An audit of mammographic screen detected lesions of uncertain malignant potential (B3) diagnosed on initial image guided needle biopsy: how has our practice changed over 10 years?

AIM: To review all cases of B3 lesion diagnosed at initial image-guided needle biopsy over two 5-year cohorts to identify upgrade rates to malignancy and the effect of changing guidance on the management of such lesions. MATERIALS AND METHODS: Data was collected retrospectively. Mammographic features, biopsy type and management were recorded for each lesion. Upgrade rates for each B3 histological category were quantified. Statistical analysis was performed using SPSS. RESULTS: There were 224 cases in 2005-2010 and 240 cases in 2010-2015. Mammographically 211 lesions were microcalcifications, 182 masses, 65 distortions and six asymmetric densities with no difference in the mammographic features in the two cohorts. Two hundred and eight 14 G core biopsies and 256 initial vacuum-assisted biopsies were performed. There was a statistically significant reduction in benign surgical biopsies and an increase in second-line vacuum biopsy/excision in the latter cohort, with no significant change in the upgrade rate. There was an overall 6% upgrade to invasive malignancy and 13% upgrade to ductal carcinoma in situ (DCIS). The upgrade rates for the following histological categories were atypical intraductal epithelial proliferation (AIDEP) 33.2% (21/63); classical (not pleomorphic) in situ lobular neoplasia (ISLN) 18.2% (6/33); flat epithelial hyperplasia (FEA) 21.7% (20/92); papilloma with atypia 53.8% (7/13), without atypia 12.1% (8/66); and radial scar/complex sclerosing lesion with atypia 16.7% (2/12), and without atypia 7.9% (6/76). CONCLUSION: Upgrade rates remain high for some histological categories even with first-line use of vacuum biopsy. Management of borderline lesions should be considered carefully in a multidisciplinary meeting. In many cases, the need for diagnostic surgical excision has been replaced by image-guided vacuum sampling.

Can digital breast tomosynthesis accurately predict whether circumscribed masses are benign or malignant in a screening population?

AIM: To evaluate whether digital breast tomosynthesis (DBT) can predict if circumscribed masses are benign or malignant by assessing margin sharpness. MATERIALS AND METHODS: Circumscribed masses were evaluated on co-registered two-dimensional digital mammography (2DDM) and DBT. Lesions were categorised as follows: category 1=visible sharp border 0-25% of the total margin; category 2 = 26-50% category 3= 51-75%, and category 4=76-100%. Changes in category between 2DDM and DBT were analysed; if the category was lower on DBT the change was negative, if higher the change was positive. RESULTS: Of 759 lesions, 121 masses classified as circumscribed on DBT were included; 25 were malignant and 96 benign. Of the benign lesions, 8/96 were within category 3 or 4 on 2DDM compared with 48/96 benign lesions within category 3 or 4 on DBT (Fisher's exact test p<0.000527). Forty-eight of 51 (94.1%) lesions categorised as 3 or 4 on DBT were benign and 65/67 (97.01%) of the positive category change group were benign. Lesions in category 1 on DBT had 45.4% chance of being malignant (20/44) compared with 22.72% (20/88) on 2DDM (chi-squared test p<0.001). Sixty-five of 67 (97.01%) lesions in the positive category change group were benign and 23/54 (42.6%) lesions with either no or negative category change were malignant. CONCLUSION: The present study demonstrates 97% accuracy in predicting circumscribed lesions as benign when using positive category change and 94% accuracy when >50% of the margin is sharply defined on DBT.

Cryptogenic cirrhosis is the leading cause for listing for liver transplantation in Sri Lanka.

Hepatitis B and C are rare in Sri Lanka. Nonalcoholic fatty liver disease is increasing in the country. Eighty-one patients referred for liver transplantation (LT) over a period of 18 months were prospectively evaluated. Ninety-two percent (n = 74) were males. Cryptogenic cirrhosis was the leading indication for LT (58%, n = 47) followed by alcohol in 27% (n = 33). Hepatitis B and C were not seen in our cases. The liver biochemistry and clinical status of cirrhosis were similar in cryptogenic and alcoholic cirrhotics. Fourteen patients died while waiting for transplant, and nine transplants were performed. Cryptogenic cirrhosis is the leading cause for LT in Sri Lanka.

Proximal and distal rectal cancers differ in curative resectability and local recurrence.

AIM: To evaluate patients with proximal rectal cancer (PRC) (> 6 cm up to 12 cm) and distal rectal cancer (DRC) (0 to 6 cm from the anal verge). METHODS: Two hundred and eighteen patients (120 male, 98 female, median age 58 years, range 19-88 years) comprised 100 with PRC and 118 with DRC. The proportion of T1, T2 vs T3, T4 stage cancers was similar in both groups (PRC: T1+T2 = 29%; T3+T4 = 71% and DRC: T1+T2 = -31%; T3+T4 = 69%). All patients had cancer confined to the rectum - those with synchronous distant metastasis were excluded. Surgical resection was with curative intent with or without pre-operative chemoradiation (c-RT). Follow-up was for a median of 35 mo (range: 12 to 126 mo). End points were: 30 d mortality, complications of operation, microscopic tumour- free margins, resection with a tumour-free circumferential margin (CRM) of 1 to 2 mm and > 2 mm, local recurrence, survival and the permanent stoma rate. RESULTS: Overall 30-d mortality was 6% (12): PRC 7 % and DRC 4%. Postoperative complications occurred in 14% with PRC compared with 21.5% with DRC, urinary retention was the complication most frequently reported (PRC 2% vs DRC 9%, P = 0.04). Twelve percent with PRC compared with 37% with DRC were subjected to preoperative c-RT (P = 0.03). A tumour-free CRM of 1 to 2 mm and > 2 mm was reported in 93% and 82% with PRC and 88% and 75% with DRC respectively (PRC vs DRC, P > 0.05). However, local recurrence was 5% for PRC vs 11% for DRC (P < 0.001). Three and five years survival was 65.6% and 60.2% for PRC vs 67% and 64.3% for DRC respectively. No patient with PRC and 23 (20%) with DRC received an abdomino-perineal resection. CONCLUSION: PRC and DRC differ in the rate of abdomino-perineal resection, post-operative urinary retention and local recurrence. Survival in both groups was similar.

Uses of a familial adenomatous polyposis registry.

OBJECTIVES: To improve the prognosis of patients with familial adenomatous polyposis (FAP) by early diagnosis and prophylactic treatment through a coordinated FAP register. DESIGN: The establishment and descriptive analysis of the prospective database of the FAP registry. SETTING: University surgical unit, Colombo North Teaching Hospital Ragama, Sri Lanka. PATIENTS: Probands were identified by tracing all diagnosed FAP patients from 1996 to 2010 and their family members at risk. INTERVENTIONS: The establishment of a polyposis register included the following stages: ascertainment of probands (first contact symptomatic FAP patients), construction of pedigrees, counselling relatives and prophylactic screening of family members at risk, treatment and follow up. RESULTS: Twenty seven enrolled probands (12 male and 15 female, age 11-52 years, median age 34 years) were investigated. Pedigree analyses showed 206 relatives at risk. Twenty four family members at risk were screened of a total of 51 registered individuals. The rate of spontaneous mutations was 41%. Thirty five were diagnosed with FAP. Eight were screen detected (median age - 32 years) and 27 symptomatic (median age - 34 years). Concomitant colorectal cancer was detected in 17 (63%) symptomatic individuals and in 1 (13%) screen detected individual. Colectomy was performed in 27 (77%) patients while 8 (23%) are on chemoprophylaxis. Congenital hypertrophic retinal pigment epithelium was detected in 15. Desmoids tumours (6%) and other extraintestinal manifestations including osteomas, sebacious cysts and dental abnormalities (34%) were also detected. A thyroid gland malignancy was screen detected while retinoblastoma, hepatoblastoma and cerebral tumours were seen in pedigrees. CONCLUSIONS: A polyposis register may improve prognosis of FAP by early detection. It will help coordinate, optimise and streamline clinical management of patients with FAP and their relatives at risk.

Neutralizing human monoclonal antibodies binding multiple serotypes of botulinum neurotoxin.

Botulism, a disease of humans characterized by prolonged paralysis, is caused by botulinum neurotoxins (BoNTs), the most poisonous substances known. There are seven serotypes of BoNT (A-G) which differ from each other by 34-64% at the amino acid level. Each serotype is uniquely recognized by polyclonal antibodies, which originally were used to classify serotypes. To determine if there existed monoclonal antibodies (mAbs) capable of binding two or more serotypes, we evaluated the ability of 35 yeast-displayed single-chain variable fragment antibodies generated from vaccinated humans or mice for their ability to bind multiple BoNT serotypes. Two such clonally related human mAbs (1B18 and 4E17) were identified that bound BoNT serotype A (BoNT/A) and B or BoNT/A, B, E and F, respectively, with high affinity. Using molecular evolution techniques, it proved possible to both increase affinity and maintain cross-serotype reactivity for the 4E17 mAb. Both 1B18 and 4E17 bound to a relatively conserved epitope at the tip of the BoNT translocation domain. Immunoglobulin G constructed from affinity matured variants of 1B18 and 4E17 were evaluated for their ability to neutralize BoNT/B and E, respectively, in vivo. Both antibodies potently neutralized BoNT in vivo demonstrating that this epitope is functionally important in the intoxication pathway. Such cross-serotype binding and neutralizing mAbs should simplify the development of antibody-based BoNT diagnostics and therapeutics.

Detection of micrometastases in lymph nodes using reverse transcription polymerase chain reaction (RT-PCR) for cytokeratin 20 (CK-20)--a pilot study.

OBJECTIVES: The aim of the study was to detect micrometastases in lymph nodes in patients with rectal cancer following neoadjuvant therapy, staged node negative by routine histology. PATIENTS AND SETTING: Mesenteric lymph nodes from patients who have undergone neoadjuvant therapy for rectal cancer were harvested during surgery. Nodes were bisected and one half was sent for haematoxylin and eosin (H&E) staining and evaluated by a single pathologist. The other half was examined for CK20 by RT-PCR. The technique was validated by testing mesenteric lymph nodes with known metastases and nodes from patients without cancer. Twenty one lymph nodes from 6 patients (median age 46 years, range 25-55) which were negative for tumour deposits by H & E stain were assessed for micro-metastases. RESULTS: All 21 nodes which were histologically negative for metastases were positive for micrometastases. Two nodes with known metastases were positive for CK20 and 3 nodes from non cancer patients were negative for CK20. CONCLUSIONS: Detection of CK20 is accurate in identification of rectal cancer micro-metastasing to lymph nodes. Assessment of nodes by H & E histology risks under staging.

Synchronous liver metastasis in colorectal cancer in Sri Lanka.

OBJECTIVE: To assess the incidence of synchronous colorectal liver metastasis in patients referred to a tertiary referral center in Sri Lanka and to evaluate the differences in the clinicopathological features of patients with and without synchronous metastasis. METHODS: Records of 438 patients were retrospectively analyzed. Patients were classified into metastatic group (n = 34, 8%) and non metastastatic group (n = 404, 92%). In the two groups macroscopic features compared were: tumor size (2 cm, 2-5 cm, and >5 cm), site of primary tumor and side of liver involved. Carcinoembryonic antigen (CEA) levels were recorded. At microscopy, tumor differentiation, invasion and nodal status were evaluated. RESULTS: The rectum was the primary site of the tumor in a majority (60%) of patients. There was no difference in the distribution of the primary site and size of the tumor, pathological stage, lymphatic infiltration and the degree of tumor differentiation in two groups (p > 0.05). Patients with metastasis had higher levels of CEA, higher frequency of vascular infiltration and N3 nodes involved (p < 0.05). CONCLUSION: The incidence of synchronous colorectal liver metastasis seems to be lower in our patients. Association of higher CEA level, advanced nodal stage and presence of vascular invasion needs to be further assessed with risk of developing metachronous liver metastasis.

Patients with rectal cancer having neoadjuvant chemoradiation do not have increased complications of ileostomy closure.

OBJECTIVES: It is conceivable that reversal of an ileostomy after low anterior resection following neoadjuvant therapy (NAT) may involve anastomosis of small bowel exposed to irradiation. The aim was to evaluate peri-operative complications of ileostomy closure and to compare the histology of ileal mucosa in excised stomas in patients who received NAT with those without NAT. METHODS: Twenty patients who underwent rectal excision following NAT for cancer, were compared with 20 control patients who underwent rectal excision without NAT. All patients received a diverting loop ileostomy which was subsequently reversed with excision of the ileostomy. The clinical outcome and histopathological features after reversal were evaluated. RESULTS: There was no significant difference with regard to peri-operative complications such as post-operative deaths related to ileostomy closure, anastomotic leakage, retraction of stoma or small bowel fistulae. Resection margins revealed no significant difference in crypt distortion, depletion of mucin, acute inflammation, chronic inflammation and infiltration of eosinophils following NAT compared with controls. CONCLUSIONS: Neoadjuvant therapy for rectal cancer does not result in higher morbidity following closure of diverting loop ileostomy or result in significant inflammatory changes in the ileum. Therefore ileostomy closure is as safe in those with preoperative radiotherapy as in those without neoadjuvant therapy.

Sexual and urinary dysfunction following rectal dissection compared with segmental colectomy.

INTRODUCTION: The aim of this study was to assess the impact of nerve sparing surgery and major abdominal surgery on sexual and urinary function in men and women with colorectal cancer undergoing rectal dissection and segmental colectomy. METHOD: Forty-eight patients (group A: 22 males, 26 females; median age 55 years) undergoing rectal dissection were compared with 24 having segmental colectomy (group B: 12 male, 12 female; median age 55 years). Preoperative data were also compared with age- and gender-matched controls (group C). RESULTS: More patients after rectal dissection vs segmental colectomy had urinary tract infections [15 (31%) vs 3 (17.5%), P = 0.04]. At 37 months, urinary dysfunction after rectal excision was seen in 29 (60%; 20 men) vs nine (37.5%; eight men) after segmental colectomy. Postoperative urinary symptoms were significant in group A, but not in group B (pre: vs post; groups A and B: poor stream--13%vs 38%, P = 0.001 and 21%vs 21%, P = NS; incontinence--4.2%vs 17%, P = 0.008 and 8%vs 8%, P = NS; hesitancy--13%vs 35%, P = 0.034 and 17%vs 21%, P = NS). Sexual health was worse after rectal excision compared with segmental colectomy (men--62.5%, women--25%vs 44% of men) respectively. Erectile dysfunction was the chief cause (rectal excision--50%vs segmental colectomy - 33%). After rectal excision, 6% of women had dyspareunia and 19% reported reduced orgasm but none after segmental colectomy. Conclusion More men than women had urinary and sexual impairment after rectal excision than after segmental colectomy. Its aetiology is multifactorial.

Complications of loop ileostomy and ileostomy closure and their implications for extended enterostomal therapy: a prospective clinical study.

INTRODUCTION: Patients who have a temporary loop ileostomy have impaired quality of life. Complications associated with a loop ileostomy or ileostomy closure will impair patients' quality of life further and require extended enterostomal therapy. We performed a prospective audit of loop ileostomy to ascertain the nature of the workload that may be created with ileostomy-related complications. PATIENTS AND METHODS: One hundred and forty patients (67 males, 73 females, median age 50 years, range 5-90 years) who received a temporary loop ileostomy were analysed after completion of proformas on a prospective basis between 1999 and 2006. RESULTS: Operation was performed for rectal cancer 100 (71%), familial adenomatous polyposis 14 (10%), ulcerative colitis 21 (15%) and for trauma or Hirchsprung's disease 5 (3%). Complications of loop ileostomy were: retraction 1 (0.7%), ileostomy flux 11 (8%), stomal prolapse 1 (0.7%), parastomal hernia 1 (0.7%), paraileostomy abscess 4 (3%) and severe skin excoriation 9 (6%). The loop ileostomy was reversed in 117 (83%) at a median (range) of 13 weeks (1-60). Ileostomy closure-related complications were: small bowel fistula 1 (0.9%), small bowel obstruction 5 (4.3%) and a stitch sinus in 1 (0.9%). Five women developed recto-vaginal fistula (n=3; 2.6%), pouch-vaginal fistula (n=1; 0.9%) and pouch-anal fistula (n=1; 0.9%) that required extended enterostomal therapy, after loop ileostomy reversal. CONCLUSION: Nineteen percent of patients following creation of a loop ileostomy and 10.5% of patients after reversal of the ileostomy required extended enterostomal care by a specialized enterostomal therapist, which supported resumption of a normal life.

Glycosylation and the activation of proteinase-activated receptor 2 (PAR(2)) by human mast cell tryptase.

1. Human mast cell tryptase appears to display considerable variation in activating proteinase-activated receptor 2 (PAR(2)). We found tryptase to be an inefficient activator of wild-type rat-PAR(2) (wt-rPAR(2)) and therefore decided to explore the factors that may influence tryptase activation of PAR(2). 2. Using a 20 mer peptide (P20) corresponding to the cleavage/activation sequence of wt-rPAR(2), tryptase was as efficient as trypsin in releasing the receptor-activating sequence (SLIGRL.). However, in the presence of either human-PAR(2) or wt-r PAR(2) expressing cells, tryptase could only activate PAR(2) by releasing SLIGRL from the P20 peptide, suggesting that PAR(2) expressed on the cells was protected from tryptase activation. 3. Three approaches were employed to test the hypothesis that PAR(2) receptor glycosylation restricts tryptase activation. (a) pretreatment of wt-rPAR(2) expressing cells or human embryonic kidney cells (HEK293) with vibrio cholerae neuraminidase to remove oligosaccharide sialic acid, unmasked tryptase-mediated PAR(2) activation. (b) Inhibiting receptor glycosylation in HEK293 cells with tunicamycin enabled tryptase-mediated PAR(2) activation. (c) Wt-rPAR(2) devoid of the N-terminal glycosylation sequon (PAR(2)T25(-)), but not rPAR(2) devoid of the glycosylation sequon located on extracellular loop-2 (PAR(2)T224A), was selectively and substantially (>30 fold) more sensitive to tryptase compared with the wt-rPAR(2). 4. Immunocytochemistry using antisera that specifically recognized the N-terminal precleavage sequence of PAR(2) demonstrated that tryptase released the precleavage domain from PAR(2)T25(-) but not from wt-rPAR(2). 5. Heparin : tryptase molar ratios of greater than 2 : 1 abrogated tryptase activation of PAR(2)T25(-). 6. Our results indicate that glycosylation of PAR(2) and heparin-inhibition of PAR(2) activation by tryptase could provide novel mechanisms for regulating receptor activation by tryptase and possibly other proteases.

Contractile actions of proteinase-activated receptor-derived polypeptides in guinea-pig gastric and lung parenchymal strips: evidence for distinct receptor systems.

1. We have measured the contractile activities and relative potencies (EC(50)s) of six thrombin PAR(1) receptor-derived receptor-activating peptides (PAR-APs): AparafluroFRChaCit-y-NH(2) (Cit-NH(2)); SFLLRNP(P7); SFLLRNP-NH(2) (P7-NH(2)); SFLLR (P5); SFLLR-NH(2) (P5-NH(2)); TFLLR-NH(2) (TF-NH(2)) and a PAR(2) receptor activating peptide [SLIGRL-NH(2) (SL-NH(2))] (a) in a guinea-pig lung peripheral parenchymal strip preparation and (b) in a gastric longitudinal smooth muscle preparation. 2. The relative potencies of the PAR-APs in the lung preparation (Cit-NH(2) congruent with TF-NH(2) congruent with P5-NH(2) > P7 congruent with P5 congruent with P7-NH(2); SL-NH(2) not active) differed appreciably from their relative potencies in the gastric preparation: Cit-NH(2) congruent with TF-NH(2) congruent with P7-NH(2) congruent with P5-NH(2) > P7 congruent with SL-NH(2). 3. The contractile actions of the PAR(1)-selective peptide, TF-NH(2) in the gastric preparation were entirely dependent on extracellular calcium and were blocked by tyrosine kinase inhibitors (genistein, tyrphostin 47/AG213, PP1) and by the cyclooxygenase inhibitor, indomethacin, whereas in the lung preparation, the PAR(1)-mediated contractile response was only partially dependent on extracellular calcium and was refractory to the actions of either tyrosine kinase inhibitors or indomethacin. 4. Partial sequencing of the PAR cDNAs detected by RT - PCR both in whole lung and in the peripheral parenchymal strip bioassay tissue demonstrated the presence of both PAR(1) and PAR(2) mRNA; the expression of PAR(2) was detected by immunohistochemistry. 5. The data point to the presence of distinct receptor systems for the PAR(1)-APs in guinea-pig lung parenchymal and gastric smooth muscle and indicate that PAR(2) does not regulate contractile activity in peripheral parenchymal guinea-pig lung tissue

Transcriptional regulatory elements of the human gene for cytochrome P450c21 (steroid 21-hydroxylase) lie within intron 35 of the linked C4B gene.

The CYP21 gene, which encodes P450c21, the adrenal steroid 21-hydroxylase needed for glucocorticoid synthesis, lies in the major histocompatibility locus only 2.3 kilobase pairs (kb) downstream from the C4 gene. A 300-base pair (bp) proximal promoter and two upstream regions within C4 are needed for expression of mouse CYP21; the human gene also has a proximal promoter, but upstream elements have not been studied. To search for upstream regulatory elements in human CYP21B, we examined up to 9 kb of 5'-flanking DNA by transient transfection into human adrenal NCI-H295A cells. The 300-bp proximal promoter had substantial activity, but constructs retaining the DNA between -4.6 and -5.6 kb had increased activity, indicating the presence of distal elements. This region does not correspond to the mouse upstream regions, lying further upstream within intron 35 of C4B, which encompasses the previously described "Z promoter." DNase I footprinting located two elements, F1 and F2, lying -186 to -195 bp and -142 to -151 bp upstream from the Z cap site (-4862 to -4871 and -4818 to -4827 bp upstream of the CYP21B cap site). Each element formed a specific DNA-protein complex and conferred orientation-independent expression to a heterologous promoter. Mutations abolished formation of the DNA-protein complexes but only partially decreased expression. We identified a third site, F3, lying at -33 to -42 bp from Z. Competitive gel mobility supershift assays and co-transfection studies with SF-1 produced in vitro indicate F2 and F3 bind SF-1; BLAST searches and Southwestern blotting suggest that NF-W2 may bind F1. These results indicate that the Z promoter is a component of the CYP21 promoter needed to drive its adrenal-specific expression and that CYP21 transcription elements within C4 have kept these two genes linked during evolution.

Assessment of the phenotypic range seen in Doyne honeycomb retinal dystrophy.

OBJECTIVE: Using molecular genetics as the basis for diagnosis, to assess the phenotype in the family originally described as having dominantly inherited Doyne honeycomb retinal dystrophy (DHRD) linked to chromosome 2p16. DESIGN: Clinical examination including fluorescein angiography was undertaken in 107 family members. Nine affected patients underwent electroretinography, perimetry, dark adaptometry, color-contrast sensitivity measurement, and autofluorescent fundus imaging. PATIENTS: The disease-associated haplotype used to allocate disease status was based on our further refinement of the DHRD locus to between loci D2S2739 and D2S378. The study identified 50 affected patients. In addition, previously published information on a further 8 individuals was used. The study population represented 6 generations of a 9-generation pedigree. RESULTS: Three types of deposits were seen: large, soft drusen at the macula and abutting the optic nerve head; small, hard deposits that in some patients radiated from the macula; and autofluorescent deposits. Most younger affected individuals exhibited small hard drusen only at the macula and had normal visual function. Information on 2 patients suggested that DHRD can be a cause of childhood-onset blindness. Advanced disease was associated with severe visual loss and posterior pole atrophy without signs of drusen. Advanced age was not invariably associated with severe visual loss. CONCLUSIONS: Previously identified characteristics of DHRD were confirmed and new features identified. Contrary to previous reports, the constancy and severity of radial (basal laminar) drusen seen clinically are the only features that can be used to differentiate between DHRD and malattia leventinese. The highly variable phenotype suggests that the influence of the DHRD-mutant gene may be modulated by other genetic and/or environmental factors.

The gene responsible for autosomal dominant Doyne's honeycomb retinal dystrophy (DHRD) maps to chromosome 2p16.

Degeneration in the macula region of the retina is a feature of a heterogeneous group of inherited, progressive disorders, causing blinding visual impairment. Autosomal dominant Doyne's honeycomb retinal dystrophy (DHRD) is characterised by the presence of drusen deposits at the level of Bruch's membrane in the macula and around the edge of the optic nerve head. We have studied 63 members of a large, nine-generation British pedigree by linkage analysis. Two-point analysis showed significant linkage to nine markers on the short arm of chromosome 2, a region overlapping that recently reported to be linked to Malattia leventinese. A maximum lod score (Zmax) of 7.29 (theta = 0.0) was obtained at marker locus D2S2251. Haplotype analysis of recombination events localised the disease to a 5 cM region between marker loci D2S2316 and D2S378. Striking clinical similarities between DHRD and the more common condition age-related macular degeneration (ARMD) suggest that the disease gene at this locus could be considered as the most likely candidate in future studies on ARMD.