Identification and characterization of 30 novel pathogenic variations in 69 unrelated Indian patients with Mucolipidosis Type II and Type III.

Mucolipidosis (ML) (OMIM 607840 & 607838) is a rare autosomal recessive inherited disorder that occurs due to the deficiency of golgi enzyme uridine diphosphate (UDP)- N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) responsible for tagging mannose-6-phosphate for proper trafficking of lysosomal enzymes to lysosomes. Variants in GlcNAc-phosphotransferase (GNPTAB (α, ß subunits) and GNPTG (γ subunits) are known to result in impaired targeting of lysosomal enzymes leading to Mucolipidosis (ML) Type II or Type III. We analyzed 69 Indian families of MLII/III for clinical features and molecular spectrum and performed in silico analysis for novel variants. We identified 38 pathogenic variants in GNPTAB and 5 pathogenic variants in GNPTG genes including missense, frame shift, deletion, duplication and splice site variations. A total of 26 novel variants were identified in GNPTAB and 4 in GNPTG gene. In silico studies using mutation prediction software like SIFT, Polyphen2 and protein structure analysis further confirmed the pathogenic nature of the novel sequence variants detected in our study. Except for a common variant c.3503_3504delTC in early onset MLII, we could not establish any other significant genotype and phenotype correlation. This is one of the largest studies reported till date on Mucolipidosis II/III in order to identify mutation spectrum and any recurrent mutations specific to the Indian ethnic population. The mutational spectrum information in Indian patients will be useful in better genetic counselling, carrier detection and prenatal diagnosis for patients with ML II/III.

Identification of compound heterozygous mutations in GNPTG in three siblings of a Chinese family with mucolipidosis type III gamma.

Mucolipidosis III gamma is an autosomal recessive disorder with defective phosphorylation and trafficking of lysosomal enzymes. In a Chinese family with three siblings, linkage analysis revealed positive linkage of the family to GNPTG. Direct DNA sequence analysis identified two novel compound heterozygous mutations, c.471delC in exon 7 and IVS4-1G>C, in three patients. The two mutations cause frameshift and abnormal splicing, respectively, and represent the first series of GNPTG mutations in the Chinese population.

Microvillous inclusion disease: a clinicopathologic study of 17 cases from the UK.

BACKGROUND: Microvillous inclusion disease (MVID) is a rare congenital disease producing intractable secretory diarrhea in early infancy. It is characterized by diffuse intestinal villous atrophy with no inflammatory reaction. Ultrastructural identification of apical microvillous inclusions in the surface enterocytes is diagnostic. However, there is difficulty in the diagnosis of MVID due to the existence of variants (e.g., microvillous dystrophy), possible disease resolution, and tissue orientation for electron microscopy (EM). The authors analyzed materials from 4 patients with MVID from a single institution. The morphologic features, distribution of lesions, biomarkers, and complementary ultrastructural characteristics were studied. DESIGN: Materials of MVID cases were collected from 6 different hospitals in the United Kingdom between 1990 and 2008. Epidemiological data, including age range, median, mode, sex ratios, and follow-up, were retrieved. All intestinal biopsy specimens were analyzed histologically, histochemically (for PAS, n = 17), immunohistochemically (for CD10, n = 2 and polyclonal CEA, n = 4), and ultrastructurally (n = 9). RESULTS: Ultrastructurally, apical microvillous inclusions in surface enterocytes in duodenal biopsies were identified in all cases, while 1 case had variant morphology (microvillous dystrophy and very occasionally atypical microvillous inclusions). Tissue orientation for EM was supportive for identification of inclusions in apical enterocytes. Morphologically, a bubbly vacuolated appearance of the apical cytoplasm with extensive or patchy absence of the brush border with occasional cytoplasm inclusions was observed in the enterocytes. Some of these changes vaguely resembled gastric mucin cell metaplasia. Architecturally, villous blunting with either crypt hypoplasia or hyperplasia and absence of inflammation were common findings. The epithelial changes were also found in colon biopsies. PAS, CD10, and p-CEA showed a bright apical cytoplasmic blush/staining, which correlated ultrastructurally with apical granules with inclusions of variable electron density in all cases. These stains also highlighted the targetoid inclusions. CONCLUSION: Besides electron microscopy identification of inclusions, the light microscopic morphological features together with the biomarker studies highlighting the apical cytoplasmic blush are quite unique and diagnostic of MVID. Furthermore, it is the opinion of the authors that a diagnosis of MVID can be made without electron microscopy.

The frequency of mucolipidosis type IV in the Ashkenazi Jewish population and the identification of 3 novel MCOLN1 mutations.

Mucolipidosis type IV (MLIV) is a neurodegenerative lysosomal storage disorder that occurs in an increased frequency in the Ashkenazi Jewish (AJ) population. The frequency of the disease in this population has been established by the testing of 66,749 AJ subjects in the Dor Yeshorim program, a unique premarital population-screening program designed for the Orthodox Jewish community. A carrier rate of 0.0104 (95% C.I 0.0097-0.011) was found. The distribution of the 2 AJ founder mutations, namely, c.416-2A>G and c.1_788del, was determined to be 78.15% and 21.85%, respectively. Three novel mutations were identified in non-Jewish MLIV patients, a missense mutation c.1207C>T, p.Arg403Cys; a 2bp deletion, c.302_303delTC; and a nonsense, c.235C>T, Gln79X.

Rapid detection of the two common mutations in Ashkenazi Jewish patients with mucolipidosis type IV.

Among Ashkenazi Jewish individuals with mucolipidosis IV (ML IV), two mutations in the ML IV gene, IVS3-1A --> G and delEX1-EX7, account for more than 95% of disease alleles. The reported method of genotyping for the delEX1-EX7 mutation involves a cumbersome multistep procedure. In the present study, a new simplified one-step procedure is described that detects this mutation in both patients and carriers. An improved procedure is also described for detection of the IVS3-1A --> G mutation. Using these improved procedures, we have characterized the ML IV mutant alleles in 27 patients and 95 of their relatives from 22 families, and in 123 unrelated and unaffected Ashkenazi Jewish controls. Of the 27 ML IV patients, 16 patients (59.3%) were found to be homozygous for the IVS3-1A --> G mutation and 1 patient (3.7%) homozygous for the delEX1-EX7 mutation. Additionally, 9 patients (33.3%) were compound heterozygotes for IVS3-1A --> G/delEX1-EX7. Among the 123 Ashkenazi Jewish controls, two individuals were identified as heteroallelic with one IVS3-1A --> G mutation (carrier frequency: approximately 1 in 61); none showed the delEX1-EX7 mutation. The modifications described here provide a more facile means of genotyping patients and carriers and expand the possibilities for screening at-risk populations.

Mucolipidosis type IV: novel MCOLN1 mutations in Jewish and non-Jewish patients and the frequency of the disease in the Ashkenazi Jewish population.

The gene MCOLN1 is mutated in Mucolipidosis type IV (MLIV), a neurodegenerative, recessive, lysosomal storage disorder. The disease is found in relatively high frequency among Ashkenazi Jews due to two founder mutations that comprise 95% of the MLIV alleles in this population [Bargal et al., 2000]. In this report we complete the mutation analysis of Jewish and non-Jewish MLIV patients whose DNA were available to us. Four novel mutations were identified in the MCOLN1 gene of severely affected patients: two missense, T232P and F465L; a nonsense, R322X; and an 11-bp insertion in exon 12. The nonsense mutation (R322X) was identified in two unrelated patients with different haplotypes in the MCOLN1 chromosomal region, indicating a mutation hotspot in this CpG site. An in-frame deletion (F408del) was identified in a patient with unusual mild psychomotor retardation. The frequency of MLIV in the general Jewish Ashkenazi population was estimated in a sample of 2,000 anonymous, unrelated individuals assayed for the two founder mutations. This analysis indicated a heterozygotes frequency of about 1/100. A preferred nucleotide numbering system for MCOLN1 mutations is presented and the issue of a screening program for the detection of high-risk families in the Jewish Ashkenazi population is discussed.

The frequency of lysosomal storage diseases in The Netherlands.

We have calculated the relative frequency and the birth prevalence of lysosomal storage diseases (LSDs) in The Netherlands based on all 963 enzymatically confirmed cases diagnosed during the period 1970-1996. The combined birth prevalence for all LSDs is 14 per 100,000 live births. Glycogenosis type II is the most frequent LSD with a birth prevalence of 2.0 per 100,000 live births, representing 17% of all diagnosed cases. Within the group of lipidoses, metachromatic leukodystrophy (MLD) is the most frequent LSD. MLD was diagnosed in 24% of lipidoses and the calculated birth prevalence was 1.42 per 100,000 for all types combined. Krabbe disease, diagnosed in 17% of cases, also belongs to the more frequent lipid storage diseases in The Netherlands with a birth prevalence of 1.35 per 100,000. The birth prevalence of Gaucher disease, commonly regarded as the most frequent lipid storage disease is 1.16 per 100,000 for all types combined. The combined birth prevalence for all lipid storage diseases is 6.2 per 100,000 live births. Within the group of mucopolysaccharidoses (MPSs), MPS I has the highest calculated birth prevalence of 1.19 per 100,000 (25% of all cases of MPS diagnosed), which is slightly more frequent than MPS IIIA with an estimated birth prevalence of 1.16 per 100,000. As a group, MPS III comprises 47% of all MPS cases diagnosed and the combined birth prevalence is 1.89 per 100,000 live births. The birth prevalence of MPS II is 0.67 per 100,000 (1.30 per 100,000 male live births). All other MPSs are rare. The combined birth prevalence for all MPSs is 4.5 per 100,000 live births. Mucolipidoses and oligosaccharidoses are very rare with birth prevalences between 0.04 and 0.20 for individual diseases. Only 49 cases were diagnosed between 1970 and 1996. Their combined birth prevalence is 1.0 per 100,000 live births.

[Mucolipidosis II (I cell disease). First case report in the Czech Republic and prenatal diagnosis in a family]. / Mukolipidóza II (I cell disease). Popis prvého prípadu v Ceské republice a prenatální diagnóza v rodine.

The authors describe the first case of mucolipidosis II in the Czech Republic. The cause of this autosomal recessive hereditary disease is deficient synthesis of mannoso-6-phosphate ligand on precursors of lysosomal enzymes which normally make their transport into the lysosomal system possible. The diagnosis was proved by the presence of typical lysosomal cumulation in bioptic specimens and extremely elevated activity of lysosomal enzymes in the patient's serum caused by their non-regulated secretion and subsequent intracellular depletion. During the second pregnancy in the family prenatal diagnosis was made. A normal range of lysosomal enzyme activities in the supernatant of the amniotic fluid and in cultivated chorionic villi along with normal results of ultrastructural examination of the chorionic villus indicated the development of an intact foetus.

Lysosomal storage diseases in Greece.

Over the last 13 years 2745 patients from all over Greece suspected to have a lysosomal storage disorder were referred to the Institute of Child Health. 1581 of those were suspected of having a mucopolysaccharidosis (MPS). 94 cases (3.42% of the total referrals) were positive: 36 patients with MPS, 6 with mucolipidosis (1 type I, 1 type II and 4 type III) and 3 with mannosidosis. Sanfilippo B was not only the most frequent type III MPS but also the most frequent MPS identified in our study. Sphingolipidoses and other lysosomal disorders were diagnosed in 47 cases and non-lysosomal disorders in 19 cases. In our experience Gaucher disease, Sanfilippo B and Hunter syndrome are the most frequent lysosomal disorders in Greece accounting for 23.4%, 17.0% and 7.6% respectively of all diagnosed cases. 13% of the patients originated from Thessaly including 5/16 Sanfilippo B, 2/3 Morquio B, 2/3 Maroteaux-Lamy, 2/6 Metachromatic leukodystrophy and 2/12 Gaucher type 1.

Mucolipidosis type IV: a mild form with late onset.

A 16-year-old girl is presented with mild clinical manifestations and late onset of mucolipidosis type IV (MLIV). The patient, an Ashkenazi Jew, has had minor motor difficulties and mild psychological disturbances since early childhood. Her vision began deteriorating at 12 years of age, due to bilateral corneal opacities and retinal degeneration. At present she attends a regular high school, although she is slow and scholastic achievements are lower than average. Electron microscopic examination and biochemical studies were typical for MLIV, namely, abnormal ganglioside retention and typical pattern of phospholipids accumulation. This very mild presentation of MLIV suggests a broader spectrum of heterogeneity of this disorder and raises the possibility that MLIV, at least among Ashkenazi Jews, might be more frequent than estimated hitherto, due to undiagnosed mild patients.

[Skeletal changes in 2 German children with aspartylglycosaminuria]. / Skelettveränderungen bei zwei deutschen Kindern mit Aspartylglucosaminurie.

Two sibs showed delayed speech development, motor retardation and coarsening of their features during their second year of life. Radiological examination of the skeleton showed changes of dysostosis multiplex. Both children showed storage vacuoles in peripheral lymphocytes and a typical oligosaccharide-banded pattern on urinary chromatography. The diagnosis of aspartylglycosaminuria was confirmed by the demonstration of reduced activity of the enzyme aspartylglucosaminidase in leukocytes and in cultured fibroblasts. Treatment of this autosomal recessive inherited glycoprotein storage disease is not possible. Early recognition is important for genetic counselling of the family. This paper describes the first recognised cases in German literature.

[A cluster of mucolipidosis III in a village of Calabria]. / Un "cluster" di Mucolipidosi III in un paesino della Calabria.

The authors report three cases of patients with clinical findings of Mucolipidosis III. Contractures of joint, stiffness of the hands short stature and coarse faces were observed. The lisosomal enzyme activities in serum and leucocytes were measured. The same activities were measured in extracts and by means of cultured skin fibroblast cells. These data are concordant with literature. These patients come from a Calabrian village of 100 habitants 90% of whom have the same surname.

Farber's disease (disseminated lipogranulomatosis): the first case reported in Japan.

We report the first case in Japan, i.e., the first case among oriental subject of Farber's disease. This is a rare disorder of lipid metabolism in infancy subsequent to a genetically-determined defect in ceramide degradation. Main features are characterized clinically by hoarseness, joint swelling, subcutaneous nodules and retarded psychomotor development. Lipid analysis and pathological investigation on the material obtained from a subcutaneous nodule confirmed clearly the presence of ceramide and intracytoplasmic inclusion bodies characteristic for Farber's disease. In this case, we experienced also corneal opacity and striking abnormalities in electroencephalogram, which have apparently not been noticed in the 17 cases hitherto reported.