diagnosed in utero, the parents, having been correctly informed of the mental retardation usually associated with this syndrome and the possibility of surgical correction of the facial malformation, decided not to abort. The case offers an occasion for analysing the various stages and results obtained to date using a multi-specialised diagnostic approach and functional and surgical treatment of the harelip and cleft palate which have enabled much of the congenital handicap to be corrected.
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PMID:[The functional and surgical rehabilitative treatment of cleft lip and cleft palate in a case of the syndrome of the deletion of the long arm of chromosome 18 diagnosed in utero]. 175 34

This is the first reported case of dystonia with a partial deletion of the long arm (q) of chromosome 18. Neurologic findings in the 18q- syndrome include mental retardation, seizures, nystagmus, incoordination, tremor, and chorea. A 36-year-old woman with an 18q terminal deletion [karyotype 46,XX,del(18)(q22.2)] had hypothyroidism, diabetes mellitus, borderline intelligence, short stature, short neck, sensorineural hearing loss, and sensorimotor axonal neuropathy. Parents' karyotypes were normal. She had had incoordination and writing difficulty since childhood. Posturing and tremor of the head began at age 16, followed by arm tremors. She had jaw deviation and tremor, neck tremor with retrocollis, involuntary pronation of the right arm, coarse postural and severe action tremor, and tight pen grip with dystonic wrist extension on writing. The 18q- syndrome should be added to the list of genetic causes of secondary dystonia. A karyotype analysis should be considered in secondary dystonias, particularly when there are associated features such as short stature and endocrinopathies.
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PMID:Dystonia in a patient with deletion of 18q. 756 32

The 18q- syndrome is one of several terminal deletion disorders that occur in humans. Previous G-banding studies suggest that the loss of a critical band, 18q21.3, results in mental retardation, craniofacial anomalies, and metabolic defects. However, it is difficult to reconcile the consistent loss of a single region with the large variability in clinical phenotype. The purpose of this study was to reassess the extent of chromosomal loss in a cohort of 17 18q- syndrome patients by using fluorescent-activated chromosome sorting, PCR, and FISH. Bivariate flow karyotypes revealed heterogeneity among the deletions; they ranged in size from 9 to 26 Mb. To confirm this heterogeneity at a molecular level, deleted and normal chromosomes 18 of six patients were collected by flow sorting, preamplified by random priming, and assayed for marker content by the PCR. This analysis defined five unique breakpoints among the six patients. We conclude that the terminal deletions in the 18q- syndrome occur over a broad region spanning the interval from 18q21.2 to 18q22.2. Our results suggest that the variability in clinical phenotype may be more representative of a contiguous-gene syndrome with a baseline deficit of 18q22.2-qter than of the loss of a single critical region within 18q21.3.
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PMID:The 18q- syndrome: analysis of chromosomes by bivariate flow karyotyping and the PCR reveals a successive set of deletion breakpoints within 18q21.2-q22.2. 771 3

The 18q- syndrome is one of the commonest deletion syndromes. Clinical characteristics are variable but may include: hypotonia, tapered digits, "carp-like" mouth, mental retardation, and hearing impairment. Growth failure (GF; both weight and height < 3%) was reported in 80% of affected individuals. We evaluated growth hormone (GH) sufficiency in 5 18q- syndrome patients, 3 of whom had growth failure (< 3% weight and height); the remaining 2 had normal growth parameters. Laboratory evaluation of growth included measurement of IGF-1, IGFBP-3, bone ages and GH response to pituitary provocative agents. Three patients failed to produced adequate GH following stimulation testing. Of 3 patients with inadequate GH production, 1 had normal growth (above 3%). Only 1 of 5 patients had normal GH production and normal growth parameters. Our findings to date suggest that GH deficiency is common in individuals with the 18q- syndrome. The pathogenesis of this finding is unknown. We postulate that a gene(s) on 18q is involved in GH production.
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PMID:Growth hormone deficiency associated in the 18q deletion syndrome. 906 76

The 18q- syndrome is a deletion syndrome that is characterized by mental retardation, hearing loss, midfacial hypoplasia, growth deficiency, and limb anomalies. Most patients with this syndrome have deletions from 18q21-qter. We report on three patients with deletions of 18q23. A mother and daughter with identical deletions of 18q23 have many of the typical features of the 18q- syndrome, including midfacial hypoplasia and hearing loss. In contrast, the third patient has few of the symptoms of the 18q- syndrome. A contig of the 18q23 region was generated to aid in the mapping of the breakpoints. FISH was used to map both breakpoints to the same YAC clone. Furthermore, somatic-cell hybrids from the daughter and the third patient were isolated. The mapping results of sequence-tagged sites relative to the two breakpoints were identical, suggesting that the two deletion breakpoints map very close to one another. The analyses of these patients demonstrate that the critical region for the 18q- syndrome maps to 18q23 but that a deletion of 18q23 does not always lead to the clinical features associated with the syndrome. These patients demonstrate the wide phenotypic variability associated with deletions of 18q.
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PMID:Molecular characterization of patients with 18q23 deletions. 910 32

Magnetic resonance imaging (MRI) and MRI relaxometry were used to investigate disturbed brain myelination in 18q- syndrome, a disorder characterized by mental retardation, dysmorphic features, and growth failure. T1-weighted and dual spin-echo T2-weighted MR images were obtained, and T1 and T2 parametric image maps were created for 20 patients and 12 controls. MRI demonstrated abnormal brain white matter in all patients. White matter T1 and T2 relaxation times were significantly prolonged in patients compared to controls at all ages studied, suggesting incomplete myelination. Chromosome analysis using fluorescence in situ hybridization techniques showed that all patients with abnormal MRI scans and prolonged white matter T1 and T2 relaxation times were missing one copy of the myelin basic protein (MBP) gene. The one patient with normal-appearing white matter and normal white matter T1 and T2 relaxation times possessed two copies of the MBP gene. MRI and molecular genetic data suggest that incomplete cerebral myelination in 18q- is associated with haploinsufficiency of the gene for MBP.
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PMID:Magnetic resonance imaging demonstrates incomplete myelination in 18q- syndrome: evidence for myelin basic protein haploinsufficiency. 925 79

We report on a mother and child with a paracentric inversion of the long arm of chromosome 18: 46,XX,inv(18)(q21.1q23). The child had findings in common with those seen in 18q- syndrome including: microcephaly, epicanthal folds, midface hypoplasia, and abnormally modeled ears, dermatoglyphic whorls on fingertips, clubfeet, hearing loss, and developmental delay. The mother and several maternal relatives had mild mental retardation and hearing loss. Magnetic resonance imaging of the child's brain showed abnormal myelination. Molecular studies including PCR-based markers for the MBP locus and fluorescent in situ hybridization with a P1 genomic clone on mother and child demonstrated only one copy of the MBP locus (18q23) with the deletion extending beyond the MBP locus. Therefore, the deletion in the MBP region may account for the abnormal myelination seen in the patient. The other clinical findings, including mental retardation and hearing loss in this family, may reflect disruption of distal or proximal genes within the deleted MBP region or at the more proximal breakpoint 18q21.1, and may represent a contiguous gene syndrome. Further study of this family may help define those genes functioning in the MBP region that contribute to the phenotype of 18q- syndrome.
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PMID:Chromosome 18q paracentric inversion in a family with mental retardation and hearing loss. 955 94

We describe a 6 1/2-year-old girl with an interstitial deletion of chromosome arm 18q (18q21.1q22.3). Her clinical manifestations are a combination of those found in monosomy 18q syndrome and those of Rett syndrome. Cytogenetic analysis demonstrated a deletion of the long arm of chromosome 18, defined by molecular analysis with polymorphic markers as a de novo interstitial deletion, paternally derived. The findings typical of the 18q- syndrome included mental retardation, midface hypoplasia, and hypoplasia of labia majora, and those typical of Rett syndrome were severe mental retardation, autistic behavior, inappropriate hand-washing movements, epilepsy, attacks of sighing and hyperventilation, and progressive scoliosis since the age of 5 years. She did not have microcephaly, and the mental delay was obvious from an early age without a period of normal development, which makes the diagnosis of Rett syndrome atypical. Previously, a girl with mosaicism for a monosomy 18q associated with Rett syndrome has been described. That girl had a terminal deletion of chromosome 18q, which seems to coincide in part with that in the present girl. It is possible that genes in the distal region of 18q are involved in the etiology of Rett syndrome.
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PMID:Monosomy 18q syndrome and atypical Rett syndrome in a girl with an interstitial deletion (18)(q21.1q22.3). 1005 Nov 71

We report three generation family that includes two patients with severe mental retardation and additional anomalies who have been studied, clinically, cytogenetically, and molecular cytogenetically. A clinical diagnosis could not be made in the propositus, but facial anomalies of Down syndrome (DS) were recognized in the maternal uncle of the propositus. In view of a strong family history of recurrent miscarriage, a familial translocation was highly suggestive. Standard cytogenetic analysis did not reveal any abnormalities. Fluorescence in situ hybridization (FISH) using subtelomeric DNA probes identified a familial cryptic translocation of chromosomes 18 and 21, resulting in partial trisomy 21 and partial monosomy 18q in both patients. FISH analysis of obligate carriers demonstrated a balanced translocation between the terminal parts of 18q and 21q. Including this family, a total of six different familial cases with cryptic or subtle subtelomeric translocations of chromosome 21q has been reported, of which three involved terminal parts of chromosome 18q. The remarkable similarity of the chromosomal breakpoints of our patients and the described families prompted us to refine the breakpoints and to discuss phenotypic differences between these patients. Our results reinforce the role of cryptic subtelomeric rearrangements in patients with mental retardation associated with physical anomalies and stress the importance of FISH technology to supplement routine cytogenetics.
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PMID:Familial MCA/MR syndrome due to inherited submicroscopic translocation t(18;21)(q22.1q21.3) with breakpoint at the Down syndrome critical region. 1259 86


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