Cervicofacial Rhabdomyosarcoma - Success of a Free Fibular Graft.

Cervicofacial rhabdomyosarcoma (RMS) presents surgical complexities in children due to its aggressive nature. This study presents a successful case of oral RMS treatment with a free fibular graft in a 7-year-old patient. Despite follow-up challenges, the efficacy of the approach is evident.

A case of intradural lumbar disc herniation.

Key Clinical Message: MRI remains the best tool in the diagnosis of this disease entity however preoperative diagnosis remains a difficult task. A high degree of suspicion is raised when intraoperative findings and preoperative image description become incompatible. Abstract: Lumbar disc herniation into the dural space is a rare phenomenon of lumbar disc degeneration with an unclear remaining pathogenesis. Intraoperative ultrasonography and histopathological examination of resected specimen help in the diagnosis of intradural disc herniation. Prompt surgery is recommended due to the high incidence of cauda equina syndrome.

Orbital Apex Syndrome caused by invasive aspergillosis in patient with post-Covid-19 infection - A case report.

INTRODUCTION AND IMPORTANCE: Orbital Apex Syndrome (OAS) are characterized by multiple symptoms, such as impaired eye movement, periorbital pain, and visual disturbance. AS symptoms may be caused by inflammation, infection, neoplasm, or a vascular lesion, potentially involving a variety of nerves, such as the optic, oculomotor, trochlear or abducens, or the ophthalmic branch of the trigeminal nerve. However, OAS caused by invasive aspergillosis in post-COVID patient is a very rare phenomenon. CASE PRESENTATION: A 43-year-old male with a history of diabetes mellitus and hypertension who had recently recovered from a COVID-19 infection developed blurred vision on the left eye field, followed by impaired vision on left eye field for 2 months then retro-orbital pain for a further 3 months. The blurring of vision and headache developed soon after recovering from COVID-19 and was progressive in left eye field. He denied any symptoms of diplopia, scalp tenderness, weight loss, or jaw claudication. The patient was treated with IV methylprednisolone for 3 days with as diagnosis of optic neuritis, followed by a course of oral corticosteroid therapy (prednisolone, starting at 60 mg for 2 days and then tapered for 1 month), which produced transient relief of symptoms that recurred when prednisone was discontinued. Then repeat MRI was perform with no evidence of lesion; treated again in a line of optic neuritis and symptoms relief transiently. After reoccurrence of symptoms repeat MRI was perform which showed a heterogeneously enhancing intermediate signal intensity lesion in the left orbital apex. The lesion was encasing and compressing the left optic nerve, without abnormal signal intensity or contrast enhancement within the left optic nerve either proximal or distal to the lesion. The lesion was contiguous with focal asymmetric enhancement in the left cavernous sinus. No inflammatory changes were seen in the orbital fat. CLINICAL DISCUSSION: OAS due to invasive fungal infection is uncommon and most often caused by Mucorales spp., or Aspergillus, particularly in those with immunocompromising conditions or uncontrolled diabetes mellitus. In OAS due to Aspergillosis urgent treatment is necessary to avoid complications such as complete vision loss and cavernous sinus thrombosis. CONCLUSION: OASs, represent a heterogenous group of disorders that results from a number of etiologies. OAS in a background of COVID-19 pandemic can be due to invasive Aspergillus infection as in our patient without any systemic illness and lead to miss diagnosis and delay in proper treatment.

Spectrum of congenital lung and foregut malformations: scope for awareness and prompt management-a case series.

Congenital lung and foregut malformations have been described in literature, but most articles are from the Western world. There are a separate set of problems which are faced in our country especially with the misdiagnosis of these problems which has not so much been addressed in writing. We retrospectively reviewed records of all patients with above thoracic lesions treated at a tertiary care hospital in Delhi from March 2017 to December 2019. Twenty patients were found. Eight of 20 patients were detected antenatally but none monitored serially. Age at presentation ranged from 5 days to 18 months. Eight patients presented with respiratory distress at birth. Three of these were congenital lobar emphysema wrongly diagnosed as pneumothorax and brought with intercostal drainage tube inserted. Eight suffered from pneumonia, 4 of which had history of previous hospital admission but undetected congenital pathology. All underwent surgery and had good outcome. There was radiological evidence of compensatory lung growth in all patients at 6 months follow-up. Thus, we conclude that the antenatal detection of congenital lung and foregut malformations may have increased but proper serial monitoring is still missing. There is scope of increasing index of suspicion for these lesions among pediatricians and surgeons. With modern-day safe anesthesia, proactive resection of congenital lung and foregut malformations is associated with good outcome. Delaying treatment predisposes the child to infective complications and makes surgery difficult.

A case report of multiple isolated intradural neurocysticercosis of the lumbo-sacral spine.

INTRODUCTION AND IMPORTANCE: Neurocysticercosis is the most common parasitic infection of the nervous system and it is mostly intracranial. Intradural intramedullary or extramedullary is the rarest involvement of intraspinal cysticercosis. Its isolated involvement is even rare, as it usually has intracranial association. We aim to report a rare case of isolated intraspinal neurocysticercosis and discuss the measures we can take for early management. Despite being an eradicable disease of public health importance, its prevalence is increasing widely in developed countries too. Therefore, we aim to discuss its pathogenesis, mode of spread, and preventive aspects as well. PRESENTATION OF CASE: A 40-year-old woman presented to our hospital with pain over the lower back region radiating to the right thigh. Magnetic Resonance Imaging (MRI) of her lumbosacral spine revealed a cystic lesion at the spinal level L5-S1. We confirmed the diagnosis via Histopathological examination (HPE) following surgery. DISCUSSION: Isolated intradural neurocysticercosis of the spine is extraordinarily rare involvement. It is caused by the larval stage of taenia solium. An MRI is the preferred imaging modality. Due to rarity and nonspecific clinic-radiological findings, diagnosis may often be missed. In our case, MRI revealed a cystic lesion at the L5-S1 level of the spine and multiple cystic lesions at the level were found intra-operatively. Its diagnosis is confirmed by HPE. Treatment can be medical or surgical according to the severity of the disease. CONCLUSION: Although rare, neurocysticercosis can cause irreversible neurological damage. Therefore, surgeons should consider it in the differential diagnosis of intraspinal lesions.

Gastric pull-up by the retrosternal route for esophageal replacement: Feasibility in a limited-resource scenario.

OBJECTIVES: The authors herein report the results of esophageal replacement by gastric pull-up technique through the retrosternal route as an option for esophageal replacement in a resource-constrained setup. METHOD: Prospectively collected data upon twenty-two consecutive patients (male:female = 17:5) with mean age 24.9 months (7 months-12 years) and mean weight 7.9 kg (4.2-32 kg) who underwent retrosternal gastric pull-up for esophageal atresia (n = 18; 16 atresia with distal fistula & 2 pure atresia) and corrosive injuries to the esophagus (n = 4) over the past 8 years are presented. The management protocol and surgical technique have been described. Observations parameters included indication for esophageal replacement, age at surgery, sex of the child and other demographic details, clinical and operative findings, post-operative outcomes and follow-up details. RESULTS: Retrosternal gastric pull-up could be performed in all cases with no mortality or graft loss. Of 22, 20 cases were extubated on-table and 2 cases were extubated within 48 hours of surgery. Mean operative duration was 265 min (range: 175 min to 310 min) and blood loss was 115.3 ml (range: 80-400 ml). Dense vascular adhesions in the region of the esophageal hiatus were encountered in patients with abdominal esophagostomy (n = 4) which were probably related to the local dissection at the time of previous surgery. Minor anastomotic leak was observed in 8 of 22 patients which settled spontaneously over 21 days mean period (range: 18 to 31 days). Antegrade dilatation was required in 3 of 8 cases with minor leak. None of them required revision of anastomosis. Mean follow-up duration is 63 months (range: 11 months - 94 months). Weight gain after surgery was close to or beyond the 25th centile. Symptoms of dumping syndrome or GER were not observed in our cohort. CONCLUSION: Our data have demonstrated the safety and feasibility of esophageal replacement by gastric transposition through the retrosternal route in a resource-limited setup. No significant difference has been observed from the results and complications reported in literature for the same procedure. TYPE OF STUDY: Prospective observational study / treatment study. LEVEL OF EVIDENCE: Level III.

Primary anastomosis in difficult cases of type "C" esophageal atresia: The atraumatic microvascular clamp technique of minimal tension with good outcome.

BACKGROUND: Surgical maneuvers for esophageal anastomosis in difficult cases of Gross type "C" esophageal atresia (EA) are challenging. The methods of early primary anastomosis are technically difficult and staged surgeries expose the child to repeated general anesthesia with problems of nursing care. We describe a simple method of partial disconnection of the lower esophagus from the fistula followed by approximation by an atraumatic microvascular clamp. The suitability of this method and its outcomes are discussed. METHODS: It was a prospective observational study that included 32 patients of type "C" EA between January 2014 and December 2016. Babies with birth weight more than 2 kg without cyanotic heart defects and requirement of intensive care were included. An early primary anastomosis using this technique was tried in all. A cervical esophagostomy with feeding gastrostomy was done where it was not possible. Analysis of the gap and post operative outcomes i.e. gastroesophageal reflux (GER), stricture, tracheomalacia, dysmotility, recurrence and survival were analyzed. RESULTS: The mean gap between esophageal ends was 4.3 cm. Primary anastomosis was possible in 26 (81.25%). Minor and major leak occurred in 3 (11.54%) and 1 (3.85%) patients respectively. Survival was 84.62% (22/26). All mortalities were early post operative. During mean follow up of 23.73 months (till December 2019), GER decreased from 63.64% (14/22) to 13.64% (3/22), partial stricture was seen in 18.18% (4/22), tracheomalacia in 36.36% (8/22) and dysmotility in 77.27% (17/22). There was no recurrence of fistula. Complications with this method did not show any significant difference as mentioned with other methods. CONCLUSION: This technique seems to be physiologically suitable as it enables anastomosis with minimal trauma to the esophageal ends. It is easy, reproducible and produces favorable outcomes comparable with other methods for difficult cases of type "C" esophageal atresia (EA).

Outcomes of preputioplasty in patients undergoing TIP urethroplasty (tubularization of incised urethral plate) for distal and mid penile hypospadias.

BACKGROUND: Preputioplasty as a part of hypospadias repair restores the normal appearance of phallus, which is especially important in distal and mid penile hypospadias. However possibility of its inherent complications such as iatrogenic phimosis or preputial breakdown are the cause of controversy and reluctance regarding this procedure.This study evaluates the results of preputial reconstruction with TIP urethroplasty in distal and mid penile hypospadias repair and analyses if preputioplasty may be offered to these patients. MATERIALS & METHODS: In this prospective observational study, 48 cases of distal and mid penile hypospadias underwent TIP urethroplasty and preputioplasty and results were assessed at 2 weeks, 3 months and 6 months. Major complications included preputial dehiscence, tight prepuce (iatrogenic phimosis) and minor complications included ventral tethering, persistent dorsal whorls and redundant prepuce. Data was analysed with Microsoft Excel spreadsheet where descriptive statistics were obtained. RESULTS: Preputioplasty was performed in 48 children with a mean age of 5.1 years. Preputioplasty dehiscence was seen in three (6%) patients, which gave an appearance of irregular prepuce on 6 m follow up. Two patients (4%) were confirmed to have preputial tightness at 3 months but this resolved conservatively in one patient and only one patient (2%) required circumcision for a tight prepuce. Minor complications included ventral tethering, persistence of dorsal whorls and redundant prepuce. Ventral tethering was present in 3 patients (6.25%). Redundant prepuce was observed in 2 patients (4.16%). Additionally, unsightly dorsal whorls were found to be persistent in 2 children (4.16%). None of these patients opted for circumcision. The rest of the children had a cosmetically and functionally normal prepuce. Two patients (4%) developed urethrocutaneous fistula at 3 months' follow-up. CONCLUSION: Preputial reconstruction is feasible with a good cosmetic outcome and minimal complications in patients of distal and mid penile hypospadias undergoing TIP urethroplasty. Mild preputial tightness evolves over time and resolves with conservative measures. In patients with very prominent dorsal whorls and underlying bulky tissues the preputioplasty does not appear to be of satisfactory cosmesis. To help the patient and parents take a well informed decision, it would be useful to explain all possible major and minor foreskin complications, and their rectification.

Sacrococcygeal Teratoma: Clinical Characteristics, Management, and Long-term Outcomes in a Prospective Study from a Tertiary Care Center.

INTRODUCTION: The study focuses on the clinical presentation, management, and outcomes (both short term and long term) in patients with sacrococcygeal teratoma managed over a decade in a tertiary care center. MATERIALS AND METHODS: This is a prospective study on children with sacrococcygeal teratoma over 12 years data collected included antenatal diagnosis, mode of delivery, age at diagnosis, clinical presentation, physical extent of mass (including Altman classification), levels of alpha-fetoprotein, surgical approach, histopathology, clinical outcome, recurrence and long-term results including bladder-bowel dysfunction and neurological impairment. Functional results were evaluated clinically and radiologically. RESULTS: During the study, 41 patients (male to female ratio of 1:3.1) with a median age of 36 days (1 day-11.6 years) with sacrococcygeal teratoma were managed at our center. The mean follow-up duration was 54 months (range 19-110 months). Nearly, two-thirds of the tumors were either Altman Type 1 or 2. Yolk sac tumor was present in 8 (19.5%) patients, while the rest has either mature or immature teratoma. Tumors were removed through a posterior sagittal or a chevron incision. In seven patients, abdominosacral approach was necessary. Eight patients with malignant disease received chemotherapy (neoadjuvant in 5). Overall survival was 95% at a mean follow-up of 54 months. Among the late complications, three patients had a local recurrence of tumor, and urinary dribbling was present in three patients. CONCLUSIONS: Teratomas are the most common germ cell tumors of the sacrococcygeal region. Most of the tumors are benign, and the incidence of malignancy increases with age. The evaluation of malignancy is, therefore, necessary in these children. Excellent survival of 95% was achieved in this series. Morbidity due to associated malformation, disease recurrence, and treatment may persist in these patients; hence, proper follow-up is needed.

Surgical Surprise during Posterior Sagittal Anorectoplasy: A Rectal Duplication.

An 8-month-old boy with anorectal malformation (ARM) was incidentally found to have double rectal pouches during posterior sagittal anorectoplasty. The distal blind-ending pouch was excised, and the larger proximal pouch was tapered and anorectoplasty performed. The excised pouch was confirmed as rectal duplication cyst. One must be aware of such uncommon associations with ARM.

Evaluation of two-staged Fowler-Stephens laparoscopic orchidopexy (FSLO) for intra-abdominal testes (IAT).

INTRODUCTION: The best operative intervention for intrabdominal testis (IAT) has not been standardized as yet. The question of whether to bring down an IAT with a single-staged vessel-intact laparoscopic orchidopexy (VILO) or a two-staged laparoscopic Fowler-Stephens orchidopexy (FSLO) is still undergoing debate, with both the procedures being popular. The present study has been designed to evaluate the factors predicting the success or failure of two-staged FSLO for (IAT). METHODS: 43 boys with 49 non-palpable testes underwent diagnostic laparoscopy out of which 35 underwent two-staged FSLO. Size of the testis was measured with a graduated probe in both stages. Independent variables such as age, height, testis-to-internal ring distance (T-IR), neo internal ring-to-midscrotal distance (NIR-MS), and mobility-to-contralateral ring (MCIR) were analysed. Postoperatively 34 IATs were followed up clinically as well as ultrasonologically after 6 months, to see for the size, position, and vascularity. Based on this, the patients were divided into two groups, Group A (successful) and Group B (Failed). RESULTS: 24 IATs had a successful outcome (Group A) and 11 were failure (Group B). The overall success rate of the study was 68.6%. The difference in mean age of patients in both groups was insignificant (p = 0.89) (Fig. 1), and similarly, the difference in mean height was insignificant (p = 0.61). The difference in mean T-IR in both the groups was insignificant (1.85 versus 2.77 cm; p = 0.09) and mean NIR-MS was 5.41 cm in Group A and 5.10 cm in Group B, and the difference again was insignificant (p = 0.23). CONCLUSION: The success rate of FSLO was 68.6%. None of the above-described independent variables have any effect on the outcome of two-staged FSLO. While VILO remains the treatment of choice for IAT located at or near the ring, but IAT higher than this, two-staged FSLO gives a better chance for achieving intra-scrotal orchidopexy.

Congenital Duodenal Obstruction, Situs Inversus Totalis, and Gastric Perforation in a Neonate.

We report a rare case of incomplete congenital duodenal obstruction (Type 1 duodenal atresia) in association with situs inversus totalis presenting with gastric perforation in a neonate. The infantogram was suggestive of perforation with air under diaphragm along with dextrocardia. On exploration, a pin point perforation at fundus near lesser curvature along with situs inversus was noted. Primary closure of gastric perforation was done. Patient was then discharged on full breast feeds but was readmitted with intolerance to feeds and recurrent bilious vomiting. Further, upper GI contrast study revealed partial duodenal obstruction. On re-exploration, duodenal web with central aperture was seen and duodeno-duodenostomy was done.

Mesenteric Cyst in Association with Type-II Jejunoileal Atresia.

A rare case of type-II jejunoileal atresia with mesenteric cyst in a neonate is being reported here with a brief review of literature.

Transanal impalement of double J steel bar with colonic and jejunal injury: A unique pediatric case report.

Pediatric transanal impalement injuries are relatively uncommon and most are attributed to accidental fall on offending objects, sexual assault or blunt trauma. There may be difficulty in recognizing or properly treating such injuries because their severity may not be reflected externally. Evaluation of suspected rectal impalement injury involves careful history and physical examination and proper investigation. There are very few reports on pediatric perianal impalement with associated visceral injuries. We report a case of assault transanal impalement injury associated with mesenteric tear and jejunal perforation leading to devitalization of proximal jejunum in a 2 year male child and relevant literatures were reviewed. To the best of our knowledge, such dual proximal and distal gastrointestinal injury in such a small child has not been reported in any of the English literature so far.

Association of BLM and BRCA1 during Telomere Maintenance in ALT Cells.

Fifteen percent of tumors utilize recombination-based alternative lengthening of telomeres (ALT) to maintain telomeres. The mechanisms underlying ALT are unclear but involve several proteins involved in homologous recombination including the BLM helicase, mutated in Bloom's syndrome, and the BRCA1 tumor suppressor. Cells deficient in either BLM or BRCA1 have phenotypes consistent with telomere dysfunction. Although BLM associates with numerous DNA damage repair proteins including BRCA1 during DNA repair, the functional consequences of BLM-BRCA1 association in telomere maintenance are not completely understood. Our earlier work showed the involvement of BRCA1 in different mechanisms of ALT, and telomere shortening upon loss of BLM in ALT cells. In order to delineate their roles in telomere maintenance, we studied their association in telomere metabolism in cells using ALT. This work shows that BLM and BRCA1 co-localize with RAD50 at telomeres during S- and G2-phases of the cell cycle in immortalized human cells using ALT but not in cells using telomerase to maintain telomeres. Co-immunoprecipitation of BRCA1 and BLM is enhanced in ALT cells at G2. Furthermore, BRCA1 and BLM interact with RAD50 predominantly in S- and G2-phases, respectively. Biochemical assays demonstrate that full-length BRCA1 increases the unwinding rate of BLM three-fold in assays using a DNA substrate that models a forked structure composed of telomeric repeats. Our results suggest that BRCA1 participates in ALT through its interactions with RAD50 and BLM.

WRN loss induces switching of telomerase-independent mechanisms of telomere elongation.

Telomere maintenance can occur in the presence of telomerase or in its absence, termed alternative lengthening of telomeres (ALT). ALT adds telomere repeats using recombination-based processes and DNA repair proteins that function in homologous recombination. Our previous work reported that the RecQ-like BLM helicase is required for ALT and that it unwinds telomeric substrates in vitro. WRN is also a RecQ-like helicase that shares many biochemical functions with BLM. WRN interacts with BLM, unwinds telomeric substrates, and co-localizes to ALT-associated PML bodies (APBs), suggesting that it may also be required for ALT processes. Using long-term siRNA knockdown of WRN in three ALT cell lines, we show that some, but not all, cell lines require WRN for telomere maintenance. VA-13 cells require WRN to prevent telomere loss and for the formation of APBs; Saos-2 cells do not. A third ALT cell line, U-2 OS, requires WRN for APB formation, however WRN loss results in p53-mediated apoptosis. In the absence of WRN and p53, U-2 OS cells undergo telomere loss for an intermediate number of population doublings (50-70), at which point they maintain telomere length even with the continued loss of WRN. WRN and the tumor suppressor BRCA1 co-localize to APBs in VA-13 and U-2 OS, but not in Saos-2 cells. WRN loss in U-2 OS is associated with a loss of BRCA1 from APBs. While the loss of WRN significantly increases telomere sister chromatid exchanges (T-SCE) in these three ALT cell lines, loss of both BRCA1 and WRN does not significantly alter T-SCE. This work demonstrates that ALT cell lines use different telomerase-independent maintenance mechanisms that variably require the WRN helicase and that some cells can switch from one mechanism to another that permits telomere elongation in the absence of WRN. Our data suggest that BRCA1 localization may define these mechanisms.

Predictive factors for successful vessel-intact laparoscopic orchiopexy for intra-abdominal testes.

OBJECTIVE: To identify the predictive factors for successful vessel-intact laparoscopic orchiopexy (VILO) for nonpalpable intra-abdominal testes (NPIT). MATERIALS AND METHODS: 25 boys with 28 NPITs within 2 cm of the internal ring underwent VILO. They were divided into two groups based upon outcome, for statistical comparison. Group A (successful VILO): patients with testes pexed in scrotum during surgery, and maintained viability and scrotal position of testes at 3-month & 6-month postoperative follow up. Group B: failed VILO. RESULTS: Intrascrotal fixation at VILO was achievable for 17/28 NPITs. Postoperative follow up and final outcome data were available for 25/28 NPITs, of which 14 were successful (A) while 11 had failed VILO (B). The mean age of patients in group A differed significantly from that of patients in group B (4.16 years versus 6.64 years; p = 0.035). The mean testis-to-internal ring distance was 0.50 cm for group A and 1.05 cm for group B, but this was not statistically significant (p = 0.141). There was statistically a highly significant difference (p = 0.002) with respect to the mean internal ring-to-midscrotum distances in groups A and B: 5.56 cm and 7.05 cm, respectively. A scatter-plot of age or height against internal ring-to-midscrotum distance showed a fairly linear relationship. CONCLUSIONS: Age or height of the patient at surgery is an independent factor predicting the success of VILO for intra-abdominal testis. The internal ring-to-midscrotum distance increases with age/height, resulting in increased testis-to-midscrotum distance and higher failure rate of VILO in older children.

Collaborating functions of BLM and DNA topoisomerase I in regulating human rDNA transcription.

Bloom's syndrome (BS) is an inherited disorder caused by loss of function of the recQ-like BLM helicase. It is characterized clinically by severe growth retardation and cancer predisposition. BLM localizes to PML nuclear bodies and to the nucleolus; its deficiency results in increased intra- and inter-chromosomal recombination, including hyper-recombination of rDNA repeats. Our previous work has shown that BLM facilitates RNA polymerase I-mediated rRNA transcription in the nucleolus (Grierson et al., 2012 [18]). This study uses protein co-immunoprecipitation and in vitro transcription/translation (IVTT) to identify a direct interaction of DNA topoisomerase I with the C-terminus of BLM in the nucleolus. In vitro helicase assays demonstrate that DNA topoisomerase I stimulates BLM helicase activity on a nucleolar-relevant RNA:DNA hybrid, but has an insignificant effect on BLM helicase activity on a control DNA:DNA duplex substrate. Reciprocally, BLM enhances the DNA relaxation activity of DNA topoisomerase I on supercoiled DNA substrates. Our study suggests that BLM and DNA topoisomerase I function coordinately to modulate RNA:DNA hybrid formation as well as relaxation of DNA supercoils in the context of nucleolar transcription.

Portal teratoma causing obstructive jaundice in children: a rarity.

Teratoma in children is a common entity, usually occurring both in gonadal and extragonadal sites. Common extragonadal sites for teratoma in children are the sacrococcygeal region, retroperitoneum, and mediastinum. Various unusual extragonadal sites have been reported. However, teratoma in the hepatoduodenal ligament is a very rare occurrence. We herein report a case of a mature teratoma in the hepatoduodenal ligament in an 11-year-old child presenting with obstructive jaundice along with its surgical management and review of the literature.

BLM helicase facilitates RNA polymerase I-mediated ribosomal RNA transcription.

Bloom's syndrome (BS) is an autosomal recessive disorder that is invariably characterized by severe growth retardation and cancer predisposition. The Bloom's syndrome helicase (BLM), mutations of which lead to BS, localizes to promyelocytic leukemia protein bodies and to the nucleolus of the cell, the site of RNA polymerase I-mediated ribosomal RNA (rRNA) transcription. rRNA transcription is fundamental for ribosome biogenesis and therefore protein synthesis, cellular growth and proliferation; its inhibition limits cellular growth and proliferation as well as bodily growth. We report that nucleolar BLM facilitates RNA polymerase I-mediated rRNA transcription. Immunofluorescence studies demonstrate the dependance of BLM nucleolar localization upon ongoing RNA polymerase I-mediated rRNA transcription. In vivo protein co-immunoprecipitation demonstrates that BLM interacts with RPA194, a subunit of RNA polymerase I. (3)H-uridine pulse-chase assays demonstrate that BLM expression is required for efficient rRNA transcription. In vitro helicase assays demonstrate that BLM unwinds GC-rich rDNA-like substrates that form in the nucleolus and normally inhibit progression of the RNA polymerase I transcription complex. These studies suggest that nucleolar BLM modulates rDNA structures in association with RNA polymerase I to facilitate RNA polymerase I-mediated rRNA transcription. Given the intricate relationship between rDNA metabolism and growth, our data may help in understanding the etiology of proportional dwarfism in BS.