Homozygous AMN mutation in hereditary selective intestinal malabsorption of vitamin B12 in Jordan.

OBJECTIVE: Juvenile megaloblastic anemia is a rare and often hereditary disorder of cobalamin absorption, transport or intracellular metabolism. Several syndromes present with megaloblastic anemia such as congenital megaloblastic anemia due to intrinsic factor defect and juvenile megaloblastic anemia with proteinuria due to defects in the cubilin or the amnionless protein. METHODS: We identified a large kindred with juvenile megaloblastic anemia. Four genes, GIF, CUBN, TCN1, and TCN2, was previously excluded from being responsible for the syndrome of this family who was discovered in Irbid, Jordan, during the year 1999. At that time, the amnionless (AMN) gene was not yet known to implicate in megaloblastic anemia. In this study, we screened the AMN for mutations in the Ohio State University, Iowa, United States of America. In addition, follow-up testing was carried out in the University of Iowa in 2004. RESULTS: We identified a homozygous splice site mutation in the patients. This mutation was previously detected in families from Turkey and Tunisia. It is suspected to be a founder mutation of Middle Eastern origin. CONCLUSION: Molecular testing for this specific mutation in cases of Middle Eastern origin is a valuable tool for presymptomatic diagnosis, carrier identification and perhaps prenatal diagnosis.

Familial Mediterranean fever mutation frequencies and carrier rates among a mixed Arabic population.

OBJECTIVE: Familial Mediterranean Fever (FMF) is an autoinflammatory periodic disorder characterized by febrile and painful attacks due to inflammation involving the serosal membranes. The gene implicated in this disorder, MEFV, has been cloned and mutations in its coding regions have been identified. We aimed at identifying the frequency of MEFV mutations and carrier frequency in a mixed Arabic population. METHODS: We identified 29 probands from 29 unrelated sibships segregating the disorder and representing the affected individual cohort. We screened 200 anonymous deoxyribonucleic acid (DNA) samples, representing a healthy adult cohort, for the mutations found to be common in the affected individual cohort. We also, screened anonymous DNA samples from 4 Arabic countries, namely, Egypt (231), Syria (225), Iraq (176) and the Kingdom of Saudi Arabia (107) thus enlarging our healthy adult cohort. The study was carried out between 1999 and 2002 at Jordan University of Science and Technology, Irbid and the University of Jordan, Amman, Jordan. RESULTS: Out of the 58 alleles of the 29 probands, only 31 mutations were identified and M694V and V726A are the most common. The mutation E148Q was the most common among the healthy adult cohort, but was not present in affected individuals. The collective mutant allele frequency "q" was 0.101. The expected carrier rate was 18.1% (one in 5.5) while the observed carrier rate was 18.4% (one in 5.4). CONCLUSION: E148Q has reduced penetrance and thus, a proportion of the individuals genetically affected with FMF remain asymptomatic. M694I and M680I are more prevalent in the affected individuals cohort, which points to their higher penetrance. The overall carrier rate is one in 5, but the selective heterozygote advantage could not be demonstrated in this study due to the relatively small sample size.

Linkage analysis of a large inbred family with congenital megaloblastic anemia.

OBJECTIVE: Megaloblastic anemia during infancy and early childhood often reflects a hereditary disorder of cobalamin's absorption, transport, or intracellular metabolism. There are 3 well defined autosomal recessive syndromes manifesting with megaloblastic anemia due to defects in cobalamin absorption or transport, namely congenital pernicious anemia, Imerslund-Grasbeck syndrome and Transcobalamin II deficiency. The genes responsible for the 3 disorders are gene intrinsic factor (GIF), MGA1 and TCN2, as well as the gene for Transcobalamin I, TCN1 are mapped or cloned, or both. METHODS: We describe the clinical picture of 7 patients from 3 sibships, belong to one large inbred family who presented with megaloblastic anemia during infancy. The mode of inheritance follows an autosomal recessive pattern and the syndrome was completely reversed by parentral vitamin B12 therapy. The ascertainment of the family was carried out in 1998 in the Princess Rhama Children's Hospital, which is affiliated with Jordan University of Science and Technology, Jordan. We performed linkage analysis in this family for genes or regions involved in the above mentioned disorders. RESULTS: The genes implicated in the etiology of the previously mentioned disorders were excluded from being responsible for the disorder in this family. CONCLUSION: The exclusion of the involvement of GIF, MGA1, TCN1 and TCN2 in this family suggests that another gene and its product, involved in cobalamin absorption or transport, remains to be identified. A genome-wide search of the gene implicated in this family may give some insight on that gene, and its function.

Zinc in normal and pathological human prostate gland.

OBJECTIVE: This study is conducted to detect quantitatively zinc in the nuclei and cytoplasm of epithelial cells of the prostate from normal, acute prostatitis, benign prostatic hyperplasia and adenocarcinoma. METHODS: Prostatic tissues from normal, acute prostatitis, benign prostatic hyperplasia and adenocarcinoma were obtained from patients and processed for zinc detection using x-ray microanalysis technique. The samples were collected over a period of 2-3 years and were processed at Jordan University of Science and Technology, Irbid, Jordan. RESULTS: Zinc was increased and decreased both in the nuclei and the cytoplasm of the glandular epithelium of benign prostatic hyperplasia and adenocarcinoma of the prostate. Although zinc was increased in the nuclei and cytoplasm of epithelial cells of acute prostatitis, it was not significant. CONCLUSION: These findings might be caused by factors affecting the zinc metabolic pathway directly or through the zinc bound protein metallothionein. In addition, these findings could be used in diagnosing different prostatic pathological conditions and advancing prostatic tumors and those with similar histopathological profiles.

Nuclear zinc in liver of cadmium and zinc treated rats.

X-ray microanalysis was performed to detect quantitatively, the variation of the nuclear zinc in the liver cells of rats. The nuclear zinc concentration showed statistical decrease and increase in response to cadmium and zinc treatments, respectively. The results suggest that the liver responds differently to cadmium and zinc treatments. The difference in response to either treatment may reflect different mechanisms of zinc transport and metabolism in the liver. The difference in binding affinity of metallothionein (MT) may suggest the involvement of Mt in the metabolism and transport of zinc, an effect, which may be modified by treatment.