One gene, many phenotypes

"Phenotype" is the visible or quantifiable effect of the expression of a gene, whereas the specific genetic constitution responsible for a phenotype is called "genotype". It was hoped that phenotype could be accurately predicted if the genotype could be characterized. But, the relationship between the genotype and phenotype is not straightforward. Similar genetic lesions can have entirely different phenotypes. In recent years, there has been tremendous progress in the understanding of the genetic basis of diseases. The extent to which it will be possible to relate findings at the DNA level to the clinical phenotype is difficult to delineate on many occasions. The elucidation of mechanisms underlying genotype-phenotype discrepancies is important as it will influence the use of DNA-based tests in the diagnosis, therapy and counseling of individuals affected with genetic disorders. This issue is pertinent to almost every aspect of medical practice and research in this post-genome era. In this article, we have tried to summarize those factors which are responsible for varied manifestations of lesion(s) in a single gene.

Intracameral Avastin dramatically resolves iris neovascularization and reverses neovascular glaucoma

PURPOSE

To report the biologic effect of intracameral bevacizumab in patients with iris neovascularization secondary to proliferative retinal vasculopathies.

METHODS

Sixteen eyes of 15 patients with iris neovascularization associated with or without neovascular glaucoma secondary to proliferative retinal vasculopathies received intracameral bevacizumab (1.25 mg). Ophthalmic evaluations included Snellen visual acuity (VA), complete ophthalmic iris angiography, and slit lamp photography. Main outcome measure was change in degree of iris neovascularization. Secondary outcomes included fluorescein iris angiographic leakage, control of intraocular pressure, and changes in VA.

RESULTS

All patients with neovascularization demonstrated by slit lamp photography and fluorescein angiography (16/16 eyes) had complete (or at least partial) reduction in leakage of the neovascularization within 3 weeks after the injection. Leakage from iris neovascularization resolved in 12 of 16 (75%) eyes. In two cases recurrent leakage was seen as early as 4 weeks necessitating repeat injection. Intraocular pressure was controlled with maximum medical therapy in eight of nine eyes reducing the need for glaucoma surgery. Visual acuity improved from a median of hand motions to 20/200.

CONCLUSIONS

In summary, intracameral bevacizumab was effective in reversing iris neovascularization in the majority of patients. It also facilitated intraocular pressure control in patients with associated glaucoma.

Uro-genital bleeding in pre-menarcheal girls: dilemmas of child abuse

Uro-genital bleeding in pre-menarcheal girls always raises concerns regarding child abuse. There are serious social issues involved; however, before labeling it as sexual abuse, all efforts must be made to rule out an organic pathology. We recently encountered two young girls of Afro-Caribbean origin who presented with vaginal bleeding with concerns from referring physicians about child/sexual abuse. On examination both had a rare condition of urethral prolapse. One of them underwent four-quadrant excision and the other was treated conservatively with urethral catherization.

Longitudinal brain MRI study in a mouse model of Rett Syndrome and the effects of choline

Rett Syndrome (RTT), the second most common cause of mental retardation in girls, is associated with mutations of an X-linked gene encoding the transcriptional repressor protein MeCP2. Mecp2(1lox) mutant mice express no functional MeCP2 protein and exhibit behavioral abnormalities similar to those seen in RTT patients. Here we monitor the development of both whole brain and regional volumes between 21 and 42 days of age in this model of RTT using MRI. We see decreases in whole brain volumes in both male and female mutant mice. Cerebellar and ventricular volumes are also decreased in RTT males. Previous work has suggested that perinatal choline supplementation alleviates some of the behavioral deficits in both male and female Mecp2(1lox) mutant mice. Here we show that perinatal choline supplementation also positively affects whole brain volume in heterozygous females, and cerebellar volume in male RTT mice.

Transaxillary endoscopic excision of benign breast lumps: a new technique

BACKGROUND

Benign breast lumps affect 10% of women in their lifetimes. Despite a favorable natural history enabling surveillance as an option, surgical excision continues to be popular. Avoiding a scar on the breast is an inherent feminine desire. Because the breast is a part with a high charge in the culture, women seek to keep it away from the surgical knife. Numerous minimally invasive approaches have evolved as a result of this psychology. These leave much to be desired. Circumareolar incision at best camouflages the scar, which still is sited on the breast. This scar is subject to the same sequelae as any other breast scar. The axilla, an anatomically contiguous space, provides easy access for endoscopic breast surgery. The authors used this access to excise benign breast lumps endoscopically. This spared the breast from a scar.

METHODS

Between January 2002 and March 2005, 14 women with benign breast lumps underwent surgery. Transaxillary endoscopic excision of 18 such lumps was performed.

RESULTS

A total of 14 women with 18 benign breast lumps underwent surgery. The mean operative time per patient was 66.78 min (range, 40-110 min). No axillary injury, bleeding, technical difficulty, surgical emphysema, conversion, hematoma, or rehospitalization occurred. All the women expressed their satisfaction and happiness with the operation.

CONCLUSION

Endoscopic excision of benign breast lumps is a safe and patient-friendly procedure.

Anti-androgens increase N-terminal pro-BNP levels in men with prostate cancer

OBJECTIVE

The aim of this study was to determine the effects of anti-androgens on left ventricular (LV) function and levels of N-terminal proB-type natriuretic peptide (NT-proBNP), a sensitive cardiac risk marker, in men with prostate cancer as these are widely used drugs in this condition, and evidence suggests that endogenous androgens are cardioprotective in men.

DESIGN AND PATIENTS

Forty-three men (mean age 70.7 +/- 6.2 years) with prostate cancer were randomized to goserelin (an LH-releasing hormone analogue) or bicalutamide (an androgen-receptor blocker) for 6 months; 20 men with a history of prostate cancer on no treatment were studied in parallel.

RESULTS

Mean changes in testosterone and oestradiol, respectively, from baseline to 6 months were -88% and -46% with goserelin, +50% and +44% with bicalutamide, and -1% and -9% for the 'no-treatment' group. Bicalutamide significantly increased NT-proBNP from baseline to 3 and 6 months (median value at baseline, 3 and 6 months: 55, 101 and 118 ng/l, respectively). Goserelin caused a significant increase from baseline to 3 months but not to 6 months (median value at baseline, 3 and 6 months: 66, 87 and 72 ng/l, respectively). No significant changes occurred in the 'no-treatment' cohort (median value at baseline 3 and 6 months: 60, 53 and 60 ng/l, respectively). No significant changes in LV function, blood pressure (BP), body mass index or waist-hip ratio occurred to account for the changes in NT-proBNP.

CONCLUSION

Androgen receptor blockade and, to a lesser extent, androgen suppression cause an increase in NT-pro-BNP in men with prostate cancer. The significance is not clear but could imply an adverse effect on cardiovascular risk following hormonal manipulation.

Rituximab effectively reverses papilledema associated with cerebral venous sinus thrombosis in antiphospholipid antibody syndrome

PURPOSE

A case of bilateral papilledema secondary to cerebral venous sinus thrombosis treated with Rituximab, an anti-CD20 monoclonal antibody.

METHODS

A 23 year old obese female with a one week history of blurred vision, headaches and vomiting presented with bilateral papilledema. Her BCVA was 20/50 in right eye and 20/200 in the left eye with severe reduction of visual fields. Laboratory investigations revealed thrombocytopenia, prolonged prothrombin time (not reversed when mixed with normal plasma) and anticardiolipin antibodies. Besides, cerebral angiogram showed presence of cerebral venous thrombosis. The patient to have anti phospholipid antibody syndrome and treated with rituximab I.V. 375 mg/m 2 weekly x 4 doses, acetazolamide 500 mg BID, methyl prednisolone I. V. QID x 4.

RESULTS

At 1-month, her headaches and vision improved to 20/30 in both eyes with partial resolution of papilledema and complete restoration of visual fields. Nine months later, patient had 20/25 vision in right eye and 20/30 in left eye with complete resolution of papilledema and cerebral sinus thrombosis.

CONCLUSIONS

Rituximab was effective in reversing papilledema and cerebral sinus thrombosis, while preserving the vision in patient with antiphospholipid antibody syndrome. It is efficacious in treating papilledema in patients refractory to treatment with systemic steroids and immunoglobulin, with better clinical compliance and no side effects.

Effect of gamma irradiation on blood from glucose 6 phosphate dehydrogenase deficient blood donors

Recently, the irradiation of cellular blood components has received increased attention. Normal red blood cells (RBC) when subjected to gamma irradiation show increase in haemolysis and increased storage lesions. Glucose 6 phosphate dehydrogenase (G6PD) deficient blood is lacking in anti-oxidant properties which protect the RBC membrane and therefore when subjected to gamma irradiation, it may lead to increased haemolysis. In this study, 500 healthy non-remunerated blood donors were screened for G6PD deficiency. About 350 ml of whole blood was collected from 10 G6PD deficient donors (cases) and 10 units were collected from donors who were not deficient for G6PD (controls). All units were subjected to gamma irradiation of 25 Gy by a self contained gamma cell irradiator (Nordion Canada) on day 0 and then stored at 4 degrees C. Sampling was done from these cases and controls on day 0, 7, 14 and 21. Estimation of free plasma hemoglobin (Hb), free plasma potassium (K) and lactate dehydrogenase (LDH) was performed. It was found that there were no significant changes between the cases and controls in any of the parameters assessed, although the values for all the parameters were higher in case group at the end of storage period, these differences were not statistically significant.

Metabolism of arachidonic acid in sheep uterus: in vitro studies

Arachidonic acid (AA) metabolism in the non-pregnant sheep uterus was studied in vitro using conventional chromatographic and HPLC techniques. High expression of both lipoxygenase (LOX) as well as cyclooxygenase (COX) enzymes and their activities was found in the uterine tissues. On incubation of uterine enymes with AA, the LOX products formed were identified as 5-hydroperoxyeicosatetraenoic acid (5-HPETE), 12- and 15-hydroxyeicosatetraenoic acids (12- and 15-HETEs), based on their separation on TLC and HPLC. By employing differential salt precipitation techniques, the LOXs generating products 5-HPETE (5-LOX), 12-HETE and 15-HETE (12- and 15-dual LOX) were isolated. Based on their analysis on TLC, the COX products formed were identified as prostaglandins - PGF2alpha and prostacyclin derivative 6-keto PGF1alpha. The study forms the first report on the comprehensive analysis on the metabolism of AA in sheep uterus in vitro via the LOX and COX pathways.

Sexing of human hip bones of Indian origin by discriminant function analysis

The present study was carried out in terms of discriminant analysis and was conducted on 100 human hip bones (of unknown sex) of Indian origin. Based on morphological features, each of the hip bone was rated on a scale of 1-3 for sexing. Twelve measurements and five indices were recorded. The results of discriminant function analysis showed that the acetabular height (vertical diameter) and indices 1 (total pelvic height/acetabular height), 2 (midpubic width/acetabular height) and 3 (pubic length/acetabular height) were very good measures for discriminating sexes. Pelvic brim depth, minimum width of ischiopubic ramus and indices 4 (pelvic brim chord x pelvic brim depth) and 5 (pubic length x 100/ischial length) were also good discriminators of sex. The remaining parameters were not significant as they showed a lot of overlap between male and female categories. The results indicated that one exclusive criterion for sexing was index 3 (pubic length/acetabular height). In comparison with the morphological criteria, the abovementioned index caused 25% and 10.25% increase in the hip bones of female and male category, respectively.

Association and interaction of the TNF-alpha gene with other pro- and anti-inflammatory cytokine genes and HLA genes in patients with type 1 diabetes from North India

Type 1 diabetes (T1D) is a multifactorial autoimmune disorder where major histocompatibility complex (MHC) genes and the insulin-linked polymorphic region have been shown to play major roles. We report here an integrated effect of tumor necrosis factor (TNF) alpha with other cytokine genes. The TNF-alpha-308 GA and AA (high secretor) polymorphisms were significantly increased in the patients with T1D (n = 235) [P < 7 x 10(-6), odds ratio (OR) = 3.04, 95% confidence interval (CI) = 1.8-5.3] compared with the controls (n= 128). The variants of interferon-gamma (IFN-gamma) (A(+874)T), interleukin (IL)-6 (G(-174)C), IL-10 (A(-1082)G, T(-819)C, C(-592)A) and transforming growth factor (TGF) beta1 (T(cdn10)C, G(cdn25)C) did not show a significant difference between patients and controls. However, simultaneous presence of TNF-alpha-308 GA+AA along with both high and low secretor genotypes of IFN-gamma (P < 0.003) was significantly increased in patients. Simultaneous presence of TNF-alpha-308 GA + AA along with high secretor genotypes of IL-6 (P < 0.0001, OR = 2.61, 95% CI = 1.5-4.56), IL-10 (P < 0.0001, OR = 4.26, 95% CI = 1.9-10.1) and TGF-beta1 (P < 0.00004, OR = 2.8, 95% CI = 1.6-4.86) was also significantly increased in patients with T1D. Low secretor genotype of TNF-alpha-308 GG along with low secretor genotypes of IFN-gamma (P < 0.001, OR = 0.465, 95% CI = 0.28-0.77), high secretor genotypes of IL-6 (P < 0.000004, OR = 0.76, 95% CI = 0.227-0.621) and TGF-beta1 (P < 0.000006, OR = 0.336, 95% CI = 0.198-0.568) was protective. The TNF-alpha-308 G allele was in linkage disequilibrium (LD) with the human leukocyte antigen (HLA)-B*0801-DRB1*0301 haplotype, while TNF-alpha-308 A allele was in LD with the HLA-B*5001-DRB1*0301 and B*5801-DRB1*0301 haplotypes, suggesting that the effect of TNF-alpha -308 A allele is not because of its being in LD with any HLA alleles, but because of its functional role and its integrated effect with other cytokines.

Spectrum of cytomorphology of tuberculous lymphadenitis and changes during anti-tubercular treatment

OBJECTIVE

To analyse the morphological changes in tuberculous lymph nodes and the clinical response during short course anti tubercular chemotherapy.

METHODS

Thirty-six patients with tuberculous lymphadenitis under treatment were followed up clinically and cytologically at 0, 2, 4 and 6 months.

RESULTS

Twenty-six (72.2%) patients had palpable lymph nodes at the end of chemotherapy. Of the 14 patients with residual lymph nodes exceeding 1 cm in size, 92.8% (13) still had evidence of continuation of the disease. Acid-fast bacilli could be found in 38.8% patients at the end of 6 months. Intense lymphocytic infiltration of granulomata in the early phase of chemotherapy predicted a favourable outcome.

CONCLUSIONS

Following completion of anti-tubercular treatment a significant percentage of patients have persistent lymphadenopathy and harbour the disease. Morphological follow up of these patients is essential as they may be at increased risk of relapse.

Chemokine and chemokine receptor analysis reveals elevated interferon-inducible protein-10 (IP)-10/CXCL10 levels and increased number of CCR5+ and CXCR3+ CD4 T cells in synovial fluid of patients with enthesitis-related arthritis (ERA)

Chemokines and chemokine receptors play a major role in homing of cells to the site of inflammation. Enthesitis-related arthritis (ERA) is a chronic inflammatory arthritis and no data are available on chemokines and their receptors in ERA. Blood (20) and synovial fluid (SF) (11) was collected from patients with ERA, and peripheral blood (PB) was collected from 12 patients with polyarticular juvenile idiopathic arthritis (JIA), nine patients with systemic onset and 18 healthy controls. Chemokines [interleukin (IL)-10/CXCL10, thymus and activation-regulated chemokine (TARC)/CCL17 and regulated upon activation normal T cell expressed and secreted (RANTES)/CCL5] were measured in serum and SF. Chemokine receptor expression was measured by flow cytometry. There was no difference in blood CD4(+) T cells bearing CCR5, CCR4 and CXCR3 in ERA and healthy controls. In paired samples the median frequency of CCR5(+) CD4(+) T cells was higher in SF compared to PB (15.8 versus 3.9%, P < 0.005), as was the frequency of CXCR3(+) T cells (21.61% versus 12.46%, P < 0.05). Median serum interferon-inducible protein-10 (IP-10)/CXCL10 levels were higher in patients with ERA compared to controls (139 versus 93 pg/ml; P < 0.05). Further median SF IP-10/CXCL10 levels were higher than the serum levels (2300 pg/ml versus 139 pg/ml; P < 0.01). Serum levels of RANTES/CCL5 were higher in patients (150 ng/ml) compared to control (99 ng/ml; P < 0.01). The SF levels were significantly lower compared to serum (P < 0.05). TARC/CCL17 levels in SF were lower than serum. There is increased homing of CCR5 and CXCR3(+) CD4 cells to the SF. Increased SF levels of IP-10/CXCL10 may be responsible for this migration in patients with ERA.