11/147. Peripheral blood lymphocyte appearance in a case of I cell disease. In general, peripheral blood smears are performed to obtain information with regard to various morphological features as an aid in the diagnosis of infection or malignancy. This report presents a patient with I cell disease (inclusion cell disease), a fatal lysosomal storage disorder caused by a defect in an enzyme responsible for the transfer of mannose-6-phosphate ligands to precursor lysosomal enzymes. As a consequence, most lysosomal enzymes are transported outside the cell instead of being correctly targeted into the lysosomes, resulting in the storage of macromolecules in lysosomes. I cell disease, with its heterogeneous clinical presentation, can be diagnosed by the presence of intracellular vacuole-like inclusions in lymphocytes and fibroblasts, high serum lysosomal enzyme activities, and a defect of N-acetylglucosamine-1-phosphotransferase. This report describes the morphological aspects of peripheral lymphocytes in a blood smear of a patient, the first clue to the final diagnosis of I cell disease. The observed vacuole-like inclusions in lymphocytes of this patient were negative for periodic acid Schiff (PAS) and sudan black B staining, in contrast to earlier reports. ( info) |
12/147. Prenatal ultrasound diagnosis of Leroy I cell disease. Leroy I cell disease is a rare autosomal recessive disorder which progressively leads to death within the first decade of life. Invasive prenatal diagnosis is possible but is only undertaken in families who have previously had an affected child. We describe the antenatal ultrasound diagnosis of the disease in a case referred at 30 weeks' gestation for suspected polyhydramnios. ( info) |
13/147. Electronegative electroretinogram in mucolipidosis IV. OBJECTIVE: To demonstrate the progression of electroretinographic (ERG) findings in mucolipidosis IV. methods: Two patients with mucolipidosis IV were examined clinically and their condition was followed up for ophthalmic manifestations of the disease. Electroretinograms were performed on both patients, and conjunctival biopsy specimens were analyzed for characteristic ultrastructural inclusion bodies using light and electron microscopy. Genomic dna isolated from peripheral blood was screened for 2 major founder mutations in the ML4 gene using polymerase chain reaction and restriction fragment length polymorphism analyses. haplotypes were confirmed by automated sequencing of polymerase chain reaction products. RESULTS: In patient 1, an ERG obtained at 12 months of age showed mildly subnormal amplitude of rod-mediated and cone-mediated responses and significantly prolonged rod and cone b-wave implicit times. An ERG obtained when the patient was 6.6 years old disclosed marked progression with greater loss of b-wave than a-wave responses to rod-and-cone-mediated activity. Scotopic ERG at the highest intensity was electronegative in configuration. In patient 2, ERG showed minimal rod-mediated responses, severely subnormal cone-mediated responses, and prolonged cone b-wave implicit times. Again, electronegative configuration of the scotopic bright flash response indicated greater disturbance of b-wave generators. CONCLUSIONS: Novel ERG findings in 2 cases of mucolipidosis IV are reported with associated clinical courses, histopathologic abnormality, and genetic studies. In both cases ERGs demonstrate an electronegative configuration, suggesting that the primary retinal disturbance in mucolipidosis IV may occur at or proximal to the photoreceptor terminals. ( info) |
14/147. Novel missense mutations in the human lysosomal sialidase gene in sialidosis patients and prediction of structural alterations of mutant enzymes. Three novel missense mutations in the human lysosomal sialidase gene causing amino acid substitutions (P80L, W240R. and P316S) in the coding region were identified in two Japanese sialidosis patients. One patient with a severe, congenital form of type 2 sialidosis was a compound heterozygote for 239C-to-T (P80L) and 718T-to-C (W240R). The other patient with a mild juvenile-onset phenotype (type 1) was a homozygote for the base substitution of 946C-to-T (P316S). None of these mutant cDNA products showed enzymatic activity toward an artificial substrate when coexpressed in galactosialidosis fibroblastic cells together with protective protein/cathepsin a (PPCA). All mutants showed a reticular immunofluorescence distribution when coexpressed with the PPCA gene in COS-1 cells, suggesting that the gene products were retained in the endoplasmic reticulum/Golgi area or rapidly degraded in the lysosomes. Homology modeling of the structural changes introduced by the mutations predicted that the P80L and P316S transversions cause large conformational changes including the active site residues responsible for binding the sialic acid carboxylate group. The W240R substitution was deduced to influence the molecular surface structure of a limited region of the constructed models, which was also influenced by previously identified V217M and G243R transversions. ( info) |
15/147. Clinical variability in mucolipidosis III (pseudo-Hurler polydystrophy). Mucolipidosis III (MLIII) is caused by a deficiency of UDP-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine 1-phosphotransferase (phosphotransferase) activity, an enzyme responsible for the formation of the recognition marker on most lysosomal enzymes. The consequences of this defect are impairment of many lysosomal catabolic processes. A deficiency of phosphotransferase activity causes two phenotypically different diseases: mucolipidosis II and a rare form, mucolipidosis III (pseudo-Hurler polydystrophy). The purpose of this article is to report three patients with ML III, presenting quite different clinical courses: Patient 1 is a 13-year-old girl in whom the only symptoms of ML III were joint stiffness of the hands. patients 2 and 3 are sibs: a 5-year-old boy with a severe form of ML III and his 2-year-old sister, who is less affected than her brother at the same age. A comparison of biochemical results and the clinical picture of our patients with cases in the literature is presented. ( info) |
16/147. Mucolipidosis IV: novel mutation and diverse ultrastructural spectrum in the skin. Mucolipidosis IV, a severe neurologic and ophthalmologic progressive disorder has a clinical range of onset between early childhood and adolescence entailing clinically severe, moderate, and mild forms, all of them majorly affecting Ashkenazi Jewish patients in an autosomal-recessive fashion owing to mutations in the MCOLN1 gene which encodes a transmembrane protein called mucolipin 1. We report on one of two affected siblings, the older brother having died of ML IV at the age of 33 years, the younger recently at the age of 37 years. Biopsied skin disclosed several types of lysosomal residual bodies, membrane-bound vacuoles, avacuolar lamellar bodies resembling membraneous cytoplasmic bodies, and a diverse spectrum of lipopigments which include curvilinear and fingerprint profiles. Contrary to earlier reports, disease-specific lysosomal residual bodies could not be identified in circulating lymphocytes of our patient. mutation analysis revealed a homozygous novel mutation of a 34 bp deletion and 3 bp insertion in exon 2 of the MCOLN1 gene, perhaps the reason for this unusual clinical and morphological phenotype. ( info) |
17/147. A case of I-cell disease (mucolipidosis II) presenting with craniosynostosis. CASE REPORT: In this paper, a patient with mucolipidosis II (I-cell disease) is described. The initial findings were microcephaly and metopic craniosynostosis. He had coarse facial features and dysostosis multiplex. The first child in his family had died with severe bone pathology at 5 months of age. CONCLUSION: The case is presented to emphasize that craniosynostosis may be the first symptom in mucolipidosis II. ( info) |
18/147. Clinical variability of type II sialidosis by C808T mutation. Sialidosis (McKusick 256550) is an autosomal recessive disorder resulting from mutations in the NEU gene, located in 6p21.3, which leads to deficiency of alpha-N-acetyl neuraminidase (sialidase) activity, causing an accumulation of its substrates, oligosaccharides, in the lysosomes of various organs and tissues and an increased presence in urine and other organic fluids. We present a clinical report of three patients diagnosed for type II sialidosis. The first patient is a 12-year-old boy with the classic infantile form. His sister had a congenital form of sialidosis and died at 20 months of age. The third, nonrelated patient presented shortly after 1 year of age and had borderline cognitive delay at 9 years. All three patients were homozygous for the C808T mutation of the NEU gene. Their ancestors originated from a small area to the east of the city of Seville (spain), suggesting the existence of a Seville founder mutation. ( info) |
| I-cell disease (mucolipidosis II) is a rare metabolic disorder resulting from the deficiency of a specific lysosomal enzyme, N-acetylglucosamine-1-phosphotransferease. The disease presents as a mental and motor developmental delay with oral manifestations that include severe gingival hyperplasia usually seen before one year of age. The life expectancy of children with this condition is poor, with death usually occurring around the fifth year. A case report of a 3-year-old Pakistani male, with I-cell disease, is presented. The chief dental concerns of the parents were his swollen gums and delayed tooth eruption. Supportive treatment only was initiated. Differential diagnosis for severe gingival overgrowth in young patients should take account of this rare metabolic disorder in addition to hereditary and idiopathic fibromatosis and drug associated gingival overgrowth. ( info) |
20/147. Ophthalmological findings in a patient with mucolipidosis III (pseudo-hurler polydystrophy). A case report. Mucolipidosis III (Pseudo-Hurler Polydystrophy) is a rare autosomal recessively inherited Hurler-like disease. The ophthalmological findings in these patients include a triad of mild retinopathy, corneal clouding and hyperopic astigmatism. We present a patient with these ophthalmological characteristics. ( info) |