Overview on the first human cytogenetic research in Sudan

The present study is the first human cytogenetic project in Sudan which was titled: Cytogenetic and FISH analyses in Sudanese patients with dysmorphic features, ambiguous genitalia, and infertility. The aim of the present study was not only to characterize the genetic alterations in patients with dysmorphic features, ambiguous genitalia and/or infertility among Sudanese population, but also to attract the medical community attention to the importance of human cytogenetics in clinical genetics practice, and also to facilitate the introduction and clinical application of such valuable service in Sudan. In this study chromosomal G-banding and fluorescence in situ hybridisation [FISH] analysis were performed on 44 Sudanese patients, 29 females, 14 males, and one patient with unassigned sex. Patients age ranging between 17 days-39 years [mean 18 years]. Of the 44 patients, 20 had ambiguous genitalia, 8 dysmorphic features, 11 have puberty and/or fertility complains, and 5 were healthy individual [parents of 3 patients with dysmorphic features]. Cytogenetic analysis of 20 patients complaining of ambiguous genitalia [13 females and 6 males, and one case with unassigned sex] showed that 8 has karyotypes different from their assigned sex and the other cases showed karyotypes consistent with Edward syndrome [47,XX,+18] [case 7], and a case with 45yXdel[X][pll] [case 11] respectively, when using FISH the 45,Xdel[X][pl 1] case showed translocation of the SRY [sex-determining region Y], gene to the active X chromosome. For the 8 patients of dysmorphic features; five showed karyotypes consistent with Down syndrome, of which one showed Robertsonian translocation, with both FISH and ordinary G-banding, and the other three showed normal karyotypes. All the parents showed normal karyotypes. Among the infertility cases all showed normal karyotypes, except for two which showed karyotypes consistent with Turner syndrome and one which showed a male karyotype although the case was raised as a female; ultrasound showed a mass in the position of prostate. The study, the ever first one in Sudan, assured the importance, the possibility, and the need for cytogenetic and FISH analysis in diagnosis, management and genetic counseling of genetic diseases caused by constitutional chromosomal changes among Sudanese patients

Cancer cytogenetics: a review

According to the national registry at the Ministry of Health, cancer is the second cause of death in Sudan. Worldwide, one in three persons develops cancer at some time during their lives, and one in four dies from this disease. Today, it is widely accepted that cancer arises through a multistep accumulation of inherited and/or acquired mutations of the genetic material leading to clonal selection of neoplastically transformed cells showing unrestrained proliferation and the ability to infiltrate locally and to set up distant metastases. Many of the genetic alterations acquired by neoplastic cells are visible as chromosomal aberrations which are clearly nonrandom in distribution and sometimes occur in highly specific pattern. These chromosome aberrations are therefore highly informative with regard to the pathogenetic events of carcinogenesis, and their identification and classification have proved to be of great diagnostic and prognostic value for patients with malignant disorders. Cancer cytogenetic was recently introduced in Sudan, however it is not yet full valued and thus used by Sudanese physician in the diagnosis and management of patients with hematological malignancies, bone and soft tissue tumors. The present article reviews the importance of cancer cytogenetic and its role in clinical practice

Molecular diagnosis of spinal muscular atrophy

Spinal muscular atrophy [SMA] is a common, often fatal, autosomal recessive neurodegenerative disease that leads to progressive paralysis, atrophy, and wasting of voluntary muscles due to degeneration of the anterior horn cells of the spinal cord. Due to increased consanguinity marriage in Muslims countries, the prevalence of SMA cases is much higher than in Europe and North America population. SMA has been linked to mutation in the Survival Motor Neuron gene [SMN]. The gene mapped to chromosome 5ql3, and present in two homologous copies [SMN1 and SMN2]. Homozygous deletion of exons 7 and 8 of SMN1 are responsible for SMA in 94% of patients, and most disease carriers have only one copy. Although, molecular analysis of the biallelic exon 7 of SMN1 deletion became standard and reliable diagnostic test in cases of SMA, recent use of others quantitative tests that based on "real-time PCR" has also enhanced the diagnostic potential by increasing the detection rate especially in cases caused by point mutation of SMN1 gene. In the absence of effective treatment molecular screening for carrier detection and prenatal prediction of affected fetus are acceptable preventive options, especially for the severe forms of the disease. The present article review and discuss the use of molecular techniques in clinical diagnosis, carrier detection, genetic counseling and prenatal screening of patients and families with SMAs