INTRODUCTION

Neurofibromatosis type 1 (NF1) is an autosomal dominantly inherited condition seen in one of 4000 live births, predisposing to peripheral and central neurofibromas. Spinal tumors are seen in 40% of cases with NF1 and only 2% will develop symptoms, and among those who develop symptoms where 33% showed intradural extramedullary location. Thoracic spinal dumbbell neurofibroma is even rarer, and cases that extend to obliterate the posterior mediastinum even more so, with the case presented being the largest in size documented to date.

A 34-year-old female presented since childhood clinical findings consistent with Neurofibromatosis Type I: generalized cafe-au-lait macules, axillary freckling, cutaneous neurofibromas, two iris Lisch nodules identified via slit lamp examination, and anterolateral bowing of the right tibia, and no known parental history of Neurofibromatosis Type I. Prior to admission, the patient presented with progressive loss of motor strength of the lower extremities, and progressive dyspnea. Work-up revealed a Thoracic Intradural Extramedullary Neurofibroma extending to the Right Posterior Mediastinum measuring 15.3 cm x 12.9 cm x 9.7 cm in the thoracic cavity compressing the right lung and bronchus. An extensive two stage surgery was contemplated involving an initial resection of the Intradural mass, with spine instrumentation for support, and subsequent resection of the mediastinal extension. However, complications from the compressing tumor: complete cord transection syndrome causing spinal autonomic dysfunction, lung and airway compromise causing prolonged intubation and difficulty in weaning from mechanical ventilatory support, extensive thrombus formation in the right jugular vein, and nosocomial infections all created compounding difficulties for the surgical technique and anesthetic plan.

Cornerstone management for dumbbell spinal neurofibromas involves their total removal. The best results are obtained in patients showing minimal neurological deficits during the preoperative period. However, little improvement may be expected from patients who develop complete transection syndrome during the postoperative period. Concurrent medical management to prepare the patients are equally important. The multi-subspecialty approach required in managing these cases entails a good balance between the disability before the surgery, anticipated outcomes, and quality of life of the patients.

OBJECTIVE: To summarize the gene therapy strategies for neurofibromatosis type 1 (NF1) and related research progress. METHODS: The recent literature on gene therapy for NF1 at home and abroad was reviewed. The structure and function of the NF1 gene and its mutations were analyzed, and the current status as well as future prospects of the transgenic therapy and gene editing strategies were summarized. RESULTS: NF1 is an autosomal dominantly inherited tumor predisposition syndrome caused by mutations in the NF1 tumor suppressor gene, which impair the function of the neurofibromin and lead to the disease. It has complex clinical manifestations and is not yet curable. Gene therapy strategies for NF1 are still in the research and development stage. Existing studies on the transgenic therapy for NF1 have mainly focused on the construction and expression of the GTPase-activating protein-related domain in cells that lack of functional neurofibromin, confirming the feasibility of the transgenic therapy for NF1. Future research may focus on split adeno-associated virus (AAV) gene delivery, oversized AAV gene delivery, and the development of new vectors for targeted delivery of full-length NF1 cDNA. In addition, the gene editing tools of the new generation have great potential to treat monogenic genetic diseases such as NF1, but need to be further validated in terms of efficiency and safety. CONCLUSION Gene therapy, including both the transgenic therapy and gene editing, is expected to become an important new therapeutic approach for NF1 patients.
Humans ; Neurofibromatosis 1/pathology* ; Neurofibromin 1/metabolism* ; GTPase-Activating Proteins ; Mutation ; Genetic Predisposition to Disease ; Genetic Therapy

BACKGROUND

Newborns screened positive for Galactosemia through Expanded Newborn Screening (ENBS) with borderline levels undergo lactose challenge that requires interruption of breastfeeding temporarily then shifting to soy-based formula.

To determine the percentage of Classical Galactosemia (CGal), Non-classical Galactosemia (NCGal), probable mild variant form, and negative Galactosemia among newborns screened positive for Galactosemia who underwent lactose challenge.

This is a retrospective study. NBS records were reviewed and data were collected from January 2015 to December 2020.

Out of the 117 newborns screened positive for Galactosemia, 58 underwent lactose challenge. Majority were male, term with a birth weight of 2500-4000g and received a final disposition in 4-6 months. Fifteen patients underwent 1-week lactose challenge wherein six reached a resolution on first challenge. Majority, 35 (60.3%) were negative for Galactosemia, six (10.3%) probable mild variant Galactosemia, three (5.2%) NCGal, and no CGal were observed. Fourteen suspected cases (24.1%) are pending final disposition.

This study describes the demographics of newborns flagged for Galactosemia who underwent lactose challenge. A 1-week lactose challenge may be recommended to further detect patients who are negative for Galactosemia.

OBJECTIVE

Our study aimed to determine the clinical profile and pulmonary function of pediatric patients with Duchenne Muscular Dystrophy (DMD). We also characterized the stages of progression of the disease and determined their potential association with spirometry variables.

In this cross-sectional study, we used data obtained from a review of medical records of all pediatric patients (0-18 years old) with DMD seen in a multidisciplinary neuromuscular clinic of a tertiary government hospital from August 2018 until March 2020.

Included were 30 patients subdivided into groups according to the stage of disease progression. Overweight (26.7%), obesity (20%), and scoliosis (26.7%) were common among non-ambulatory patients. Only one late ambulatory patient had evidence of ineffective airway clearance. Symptoms of sleep-disordered breathing, particularly snoring (66.7%) and apnea (6.7%), were common across all disease stages. All patients had normal peripheral oxygen saturation on room air. The mean peak expiratory flow rate was 215.6 (±84) L/min. The mean Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), and FEV1/FVC were 66.2% (±23.7), 67.7% (±23.8), and 97.5 (±3.2), respectively. Among patients with polysomnography results, the average apnea-hypopnea index (AHI) per hour was 3 (±1.6). When patients were compared according to their stage disease progression, however, no significant differences exist.

This is the first study on the pulmonary function of Filipino pediatric patients with DMD. Spirometry patterns characteristic of restrictive lung disease were observed. Prospective studies may help identify respiratory variables that significantly correlate with pulmonary function.

Disorders of sex development (DSD) are characterized by atypical development of chromosomal, gonadal, or phenotypic sex. 45X,46XY mosaicism is a type of sex chromosome DSD which presents with a wide heterogeneity of manifestations. We report the case of a 13-year-old phenotypically female who presented with clitoromegaly at puberty. Testosterone level was elevated on serology. Out of the 50 cells examined, 43 cells had Monosomy X while 7 cells had a normal male karyotype. She was managed by a multidisciplinary team. Due to the presence of Y chromosome, the solid nodular structure seen on the right gonad in magnetic resonance imaging and the pain caused by the phallus, Laparoscopic bilateral gonadectomy, salpingectomy and clitoroplasty were done after a shared decision making. Histopathology revealed Gonadoblastoma and Germ cell neoplasia-in-situ of the right gonad justifying timely removal. She was then maintained on estrogen for induction of secondary sexual characteristics.

Junctional Epidermolysis Bullosa (JEB) is a rare inherited blistering disorder characterized by extreme skin fragility. It is associated with COL17A1 mutation that is critical for dermoepidermal adhesion. Effective management in resource-limited settings is challenging and focuses on wound care and trauma prevention to prevent complications and improve quality of life.

A 27-year-old Filipino female presented with recurrent blisters and erosions since infancy, accompanied by diffuse alopecia and anonychia of the toenails. On physical examination, she presented with multiple, well-defined, erythematous tense vesicles and bullae on the trunk, upper and lower extremities which were triggered by minor trauma to the skin. Skin punch biopsy was done revealing a subepidermal blistering dermatosis while direct immunofluorescence (DIF) and Enzyme-Linked Immunosorbent Assay (ELISA) tests for BP180, BP230, and type VII collagen were negative. Genetic testing was done and revealed compound heterozygous mutations in the COL17A1 gene, consistent with JEB. She was managed with non-adhesive dressings, sterile aspiration of blisters, and nutritional support. Despite the severity of her condition, the patient experienced significant improvement in wound healing and quality of life through meticulous wound care, trauma prevention and nutritional support.

This case highlights the unusual case of a 27-year-old Filipino female with JEB who has survived into adulthood, a rarity given the typically poor prognosis associated with severe forms of the disease.

Dystrophic epidermolysis bullosa (DEB) is characterized by blisters that heal with scarring and milia formation, including nail dystrophy, with an incidence of 2.1 per million live births. DEB is derived from defects of the anchoring fibril which results in sublamina densa separation.

We report a one-month old female who presented with vesicles and erosions on bilateral feet at birth. New vesicles and bullae were noted on other areas of the body such as the scalp, ears, anterior trunk, gluteal area, and extremities which spontaneously ruptured leading to erosions and crusts. Nails were thick and yellowish black. Consult was done at a clinic and was given unrecalled antibiotic, antihistamine, and cream for one week. There was no noted improvement hence she was brought to another clinic, diagnosed as staphylococcal scalded skin syndrome, advised admission and subsequently referred to dermatology service. After clinical assessment, findings of cell poor subepidermal blister on histology, linear C3 on DIF, and positive collagen 7 on ELISA, patient was managed as a case of dystrophic epidermolysis bullosa.

Epidermolysis bullosa is an inherited genetic disease with mutation in COL7A1 gene manifesting as vesicles and bullae on trauma prone areas. The diagnosis is based on clinical, histopathology, immunofluorescence, antigen studies, and electron microscopy. Uniquely, immunofluorescence revealed strong linear deposition of C3 at the basement membrane zone which is more suggestive of bullous pemphigoid than epidermolysis bullosa. This case highlights the importance of early diagnosis and proper management of the disease to limit unnecessary intervention.

Introduction: Epidermolysis Bullosa Pruriginosa (EBP) is a rare subtype of the inherited Dystrophic ~ Epidermolysis Bullosa spectrum of diseases and results from a gene mutation in COL7AL Though predominantly an autosomal dominant disease, autosomal recessive and even sporadic have been reported. Case Summary: Case Summary:We report a case of a 12-year-old Filipino male presenting with a chronic history of numerous scratching-induced blisters predominantly distributed on the extensor aspect of his arms and legs without concomitant oral lesions, nail dystrophy, or hair findings, and without a family history of similar lesions. Histopathologic assessment, Direct Immunofluorescence (DIF), and Indirect Immunofiuorescence (IIF) showed a subepidermal split with scant inflammatory infiltrates, no immunofluorescence, and absent userrated linear immunofluorescence at the dermal-side of the Salt Split Skin slide, respectively, which were all consistent with EBP. Enzyme-Linked Immunosorbent Assay (ELISA) for Anti-Collagen VII antibodies was slightly elevated, which may suggest an alternative diagnosis of Epidermolysis Bullosa Acquisita (EBA). This slight elevation may be due to the mutated Collagen Vil protein becoming antigenic and therefore provoking an immune response. To conclusively distinguish EBP from EBA, a COL7AI gene mutation analysis was recommended. With a diagnosis of EBP cannot totally rule out EBA, the patient was initially managed with dapsone monotherapy, counseled regarding behavioral modification to reduce scratching and trauma, advised wound care and close monitoring for the development of oropharyngeal lesions, and recommended for COL7A1 genetic mutation analysis. Conclusion This report demonstrates a case of EBP with elevated Anti-Collagen VII antibodies. The diistinction between EBP and EBA is important because this changes the management: EBP is largely supportive, while EBA may benefit from immunosuppressive therapy.
Epidermolysis Bullosa Pruriginosa ; Enzyme-Linked Immunosorbent Assay ; Epidermolysis Bullosa Acquisita

Humans ; Muscular Dystrophy, Duchenne/epidemiology* ; Prevalence ; Myocardium

Virtually all of the dietary potassium intake is absorbed in the intestine, over 90% of which is excreted by the kidneys regarded as the most important organ of potassium excretion in the body. The renal excretion of potassium results primarily from the secretion of potassium by the principal cells in the aldosterone-sensitive distal nephron (ASDN), which is coupled to the reabsorption of Na⁺ by the epithelial Na⁺ channel (ENaC) located at the apical membrane of principal cells. When Na⁺ is transferred from the lumen into the cell by ENaC, the negativity in the lumen is relatively increased. K⁺ efflux, H⁺ efflux, and Cl^- influx are the 3 pathways that respond to Na⁺ influx, that is, all these 3 pathways are coupled to Na⁺ influx. In general, Na⁺ influx is equal to the sum of K⁺ efflux, H⁺ efflux, and Cl^- influx. Therefore, any alteration in Na⁺ influx, H⁺ efflux, or Cl^- influx can affect K⁺ efflux, thereby affecting the renal K⁺ excretion. Firstly, Na⁺ influx is affected by the expression level of ENaC, which is mainly regulated by the aldosterone-mineralocorticoid receptor (MR) pathway. ENaC gain-of-function mutations (Liddle syndrome, also known as pseudohyperaldosteronism), MR gain-of-function mutations (Geller syndrome), increased aldosterone levels (primary/secondary hyperaldosteronism), and increased cortisol (Cushing syndrome) or deoxycorticosterone (hypercortisolism) which also activate MR, can lead to up-regulation of ENaC expression, and increased Na⁺ reabsorption, K⁺ excretion, as well as H⁺ excretion, clinically manifested as hypertension, hypokalemia and alkalosis. Conversely, ENaC inactivating mutations (pseudohypoaldosteronism type 1b), MR inactivating mutations (pseudohypoaldosteronism type 1a), or decreased aldosterone levels (hypoaldosteronism) can cause decreased reabsorption of Na⁺ and decreased excretion of both K⁺ and H⁺, clinically manifested as hypotension, hyperkalemia, and acidosis. The ENaC inhibitors amiloride and Triamterene can cause manifestations resembling pseudohypoaldosteronism type 1b; MR antagonist spironolactone causes manifestations similar to pseudohypoaldosteronism type 1a. Secondly, Na⁺ influx is regulated by the distal delivery of water and sodium. Therefore, when loss-of-function mutations in Na⁺-K⁺-2Cl^- cotransporter (NKCC) expressed in the thick ascending limb of the loop and in Na⁺-Cl^- cotransporter (NCC) expressed in the distal convoluted tubule (Bartter syndrome and Gitelman syndrome, respectively) occur, the distal delivery of water and sodium increases, followed by an increase in the reabsorption of Na⁺ by ENaC at the collecting duct, as well as increased excretion of K⁺ and H⁺, clinically manifested as hypokalemia and alkalosis. Loop diuretics acting as NKCC inhibitors and thiazide diuretics acting as NCC inhibitors can cause manifestations resembling Bartter syndrome and Gitelman syndrome, respectively. Conversely, when the distal delivery of water and sodium is reduced (e.g., Gordon syndrome, also known as pseudohypoaldosteronism type 2), it is manifested as hypertension, hyperkalemia, and acidosis. Finally, when the distal delivery of non-chloride anions increases (e.g., proximal renal tubular acidosis and congenital chloride-losing diarrhea), the influx of Cl^- in the collecting duct decreases; or when the excretion of hydrogen ions by collecting duct intercalated cells is impaired (e.g., distal renal tubular acidosis), the efflux of H⁺ decreases. Both above conditions can lead to increased K⁺ secretion and hypokalemia. In this review, we focus on the regulatory mechanisms of renal potassium excretion and the corresponding diseases arising from dysregulation.
Humans ; Bartter Syndrome/metabolism* ; Pseudohypoaldosteronism/metabolism* ; Potassium/metabolism* ; Aldosterone/metabolism* ; Hypokalemia/metabolism* ; Gitelman Syndrome/metabolism* ; Hyperkalemia/metabolism* ; Clinical Relevance ; Epithelial Sodium Channels/metabolism* ; Kidney Tubules, Distal/metabolism* ; Sodium/metabolism* ; Hypertension ; Alkalosis/metabolism* ; Water/metabolism* ; Kidney/metabolism*