1/267. Congenital hypomyelinating neuropathy: two patients with long-term follow-up.The authors report the long-term prospective follow-up of two unrelated females with congenital hypomyelinating neuropathy (CHN) and review previously reported cases. The authors' first patient presented with neonatal hypotonia and extremely slow nerve conduction velocities. sural nerve biopsy revealed profound hypomyelination, without inflammation or evidence of myelin breakdown. She is now 9 years of age, and her motor function has continued to improve. Follow-up nerve-conduction velocities are unchanged. The authors' second patient presented at 5 months with hypotonia. Nerve-conduction velocities were extremely slow, and sural nerve biopsy revealed severe hypomyelination, with no inflammation or evidence of myelin breakdown. She is now 5 years of age and has also demonstrated improved motor function. Repeated nerve-conduction velocities are unchanged. Both patients have normal cognitive development. Molecular genetic analysis in Patient 2 disclosed a point mutation in the myelin protein zero gene; this same point mutation has been reported in three other patients diagnosed with Dejerine-Sottas syndrome (DSS) but has never been reported in a patient with CHN. Although CHN is a distinct clinical entity, it may share similar genetic features with DSS.- - - - - - - - - - ranking = 1keywords = gene (Clic here for more details about this article) |
2/267. A severely affected infant with absence of cysteinyl leukotrienes in cerebrospinal fluid: further evidence that leukotriene c4-synthesis deficiency is a new neurometabolic disorder.leukotrienes are potent oxygenated metabolites derived from the 5-lipoxygenase pathway of arachidonic acid metabolism. They comprise the cysteinyl leukotrienes (LTC4, LTD4, LTE4) and LTB4. The rate limiting step in the formation of cysteinyl leukotrienes is the conversion of LTA4 to LTC4 catalyzed by the enzyme LTC4 synthase. Recently, the first inborn error of leukotriene synthesis, LTC4-synthesis deficiency, has been identified in a patient with a fatal developmental syndrome. We report on an additional infant presenting with severe muscular hypotonia, symmetrical extension in the lower extremities and psychomotor retardation who died at the age of 6 months. Despite intensive investigations no specific diagnosis could be made. leukotrienes were subsequently analyzed in the cerebrospinal fluid. Concentrations of LTC4, LTD4 and LTE4 were below the detection limit (< 5 pg/ml) whereas LTB4 was found to be in the upper normal range. The absence of cysteinyl leukotrienes with normal LTB4 concentration in cerebrospinal fluid is unique and seems to be pathognomonic for LTC4-synthesis deficiency. Our patient most likely represents the second case described so far with this condition. This report provides further evidence that LTC4-synthesis deficiency represents a new neurometabolic disorder.- - - - - - - - - - ranking = 79.557771753567keywords = retardation (Clic here for more details about this article) |
3/267. Unknown syndrome in two male sibs with hypotonia, ptosis, hand malformations, 2/3 toes syndactyly, and mental retardation.We report two brothers from nonconsanguineous parents who share hypotonia, ptosis, high arched palate, camptodactyly, fifth fingers clinodactyly, 2/3 toes syndactyly and psychomotor retardation. Differential diagnosis, such as the Ohdo syndrome, the Morillo-Cucci syndrome, the Marden-Walker-like syndrome, and the Frydman syndrome and discussed.- - - - - - - - - - ranking = 543.11730287814keywords = retardation, mental retardation (Clic here for more details about this article) |
4/267. The novel contiguous gene syndrome of myotubular myopathy (MTM1), male hypogenitalism and deletion in Xq28:report of the first familial case.Hu et al. (1996) and Laporte et al. (1997) recently proposed a novel contiguous gene syndrome of myotubular myopathy, abnormal male genital development and deletion in Xq28. We studied a family where two male infants, both deceased, had myotubular myopathy and intersexual genitalia. Using FISH we detected in the mother a hemizygous deletion including the myotubularin gene MTM1 and F18 (a gene of yet unknown function). DNA studies with STR-markers (short tandem repeats) within and flanking the deleted segment confirmed the deletion in the family and were used for prenatal diagnosis. Our findings confirm the existence of this novel contiguous gene syndrome and support that the deletion of the F18 gene, or a neighboring gene, may cause ambiguous genitalia or severe hypospadias in males. The mother had low muscle power and marked menstrual irregularities which may indicate that she is a manifesting carrier and that the deletion may include a gene (F18 or other) for gonadal function in females.- - - - - - - - - - ranking = 3.6666666666667keywords = gene (Clic here for more details about this article) |
5/267. A previously unrecognised phenotype characterised by obesity, muscular hypotonia, and ability to speak in patients with angelman syndrome caused by an imprinting defect.The clinical features of angelman syndrome (AS) comprise severe mental retardation, postnatal microcephaly, macrostomia and prognathia, absence of speech, ataxia, and a happy disposition. We report on seven patients who lack most of these features, but presented with obesity, muscular hypotonia and mild mental retardation. Based on the latter findings, the patients were initially suspected of having prader-willi syndrome. dna methylation analysis of SNRPN and D15S63, however, revealed an AS pattern, ie the maternal band was faint or absent. Cytogenetic studies and microsatellite analysis demonstrated apparently normal chromosomes 15 of biparental inheritance. We conclude that these patients have an imprinting defect and a previously unrecognised form of AS. The mild phenotype may be explained by an incomplete imprinting defect or by cellular mosaicism.- - - - - - - - - - ranking = 232.11309889562keywords = retardation, mental retardation, gene (Clic here for more details about this article) |
6/267. The utility of the determination of CTG trinucleotide repeat length in hypotonic infants.A 9-month-old male infant was floppy from birth with nonprogressive facial and distal limb weakness and apparently normal mother and father. The facial characteristics and distribution of involvement suggested congenital myotonic dystrophy and the infant, but not the mother, had insertional myotonia in one of four muscles tested. Had the number of CTG trinucleotide repeats been tested when the presence of a congenital myotonic dystrophy-like clinical picture was first appreciated, the proper diagnosis could have been made several months earlier. The application of new molecular genetic techniques is changing the usual sequence of studies performed in the evaluation of the hypotonic infant.- - - - - - - - - - ranking = 0.33333333333333keywords = gene (Clic here for more details about this article) |
7/267. Characterization of a small supernumerary ring marker derived from chromosome 2 by forward and reverse chromosome painting.A small ring-shaped supernumerary marker chromosome (SMC) was detected in 50% of metaphase cells in an 18-month-old boy with mental retardation and multiple congenital anomalies. Conventional cytogenetic methods had failed to identify the origin of the marker. When the patient was age 11.5 years, we defined the origin of the SMC by fluorescence in situ hybridization using a battery of centromere-specific dna probes. The marker was positive with the probe for locus D2Z. More detailed characterization was achieved by using chromosome 2 arm-specific and marker-specific DNA libraries, which were constructed by microdissection of the two arms chromosome 2 and SMC with subsequent amplification of the chromosomal material by a degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR). The marker was identified as r(2)(p11.2-->q14.1). The propositus had dolichocephaly, coarse hair, low-set ears, exophthalmos, epicanthal folds, strabismus, depressed nasal bridge, high-arched palate, excess of skin on the neck, tapered fingers with mild clinodactyly, talipes varus on the right, inguinal hernia, hypogenitalism, muscular hypotonia, and mental retardation. This is the first case of SMC derived from chromosome 2 that was characterized by forward and reverse chromosome painting.- - - - - - - - - - ranking = 232.44643222895keywords = retardation, mental retardation, gene (Clic here for more details about this article) |
8/267. Borjeson-Forssman-Lehmann syndrome in a woman with skewed X-chromosome inactivation.Borjeson-Forssman-Lehmann (BFL) syndrome is an X-linked recessive disorder characterized by minor facial anomalies, obesity, epilepsy, and severe mental retardation. The phenotype of male patients is usually severe, whereas that of carriers is less severe, suggesting X-linked incompletely recessive inheritance. A recent linkage study mapped the BFL syndrome gene to Xq26-q27. The etiology of the condition in female patients with full manifestations is not known, although nonrandom X-chromosome inactivation has been considered. We recently developed an assay for X-inactivation studies based on the methylation-specific polymerase chain reaction (PCR) technique. Using the methylation-specific PCR assay, a woman with typical findings of this syndrome was shown to have an extremely skewed X-inactivation pattern. This finding suggests that the full manifestations of the BFL syndrome in carriers may be caused by skewed X inactivation with a high proportion of cells in which the x chromosome with a normal gene be inactivated, leaving the x chromosome with a mutant gene active.- - - - - - - - - - ranking = 116.88988278114keywords = retardation, mental retardation, gene (Clic here for more details about this article) |
9/267. 46, XY, del (3) (pter-->p25) syndrome: further delineation of the clinical phenotype.A boy with monosomy for the distal part of the short arm of chromosome 3 is described. The clinical features this patient has in common with the previously reported cases include pre- and post-natal growth delay, microcephaly, craniofacial dysmorphism and mental retardation. In addition, minor abnormalities not previously reported were observed, such as snapping thumbs, dorsiflected big toes, connecting anterior and posterior fontanelles at birth, nasolacrimal duct stenosis and double urethral meatus.Conclusion These five new clinical findings may help in further delineation of the syndrome and allow its early recognition. A complete revision of clinical findings published in literature is reported.- - - - - - - - - - ranking = 115.88988278114keywords = retardation, mental retardation (Clic here for more details about this article) |
10/267. Blaschkolinear malformation syndrome in complex trisomy-7 mosaicism.Results of repeated peripheral blood chromosome studies were normal in a boy with intrauterine growth retardation, short stature, moderate mental retardation, and multiple minor anomalies. At age 9 years it was recognized that the swirls of pigmentation/depigmentation on his trunk, linear streaks on his limbs, and body asymmetry were suggestive of chromosomal mosaicism. Four skin biopsies were obtained under anesthesia during a dental procedure. All showed mosaicism for a normal cell line, a line with an extra chromosome 7, and a cell line with an extra small ring. In one biopsy, there was a fourth cell line with an extra chromosome 7 and the ring. fluorescence in situ hybridization (FISH) with a chromosome 7 paint confirmed trisomy 7 and the chromosome 7 derivation of the ring. This young man's intra-uterine and postnatal growth retardation is an aneuploidy effect, whereas his asymmetry reflects a mosaicism effect that should have aroused suspicion of tissue-limited mosaicism before the development of obvious Blaschkolinear skin pigmentary dysplasia.- - - - - - - - - - ranking = 275.00542628828keywords = retardation, mental retardation (Clic here for more details about this article) |
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