Susceptible and Prognostic Genetic Factors Associated with Diabetic Peripheral Neuropathy: A Comprehensive Literature Review.

Type 2 diabetes mellitus (T2D) is a disorder of glucose metabolism. It is a complex process involving the regulation of insulin secretion, insulin sensitivity, gluconeogenesis, and glucose uptake at the cellular level. Diabetic peripheral neuropathy (DPN) is one of the debilitating complications that is present in approximately 50% of diabetic patients. It is the primary cause of diabetes-related hospital admissions and nontraumatic foot amputations. The pathogenesis of diabetic neuropathy is a complex process that involves hyperglycemia-induced oxidative stress and altered polyol metabolism that changes the nerve microvasculature, altered growth factor support, and deregulated lipid metabolism. Recent literature has reported that there are several heterogeneous groups of susceptible genetic loci which clearly contribute to the development of DPN. Several studies have reported that some patients with prediabetes develop neuropathic complications, whereas others demonstrated little evidence of neuropathy even after long-standing diabetes. There is emerging evidence that genetic factors may contribute to the development of DPN. This paper aims to provide an up-to-date review of the susceptible and prognostic genetic factors associated with DPN. An extensive survey of the scientific literature published in PubMed using the search terms "Diabetic peripheral neuropathy/genetics" and "genome-wide association study" was carried out, and the most recent and relevant literature were included in this review.

A child with multiple congenital anomalies due to partial trisomy 7q22.1 → qter resulting from a maternally inherited balanced translocation: a case report and review of literature.

BACKGROUND: Parental balanced reciprocal translocations can result in partial aneuploidies in the offspring due to unbalanced meiotic segregation during gametogenesis. Herein, we report the phenotypic and molecular cytogenetic characterization of a 2 years and 4 months old female child with partial trisomy 7q22 → qter. This is the first such reported case resulting from a parental balanced translocation involving the long arms of chromosomes 7 and 14. The phenotype of the proband was compared with that of previously reported cases of trisomy 7q21 → qter or 7q22 → qter resulting from parental balanced translocations. CASE PRESENTATION: The proband was born pre-term to a 34-year-old mother with a history of two first trimester miscarriages and an early infant death. She was referred at the age of 8 months for genetic evaluation due to prenatal and postnatal growth retardation, developmental delay and multiple congenital anomalies. On clinical evaluation, she had craniofacial dysmorphic features such as scaphocephaly, large anterior fontanelle with open posterior fontanelle, prominent occiput, triangular face, high forehead, hypertelorism, down slanting eyes, flat nasal bridge, small nose, low set ears, micro-retrognathia, high arched palate and short neck. Cranial computerized tomography scan showed lateral ventriculomegaly with features of early cerebral atrophy. Conventional cytogenetic analysis showed the karyotype 46,XX,der(14)t(7;14)(q22;q32)mat in the proband due to an unbalanced segregation of a maternal balanced translocation t(7;14)(q22;q32). Fluorescence in-situ hybridization analysis confirmed the partial trisomy 7q22 → qter in the proband with a minimal loss of genetic material on chromosome 14. Single nucleotide polymorphism array further confirmed the duplication on chromosome 7q22.1 → qter and a small terminal deletion on chromosome 14q32.3 → qter. CONCLUSION: We report the longest-surviving child with trisomy 7q22 → qter due to a parental balanced translocation between chromosomes 7 and 14. Clinical features observed in the proband were consistent with the consensus phenotype of partial trisomy 7q22 → qter reported in the scientific literature. Early diagnosis of these patients using molecular cytogenetic techniques is important for establishing the precise diagnosis and for making decisions pertaining to the prognostication and management of affected individuals.

Partial trisomy 16q21➔qter due to an unbalanced segregation of a maternally inherited balanced translocation 46,XX,t(15;16)(p13;q21): a case report and review of literature.

BACKGROUND: Partial trisomy is often the result of an unbalanced segregation of a parental balanced translocation. Partial trisomy16q is characterized by a common, yet non-specific group of craniofacial dysmorphic features, and systemic malformations with limited post-natal survival. Most of the cases of partial trisomy 16q described in the scientific literature have reported only one, or less frequently two cardiac defects in the affected babies. Herein, we report a case of partial trisomy 16q21➔qter with multiple and complex cardiac defects that have not previously been reported in association with this condition. CASE PRESENTATION: We report the phenotypic and cytogenetic features of a Sri Lankan female infant with partial trisomy 16q21➔qter. The baby had a triangular face with downslanting eyes, low set ears and a cleft palate. Systemic abnormalities included multiple cardiac defects, namely double outlet right ventricle, ostium secundum atrial septal defect, mild pulmonary stenosis, small patent ductus arteriosus, and bilateral superior vena cavae. An anteriorly placed anus was also observed. The proband was trisomic for 16q21➔qter chromosomal region with a karyotype, 46,XX,der(15)t(15;16)(p13;q21)mat. The chromosomal anomaly was the result of an unbalanced segregation of a maternal balanced translocation; 46,XX,t(15;16)(p13;q21). Partial trisomy 16q was established by fluorescence in-situ hybridization analysis. CONCLUSIONS: The craniofacial dysmorphic features and the presence of cardiac and anorectal malformation in the proband are consistent with the phenotypic spectrum of partial trisomy 16q reported in the scientific literature. More proximal breakpoints in chromosome 16q are known to be associated with multiple cardiac abnormalities and poor long-term survival of affected cases. This report presents a unique case with multiple, complex cardiac defects that have not previously been described in association with a distal breakpoint in 16q. These findings have important diagnostic and prognostic implications.

Genetic determinants of inherited susceptibility to hypercholesterolemia - a comprehensive literature review.

Hypercholesterolemia is a strong determinant of mortality and morbidity associated with cardiovascular diseases and a major contributor to the global disease burden. Mutations in four genes (LDLR, APOB, PCSK9 and LDLRAP1) account for the majority of cases with familial hypercholesterolemia. However, a substantial proportion of adults with hypercholesterolemia do not have a mutation in any of these four genes. This indicates the probability of having other genes with a causative or contributory role in the pathogenesis of hypercholesterolemia and suggests a polygenic inheritance of this condition. Here in, we review the recent evidence of association of the genetic variants with hypercholesterolemia and the three lipid traits; total cholesterol (TC), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C), their biological pathways and the associated pathogenetic mechanisms. Nearly 80 genes involved in lipid metabolism (encoding structural components of lipoproteins, lipoprotein receptors and related proteins, enzymes, lipid transporters, lipid transfer proteins, and activators or inhibitors of protein function and gene transcription) with single nucleotide variants (SNVs) that are recognized to be associated with hypercholesterolemia and serum lipid traits in genome-wide association studies and candidate gene studies were identified. In addition, genome-wide association studies in different populations have identified SNVs associated with TC, HDL-C and LDL-C in nearly 120 genes within or in the vicinity of the genes that are not known to be involved in lipid metabolism. Over 90% of the SNVs in both these groups are located outside the coding regions of the genes. These findings indicates that there might be a considerable number of unrecognized processes and mechanisms of lipid homeostasis, which when disrupted, would lead to hypercholesterolemia. Knowledge of these molecular pathways will enable the discovery of novel treatment and preventive methods as well as identify the biochemical and molecular markers for the risk prediction and early detection of this common, yet potentially debilitating condition.

Ring Chromosome 4 in a Child with Multiple Congenital Abnormalities: A Case Report and Review of the Literature.

A female child born preterm with intrauterine growth retardation and presenting with facial dysmorphism with clefts, microcephaly, limb deformities, and congenital abnormalities involving cardiovascular and urinary systems is described. Chromosomal analysis showed a de novo 46,XX,r(4)(p15.3q35) karyotype. The clinical features of the patient were compared with the phenotypic characteristics of 17 previously reported cases with ring chromosome 4 and those with Wolf-Hirschhorn syndrome (4p-). Clinical features observed in this case are consistent with the consensus phenotype in ring chromosome 4. Patent ductus arteriosus and bilateral talipes equinovarus observed in this baby widen the phenotypic spectrum associated with ring chromosome 4.

HLA-B27 allele frequency in Sri Lankan patients with spondyloarthritides.

This preliminary study aims to describe the HLA-B27 allele frequency in Sri Lankan patients with spondyloarthritides (SA). An anonymised database of 373 Sri Lankan patients with SA referred for HLA-B27 testing was retrospectively analysed. Eighty five (22.8%) patients were positive for the HLA-B27 allele. A male preponderance was observed among the positives. The HLA-B27 allele frequency in this sample of patients with SA was relatively low compared to published studies in other populations. Further research is needed to identify the predominant subtypes of the allele to determine which subtypes are the most prevalent in a larger sample of Sri Lankan patients with SA, and to define their association with the specific types of SA.

Androgen insensitivity syndrome in a cohort of Sri Lankan children with 46, XY disorders of sex development (46, XY DSD).

INTRODUCTION: There are several conditions giving rise to 46, XY disorders of sex development (DSD) with different modes of inheritance. Therefore definitive diagnosis based on molecular genetic confirmation would be the ideal to counsel parents regarding the future implications of the condition affecting their baby. This is the first report from Sri Lanka documenting the presence of mutations in the androgen receptor (AR) gene in a cohort of children with 46, XY DSD. OBJECTIVES: To describe the socio-demographic and clinical features and document the presence of mutations in the androgen receptor (AR) gene in a cohort of children with 46, XY DSD. METHODS: 46, XY patients with ambiguous genitalia followed up in the University Unit at the Lady Ridgeway Hospital, Colombo, and clinically identified as having androgen insensitivity syndrome (AIS) or a testosterone biosynthetic defect were recruited for the study. Their socio-demographic details and clinical features were documented. Exons 1 to 8 of the AR gene were screened for mutations by DNA sequencing on a venous blood sample. SRY gene mutations were also assayed. RESULTS: Thirty-four patients were studied, 3 of whom were clinically diagnosed as having complete androgen insensitivity syndrome (CAIS). Sex of rearing was female and male in 4 and 30 respectively. AR gene mutations were detected in 6 patients (17.6%). None of the patients had SRY gene mutations. CONCLUSIONS: Majority (88%) of the patients were raised as males. Six patients (17.6%) including the 3 with CAIS, had genetically confirmed AIS with the detection of AR gene mutations.

CD4+ T-lymphocyte counts in patients with human immunodeficiency virus type 1 (HIV-1) and healthy population in Jos, Nigeria.

This study was undertaken to establish local CD4+LC standards, which could be used as indicators of immune deficiency or monitor progress of HIV therapy, instead of relying on Caucasian standards, which may not exactly reflect Nigerian CD4+LC sub-populations. CD4+LC from 1232 Nigerian adults were studied. They included 852 apparently healthy individuals, 172 HIV-positive persons with no major AIDS defining illnesses (AIDSDIL) and 208 HIV infected individuals with AIDSDIL. The mean CD4+LC of healthy Nigerians (821 +/- 12) was more than two times higher than the mean CD4+LC of HIV-positive individuals without AIDSDIL (369 +/- 14) and almost five times higher than the mean of HIV-positive individuals with AIDSDIL (163 +/- 13) (p < 0.05). In addition, a CD4+LC of < 200 cells/uL can be considered as an AIDS defining laboratory criterion in Nigerians as the 208 individuals with AIDSDIL had a mean CD4+LC of 163 cells/uL. This study therefore establishes a local standard range for CD4+LC in healthy and HIV infected Nigerians which can serve as reliable indices for HIV induced immune impairment and for monitoring effectiveness of HIV therapy.

Renal disease in the acquired immunodeficiency syndrome in north central Nigeria.

BACKGROUND: The brunt of the human immunodeficiency virus infection/the acquired immunodeficiency syndrome is largely borne by communities in sub-Saharan Africa. We describe renal disease in Nigerians with the acquired immunodeficiency syndrome. METHODS: Consecutive patients with the acquired immunodeficiency syndrome (AIDS) seen in the infections unit of the Jos University Teaching Hospital and a similar group of healthy controls were evaluated for renal disease. Subjects with past history of renal disease, hypovolemia, hypertension, diabetes mellitus and/or a documented fever were excluded from the study. RESULTS: Of the 79 patients with the acquired immunodeficiency syndrome and 57 controls studied, renal disease was present in 41 (51.8%) of the patients in the AIDS group and 7 (12.2%) of controls. While 15 (19%) of the AIDS group had azotemia alone and 20 (25.3%) had proteinuria alone, 6 (7.6%) had azotemia and proteinuria. The mean protein excretion/24 hours was significantly higher in the AIDS group compared to controls, (2.99 +/- 54 g and 0.56 +/- 0.12 g respectively, p = 0.001), while the GFR was significantly higher in controls compared to the study group (103.30 +/- 37.78 and 68.03 +/- 37.55 respectively, p = 0.004). Subjects in the AIDS group with renal disease had a significantly longer duration of illness compared to those without (12.33 +/- 8.67 months and 7.28 +/- 7.78 months respectively, p = 0.008). Age and serum CD4+ cell counts were similar in patients with and without renal disease in the AIDS group. CONCLUSION: Renal disease is a common complication of acquired immunodeficiency syndrome, the duration of illness being strongly associated with its presence.

Carriage rate of hepatitis-B surface antigen (HBsAg) in an urban community in Jos, Plateau State, Nigeria.

The carriage rate of Hepatitis-B surface antigen (HBsAg) in an urban community in Jos, the Plateau State capital, was studied to obtain the pattern of Hepatitis-beta virus (HBV) spread within the community. HBsAg screening was performed on a consecutive sample of 524 apparently healthy individuals (293 males and 231 females) aged 15-65 years who voluntarily turned up for the survey. Fifty-four (10.3%) were HBsAg positive by ELISA. The carriage rate in females 30/231 (13.0%) was significantly higher than in the males 24/293 (8.2%) (p<0.05). In relation to age, 14/144 (9.7%) were aged <20 years, 11/121 (9.1%) were 21-30 years, 7/115 (6.1%) were 31-40 years, 14/89 (15.7%) were 41-50 years, 2/27 (7.4%) were 51-60 years and 6/28 (21.4%) were >61 years. In relation to marital status, carriage rate was highest among the divorced/widowed group (12.5%) followed by the married group (10.6%). Carriage rates in relation to occupation showed that infection was highest among traders (13.7%) and students (13.2%). The survey therefore confirms the endemicity of HBV infection in Jos and describes the groups that are at risk. This calls for health education of the general population on preventive measures to check the spread of the virus in the community.