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Biomedical subjects

A Rajab

Publications and source records attributed to A Rajab.

At least 19 recordsLinked to original sources

Common autosomal recessive diseases in Oman derived from a hospital-based registry.

OBJECTIVES: The local frequencies of genetic disorders in Oman apart from hemoglobinopathies are largely unknown. The aim of the present study was to evaluate birth prevalence of commonly diagnosed autosomal recessive diseases and to estimate needs and priorities of genetic services. METHODS: Analysis of the years 1993-2002 using a hospital-based registry of genetic diseases was attempted. More than 3,000 records were reviewed. Only patients with definite diagnosis were included in the analysis. Genetically determined diseases occurring less frequently than 1 in 50,000 births are not included. RESULTS: A number of rare autosomal recessive diseases are found to have a prevalence at least 1 in 50,000 livebirths. CONCLUSIONS: The data suggest that genetic diseases are important as major contributors to perinatal and childhood mortality and morbidity. The need for preventive genetic service is essential for the health of the community in Oman. Autosomal recessive diseases were frequently concentrated in specific geographical areas, which can be explained by founder effect and genetic drift. However, the hospital-based registry may present incomplete information. Further prospective studies are needed to provide more detailed data.

Female↗

Spondyloepiphyseal dysplasia Omani type: a new recessive type of SED with progressive spinal involvement.

We report a large inbred kindred from Oman with a distinct type of spondyloepiphyseal dysplasia (SED). We evaluated eight individuals from two consanguineous sibships, one male and seven females between the ages of 2 and 22. The pedigrees strongly suggest autosomal recessive inheritance and both families are likely to be related through distant consanguineous loops. The clinical features include near to normal length at birth, short stature with final height of 110-130 cm, shortening of the upper segment due to severe progressive kyphoscoliosis, severe arthritic changes with joint dislocations, rhizomelic limbs, genu valgum, cubitus valgus, mild brachydactyly, camptodactyly, microdontia, and normal intelligence. Minor radiographic metaphyseal changes were found, but major manifestations were in the spine and the epiphyses. During the first year of life the vertebral bodies are of normal height but the endplates are irregular and intervertebral space is narrow. With age, the vertebral endplates become increasingly irregular, the intervertebral space diminishes further and individual vertebrae start to fuse resulting in a severe short trunk dwarfism with kyphoscoliosis. The epiphysis are small and precocious osteoarthropathy was observed involving small and large joints. The elbow, wrist, and hip joints were affected starting in infancy and showed restricted movement. Osteoarthropathy and spinal involvement resulted in physical handicap in early adulthood. Comparison of these patients with other skeletal dysplasias suggests that they represent a previously undescribed variant of SED.

Adolescent↗

Coeliac disease in Iranian type I diabetic patients.

BACKGROUND: The association between coeliac disease and type I diabetes mellitus has been evaluated in some previous studies, but its prevalence in Iranian diabetic patients remains unknown. AIM: To evaluate the prevalence of coeliac disease in patients with type I diabetes mellitus in Iran. PATIENTS: A total of 250 consecutive patients (102 male and 148 female) with type I diabetes mellitus. METHODS: Total serum immunoglobulin A level and immunoglobulin A endomysial antibody was measured for all patients. Endoscopy and biopsy of the duodenum were performed for immunoglobulin A endomysial antibody-positive patients and pathologic evaluation was done according to modified Marsh classification. RESULT: The mean age of the patients was 18.7 years (range: 2-55 years). Total serum immunoglobulin A was in the normal range for all patients. Immunoglobulin A endomysial antibody was positive in six (2.4%) patients (all of them were females; P = 0.04). Duodenal biopsy samples revealed grade I in two patients, grade II in three patients and grade IIIb in one patient (modified Marsh classification). Patients with coeliac disease and diabetes mellitus were older than patients with diabetes mellitus alone (mean age: 29.5 years versus 18.4 years; P < 0.001). There was a trend for longer duration of diabetes mellitus in coeliac patients than in patients without it (mean age: 17.3 years versus 12.5 years; P = 0.16). CONCLUSION: The prevalence of coeliac disease in Iranian patients with type I diabetes mellitus is relatively high (2.4%). Since almost half of the patients with coeliac disease are asymptomatic, all patients with type I diabetes mellitus should be screened for coeliac disease regardless of the presence of symptoms, at diagnosis of diabetes mellitus and with regular intervals in the follow up.

Adolescent↗

Serum antibodies to the major proteins found in cow's milk of Iranian patients with Type 1 diabetes mellitus.

The purpose of this study was to assess the humoral immune response to cow's milk proteins in Iranian children with Type 1 diabetes mellitus (T1DM). Eighty children aged 4-17 yr with T1DM from two centres in Iran (the Iranian Association of Diabetes in Tehran and Center for Diabetes Research in Hamedan), 37 apparently healthy siblings of diabetic patients (related controls), 82 apparently healthy age- and sex- matched controls (unrelated controls), and 32 patients aged 11-15 yr with auto-immune thyroiditis were examined for specific whole antibodies (Igs), IgG, and IgM to the major proteins found in cow's milk or to ovo-albumin by enzyme-linked immunosorbent assay (ELISA). A crude extract was made from 2.5% fat pasteurized cow's milk. This extract, together with individual commercial major proteins of cow's milk, was then used as antigen to evaluate the humoral immune response of the subjects to the individual proteins found in cow's milk or to cow's milk as a whole. A questionnaire on medical history, duration of exclusive and non-exclusive breast-feeding and daily intake of dairy products was completed before blood sampling. Diabetic children had significantly higher serum levels of Igs, IgG and IgM to the proteins found in cow's milk than unrelated healthy controls (p<0.001). Healthy siblings of diabetic patients, compared to unrelated controls, had significantly higher levels of serum Igs and IgG to cow's milk proteins (p<0.05 and p<0.01, respectively). Serum levels of Igs and IgG to the cow's milk proteins showed a significantly negative correlation with duration of non-exclusive breast-feeding but positive correlation with daily intake of dairy products. These correlations were stronger when calculated just within the T1DM group. In this group, serum levels of IgM to cow's milk proteins also showed a positive correlation with daily intake of dairy products. Though serum levels of IgG to casein were insignificantly higher in diabetic children than in healthy controls, there was a significant negative correlation between serum levels of IgG to casein and duration of non-exclusive breast-feeding. Again in the T1DM group, this correlation was stronger. There was no significant difference in serum levels of Igs, IgG or IgM to other major proteins of cow's milk or to ovo-albumin between groups. It was concluded that though high levels of Igs or IgG were found to cow's milk proteins, especially casein, it seems unrelated to the early introduction of cow's milk into an infant diet and the onset of T1DM in Iranian subjects.

Adolescent↗

Congenital generalized lipodystrophy, mental retardation, deafness, short stature, and slender bones: a newly recognized syndrome?

We present three patients with congenital generalized lipodystrophy, sensorineural deafness, low birth weight, short stature, delayed cognitive development, and progressive bone changes characterized by overtubulation and rarefaction of long bones with dense metaphyseal striations occurring in adolescence. Abnormalities of lipid and carbohydrate metabolism, hepatosplenomegaly, acanthosis nigricans, and hirsutism were not found. Comparison of the condition of these patients with known syndromic lipodystrophies suggests that they represent a previously unrecognized genetic disorder. The occurrence in sibs born to consanguineous parents and a third patient from the same tribal unit suggest autosomal recessive inheritance.

Adolescent↗

A novel form of pontocerebellar hypoplasia maps to chromosome 7q11-21.

OBJECTIVE: To describe a novel form of pontocerebellar hypoplasia (PCH) and map its genetic locus. BACKGROUND: PCH is a heterogeneous group of disorders that are characterized by abnormally small cerebellum and brainstem. Autosomal recessive inheritance has been implied in many cases, but no genetic loci have been mapped to date. METHODS: The authors studied a consanguineous family from the Sultanate of Oman with three siblings with a novel form of PCH. The authors performed clinical studies and linkage analysis of this pedigree. RESULTS: The clinical features of the affected children include developmental delay, progressive microcephaly with brachycephaly, seizures during the first year of life, hypotonia with hyperreflexia, short stature, and optic atrophy. Imaging studies showed a small pons and cerebellum, prominent sulci and lateral ventricles, and decreased cerebral white matter volume. A lack of dyskinesias distinguishes this pedigree from PCH type 2. Genetic studies of this family revealed evidence of significant linkage to chromosome 7q11-21 (maximum multipoint lod score 3.23). CONCLUSIONS: This pedigree represents a novel form of autosomal recessive PCH, which the authors propose to call cerebellar atrophy with progressive microcephaly (CLAM). This disorder maps to chromosome 7q11-21, and this locus was named CLAM. This report represents the first identification of a genetic locus for PCH.

Abnormalities, Multiple↗

Linkage of recessive Robinow syndrome to a 4 cM interval on chromosome 9q22.

Autosomal recessive Robinow syndrome is a form of mesomelic dwarfism with multiple rib and vertebral anomalies. Using autozygosity mapping we have identified a genetic locus (RBNW1) for this syndrome at chromosome 9q22 in seven consanguineous families from Oman. Our results indicate that the gene lies within a 4 cM region between markers D9S1836 and D9S1803 (maximum multipoint LOD score 12.3). In addition, we have analysed two non-Omani families with autosomal recessive Robinow and found no genetic heterogeneity.

Bone and Bones↗

Recessive Robinow syndrome, allelic to dominant brachydactyly type B, is caused by mutation of ROR2.

The autosomal recessive form of Robinow syndrome (RRS; MIM 268310) is a severe skeletal dysplasia with generalized limb bone shortening, segmental defects of the spine, brachydactyly and a dysmorphic facial appearance. We previously mapped the gene mutated in RRS to chromosome 9q22 (ref. 4), a region that overlaps the locus for autosomal dominant brachydactyly type B (refs 5,6). The recent identification of ROR2, encoding an orphan receptor tyrosine kinase, as the gene mutated in brachydactyly type B (BDB1; ref. 7) and the mesomelic dwarfing in mice homozygous for a lacZ and/or a neo insertion into Ror2 (refs 8,9) made this gene a candidate for RRS. Here we report homozygous missense mutations in both intracellular and extracellular domains of ROR2 in affected individuals from 3 unrelated consanguineous families, and a nonsense mutation that removes the tyrosine kinase domain and all subsequent 3' regions of the gene in 14 patients from 7 families from Oman. The nature of these mutations suggests that RRS is caused by loss of ROR2 activity. The identification of mutations in three distinct domains (containing Frizzled-like, kringle and tyrosine kinase motifs) indicates that these are all essential for ROR2 function.

Abnormalities, Multiple↗

Further delineation of the DOOR syndrome.

Two related sibships from an extended family have been observed with the features of the DOOR syndrome. These features included deafness, onychodystrophy, osteodystrophy, microcephaly, and global developmental retardation with progressive blindness. Seizures, which were associated with hypsarrhythmia, were frequent and difficult to control and ultimately were the cause of death in two patients. An MRI brain scan of case 1 showed a number of abnormalities including markedly reduced myelination. The urine organic acid analysis showed a ten-fold increase of 2-oxoglutarate. In one patient the placenta was noted to have multiple fluid filled cysts, which is a feature reported in other metabolic diseases. It is suggested that there may be genetic heterogeneity in the syndrome, and the presence of increased 2-oxoglutarate is associated with a more severe phenotype which is frequently lethal.

Abnormalities, Multiple↗

Analysis of the population structure in Oman.

Knowledge of a population structure can be a unique aid in planning genetic services. In order to facilitate the development of genetic services in the Sultanate of Oman, a tribal data base has been developed. The historic records of the beginning of the 19th century were used as the basis and were updated with contemporary information. The tribal data base includes tribal names, locations, and the main 185 major tribes and their subsections. Tribal data can be used for health care planning and the development of disease-specific genetic registers if the hospital records also include the tribal name. They may also provide a useful aid in genetic screening and disease prevention programmes, as when specific mutations are found in rare diseases, it is likely that these will be found to be exclusive to specific tribes, and laboratory testing will be greatly simplified. It is likely that similar data bases could be developed elsewhere in the Middle East and in the immigrant communities in Western Europe.

Journal Article↗

Recessive Robinow syndrome: with emphasis on endocrine functions.

We present the characteristic features of 14 children with the recessive form of Robinow syndrome and the growth hormone (GH) response to provocation with clonidine and the serum insulin-like growth factor-I (IGF-I) concentration in 12 of these children. The gonadotropin (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) response to gonadotropin-releasing hormone (GnRH) was evaluated in early pubertal and pubertal patients, and the testosterone response to human chorionic gonadotropin (HCG) was evaluated in males. Children with Robinow syndrome, born at full-term, were short at birth (length, 41.4+/-2.1 cm) and had markedly slow growth velocity (GV) during the first year (13.1+/-2.1 cm/yr); consequently, they were significantly short at the end of the first year of life (length, 54.4+/-2.9 cm). This intrauterine and early extrauterine growth delay reflected low growth potential. During childhood, the GV standard deviation score (GVSDS) remained low (-2.17+/-0.83). Despite the presence of empty sella in all of the patients, they had an adequate GH response to clonidine provocation (peak, 19.3+/-5.8 microg/L) and a normal serum IGF-I concentration (309+/-142 ng/mL) for their age. During childhood and early adolescence, boys with Robinow syndrome had low basal testosterone and a low testosterone response to HCG stimulation (3,000 IU/m2/d intramuscularly [IM] for 3 days). However, their basal and GnRH-stimulated FSH concentrations were normal. Two girls (Tanner II breast development) had a normal serum estradiol (E2) concentration but high LH and FSH responses to GnRH stimulation. This suggested either defective feedback of E2 on the hypothalamic-pituitary axis or hyporesponsiveness of the ovaries to gonadotropin. Four weeks of HCG therapy (2,500 IU/m2 IM twice weekly) in three boys with Robinow syndrome increased the penile length and testicular volume, denoting a significant Leydig cell response to prolonged HCG stimulation and the presence of functioning androgen receptors. It is suggested that HCG and/or testosterone therapy during infancy may improve the severe micropenis in these patients.

Abnormalities, Multiple↗

Neural tube defects and congenital hydrocephalus in the Sultanate of Oman.

A retrospective study was carried out in Oman to determine the incidence of neural tube defects (NTD) and congenital hydrocephalus (CH) and to identify any possible associations. National data retrieved from hospital records revealed the incidence of NTD in Oman to be comparatively low (1.25 per 1000), but the incidence of CH was much higher than that seen in Western Europe (0.44 per 1000) and was found to be associated with high rates of other congenital anomalies and neonatal death. There were no specific environmental factors associated with NTD and high environmental temperatures during the tropical desert summer (temperatures reach 48 degrees C) were excluded as a causative factor. In spina bifida families, later born children were more likely to be affected and there was also an association with increased maternal but not paternal age. Much higher consanguinity rates were noted in families with NTD and CH than in the general population.

Cohort Studies↗

Hirschsprung's disease in Oman.

The incidence of Hirschsprung's disease (HD) was studied retrospectively in Oman using hospital-based data. In Oman there is a single pediatric surgery unit where a register has been kept from 1989 to 1994, and because all cases are referred to this unit, a national survey could be carried out. There were 85 children with HD born between 1989 and 1994, and during the period there were 261,000 livebirths among Omani nationals. The population frequency in Oman is 1 in 3,070 (0.3/1,000). Eighty percent of cases presented in the first 6 months. The incidence in different regions and within different tribes of Oman was also studied. The highest frequency (1 in 1,800) is in the North Sharqiya region. There was not a significant seasonal influence in spite of the very high temperatures seen in the desert summer. The ratio of male to female cases was 2.9:1 overall, but less for longer-segment involvement. The consanguinity rate (first and second cousins) was 75%, which is higher than the level of consanguinity in the Omani population. Down's syndrome was observed in nine cases (11%), and a variety of other malformations were seen, including piebaldism, deafness, and HD in two sibships.

Abnormalities, Multiple↗