HIBM Research Group

Sherman Oaks, CA, United States

HIBM Research Group

Sherman Oaks, CA, United States
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Valles-Ayoub Y.,HIBM Research Group | Esfandiarifard S.,HIBM Research Group | No D.,HIBM Research Group | No D.,Los Angeles Mission College | And 6 more authors.
Genetic Testing and Molecular Biomarkers | Year: 2011

Wolman disease (WD) is a rare inherited condition caused by lysosomal acid lipase (LAL) deficiency first described in Iranian-Jewish (IJ) children. Newborns with WD are healthy and active, but soon the infant develops symptoms of severe malnutrition in the first few months of life, and often dies before the age of 1 year. Harmful amounts of lipids accumulate in the spleen, liver, bone marrow, intestine, adrenal glands, and lymph nodes. Although worldwide incidence is estimated at 1/350,000 newborns, WD occurs at higher than expected frequency in the IJ community of the Los Angeles area. As a validation study, we analyzed 162 DNA specimens of IJ origin by automated sequencing. For LIPA p.G87V (ggc>gtc, alternative numbering p.G66V), a heterozygous frequency of 5/162 (3.086%) was discovered. Thus, we estimate that as high as 1 in 4200 newborns of IJ couples may be at risk. Additional studies are required to confirm and further validate the higher frequencies seen in our sample pool, and to determine if people of IJ and even possibly Middle Eastern descent are at a higher risk for WD. © Copyright 2011, Mary Ann Liebert, Inc.

Khademian H.,HIBM Research Group | Mehravar E.,Sangesar Charity Organization for HIBM | Urtizberea J.A.,Hopital Marin | Sagoo S.,HIBM Research Group | And 7 more authors.
Clinical Genetics | Year: 2013

GNE myopathy or hereditary inclusion body myopathy (HIBM) is an ultra-rare severely disabling autosomal recessive adult onset muscle disease which affects roughly one to three individuals per million worldwide. Genetically, HIBM is caused by mutations in the glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase gene (GNE), resulting in diminished enzyme function and reduced sialic acid biosynthesis. A founder variant GNE p.M712T was first described in patients of Iranian and Middle-Eastern descent living outside of Iran. Asymptomatic heterozygote or carrier frequency has been reported as high as 1 in 11 within the Persian-Jewish community residing in Los Angeles, CA. To investigate the prevalence of the p.M712T variant in Iran, we studied 792 samples collected from random individuals in Sangesar (Mahdishahr) in Northern Iran. DNA samples were obtained by buccal swab, and genotyping was performed by melting curve analysis. The results included 31 of 792 (3.91%) heterozygous carriers and 5 (0.31%) homozygotes for GNE p.M712T. All five homozygous individuals, age 30-64years, were already symptomatic at the start of the study. Our findings suggest that the prevalence of GNE p.M712T is higher in the Sangesar population, comprised mostly of Muslim and Bahai descendants, compared with the general world population. Additional HIBM distribution studies are warranted within various subpopulations of Iran. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Valles-Ayoub Y.,HIBM Research Group | Esfandiarifard S.,HIBM Research Group | Sinai P.,HIBM Research Group | Carbajo R.,HIBM Research Group | And 9 more authors.
Genetic Testing and Molecular Biomarkers | Year: 2012

Hereditary inclusion body myopathy (HIBM) is a young-adult onset autosomal recessive disorder caused by a hypomorphic rate limiting enzyme of sialic acid biosynthesis. The enzyme is UDP-N-acetylglucosamine 2-epimerase/N- acetylmannosamine kinase, and is encoded by the GNE gene. HIBM causes slowly progressive muscle weakness and atrophy. Patients are typically diagnosed at 20-30 years of age, and most patients are incapacitated and wheelchair-confined by 30-50 years of age. Some sialic acid containing glycoproteins, including neural cell adhesion molecule (NCAM), are hyposialylated in HIBM muscle biopsy samples. We developed a method to allow detection of serum NCAM sialylation using Western blot, and tested serum samples from several patients and a HIBM mouse model. Preliminary results showed a clear difference in polysialylated and hyposialylated forms of NCAM extracted from serum, and showed NCAM is hyposialylated in HIBM serum samples. This initial finding may prove useful in reducing the need for serial muscle biopsies in HIBM treatment trials. Additional studies are underway to further validate this finding and to evaluate the specificity, reliability, and robustness of this potential serum biomarker for HIBM. © 2012 Mary Ann Liebert, Inc.

Kakani S.,Human Genome Research Institutes | Yardeni T.,Human Genome Research Institutes | Yardeni T.,Tel Aviv University | Poling J.,Human Genome Research Institutes | And 16 more authors.
American Journal of Pathology | Year: 2012

Pathological glomerular hyposialylation has been implicated in certain unexplained glomerulopathies, including minimal change nephrosis, membranous glomerulonephritis, and IgA nephropathy. We studied our previously established mouse model carrying a homozygous mutation in the key enzyme of sialic acid biosynthesis, N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase. Mutant mice died before postnatal day 3 (P3) from severe glomerulopathy with podocyte effacement and segmental glomerular basement membrane splitting due to hyposialylation. Administration of the sialic acid precursor N-acetylmannosamine (ManNAc) led to improved sialylation and survival of mutant pups beyond P3. We determined the onset of the glomerulopathy in the embryonic stage. A lectin panel, distinguishing normally sialylated from hyposialylated glycans, used WGA, SNA, PNA, Jacalin, HPA, and VVA, indicating glomerular hyposialylation of predominantly O-linked glycoproteins in mutant mice. The glomerular glycoproteins nephrin and podocalyxin were hyposialylated in this unique murine model. ManNAc treatment appeared to ameliorate the hyposialylation status of mutant mice, indicated by a lectin histochemistry pattern similar to that of wild-type mice, with improved sialylation of both nephrin and podocalyxin, as well as reduced albuminuria compared with untreated mutant mice. These findings suggest application of our lectin panel for categorizing human kidney specimens based on glomerular sialylation status. Moreover, the partial restoration of glomerular architecture in ManNAc-treated mice highlights ManNAc as a potential treatment for humans affected with disorders of glomerular hyposialylation. © 2012 American Society for Investigative Pathology.

No D.,HIBM Research Group | Valles-Ayoub Y.,HIBM Research Group | Carbajo R.,HIBM Research Group | Khokher Z.,HIBM Research Group | And 7 more authors.
Genetic Testing and Molecular Biomarkers | Year: 2013

Hereditary Inclusion Body Myopathy (HIBM, IBM2, MIM:600737) is an autosomal recessive adult onset progressive muscle wasting disorder. It is associated with the degeneration of distal and proximal muscles, while often sparing the quadriceps. The bifunctional enzyme UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE/MNK), encoded by the GNE gene, catalyzes the first two committed, rate-limiting steps in the biosynthesis of N-acetylneunaminic acid (sialic acid). Affected individuals have been identified with mutations in the GNE gene. In the present study, the GNE coding region of 136 symptomatic patients were sequenced. A total of 41 patients were found to have GNE mutations. Eight novel mutations were discovered among seven patients. Of the eight novel mutations, seven were missense (p.I150V, p.Y186C, p.M265T, p.V315T, p.N317D, p.G669R, and p.S699L) and one was nonsense (p.W495X), all of which span the epimerase, kinase, and allosteric domains of GNE. In one patient, one novel mutation was found in the allosteric region and kinase domain of the GNE gene. Mutations in the allosteric region lead to a different disease, sialuria; however, this particular mutation has not been described in patients with sialuria. The pathological significance of this variation with GNE function remains unknown and further studies are needed to identify its connection with HIBM. These findings further expand the clinical and genetic spectrum of HIBM. © Copyright 2013, Mary Ann Liebert, Inc.

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