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Stroup BM, Li X, Ho S, Zhouyao H, Chen Y, Ani S, Dawson B, Jin Z, Marom R, Jiang MM, Lorenzo I, Rosen D, Lanza D, Aceves N, Koh S, Seavitt JR, Heaney JD, Lee B, Burrage LC. Delayed skeletal development and IGF-1 deficiency in a mouse model of lysinuric protein intolerance. Dis Model Mech 2023; 16:dmm050118. [PMID: 37486182 PMCID: PMC10445726 DOI: 10.1242/dmm.050118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023] Open
Abstract
SLC7A7 deficiency, or lysinuric protein intolerance (LPI), causes loss of function of the y+LAT1 transporter critical for efflux of arginine, lysine and ornithine in certain cells. LPI is characterized by urea cycle dysfunction, renal disease, immune dysregulation, growth failure, delayed bone age and osteoporosis. We previously reported that Slc7a7 knockout mice (C57BL/6×129/SvEv F2) recapitulate LPI phenotypes, including growth failure. Our main objective in this study was to characterize the skeletal phenotype in these mice. Compared to wild-type littermates, juvenile Slc7a7 knockout mice demonstrated 70% lower body weights, 87% lower plasma IGF-1 concentrations and delayed skeletal development. Because poor survival prevents evaluation of mature knockout mice, we generated a conditional Slc7a7 deletion in mature osteoblasts or mesenchymal cells of the osteo-chondroprogenitor lineage, but no differences in bone architecture were observed. Overall, global Slc7a7 deficiency caused growth failure with low plasma IGF-1 concentrations and delayed skeletal development, but Slc7a7 deficiency in the osteoblastic lineage was not a major contributor to these phenotypes. Future studies utilizing additional tissue-specific Slc7a7 knockout models may help dissect cell-autonomous and non-cell-autonomous mechanisms underlying phenotypes in LPI.
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Affiliation(s)
- Bridget M. Stroup
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiaohui Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sara Ho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haonan Zhouyao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuqing Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Safa Ani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brian Dawson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zixue Jin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
| | - Ming-Ming Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Isabel Lorenzo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel Rosen
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nathalie Aceves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sara Koh
- Rice University, Houston, TX 77005, USA
| | - John R. Seavitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jason D. Heaney
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
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Avci Durmusalioglu E, Isik E, Ayyildiz Emecen D, Goksen D, Ozen S, Onay H, Kose M, Atik T, Darcan S, Cogulu O, Ozkinay F. The utility of reverse phenotyping: a case of lysinuric protein intolerance presented with childhood osteoporosis. J Pediatr Endocrinol Metab 2021; 34:957-960. [PMID: 33823103 DOI: 10.1515/jpem-2021-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 02/18/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Childhood osteoporosis is often a consequence of a chronic disease or its treatment. Lysinuric protein intolerance (LPI), a rare secondary cause of the osteoporosis, is an autosomal recessive disorder with clinical features ranging from minimal protein intolerance to severe multisystemic involvement. We report a case diagnosed to have LPI using a Next Generation Sequencing (NGS) panel and evaluate the utility of reverse phenotyping. CASE PRESENTATION A fifteen-year-old-boy with an initial diagnosis of osteogenesis imperfecta, was referred due to a number of atypical findings accompanying to osteoporosis such as splenomegaly and bicytopenia. A NGS panel (TruSight One Sequencing Panel) was performed and a novel homozygous mutation of c.257G>A (p.Gly86Glu) in the SLC7A7 gene (NM_001126106.2), responsible for LPI, was detected. The diagnosis was confirmed via reverse phenotyping. CONCLUSIONS Reverse phenotyping using a multigene panel shortens the diagnostic process.
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Affiliation(s)
- Enise Avci Durmusalioglu
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Esra Isik
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Durdugul Ayyildiz Emecen
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Damla Goksen
- Department of Pediatric Endocrinology and Diabetes, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Samim Ozen
- Department of Pediatric Endocrinology and Diabetes, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Huseyin Onay
- Department of Medical Genetics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Melis Kose
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Tahir Atik
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Sukran Darcan
- Department of Pediatric Endocrinology and Diabetes, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Ozgur Cogulu
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Ferda Ozkinay
- Pediatric Genetics Subdivision, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
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3
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Stroup BM, Marom R, Li X, Hsu CW, Chang CY, Truong LD, Dawson B, Grafe I, Chen Y, Jiang MM, Lanza D, Green JR, Sun Q, Barrish JP, Ani S, Christiansen AE, Seavitt JR, Dickinson ME, Kheradmand F, Heaney JD, Lee B, Burrage LC. A global Slc7a7 knockout mouse model demonstrates characteristic phenotypes of human lysinuric protein intolerance. Hum Mol Genet 2020; 29:2171-2184. [PMID: 32504080 PMCID: PMC7399531 DOI: 10.1093/hmg/ddaa107] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/30/2020] [Accepted: 05/19/2020] [Indexed: 12/18/2022] Open
Abstract
Lysinuric protein intolerance (LPI) is an inborn error of cationic amino acid (arginine, lysine, ornithine) transport caused by biallelic pathogenic variants in SLC7A7, which encodes the light subunit of the y+LAT1 transporter. Treatments for the complications of LPI, including growth failure, renal disease, pulmonary alveolar proteinosis, autoimmune disorders and osteoporosis, are limited. Given the early lethality of the only published global Slc7a7 knockout mouse model, a viable animal model to investigate global SLC7A7 deficiency is needed. Hence, we generated two mouse models with global Slc7a7 deficiency (Slc7a7em1Lbu/em1Lbu; Slc7a7Lbu/Lbu and Slc7a7em1(IMPC)Bay/em1(IMPC)Bay; Slc7a7Bay/Bay) using CRISPR/Cas9 technology by introducing a deletion of exons 3 and 4. Perinatal lethality was observed in Slc7a7Lbu/Lbu and Slc7a7Bay/Bay mice on the C57BL/6 and C57BL/6NJ inbred genetic backgrounds, respectively. We noted improved survival of Slc7a7Lbu/Lbu mice on the 129 Sv/Ev × C57BL/6 F2 background, but postnatal growth failure occurred. Consistent with human LPI, these Slc7a7Lbu/Lbu mice exhibited reduced plasma and increased urinary concentrations of the cationic amino acids. Histopathological assessment revealed loss of brush border and lipid vacuolation in the renal cortex of Slc7a7Lbu/Lbu mice, which combined with aminoaciduria suggests proximal tubular dysfunction. Micro-computed tomography of L4 vertebrae and skeletal radiographs showed delayed skeletal development and suggested decreased mineralization in Slc7a7Lbu/Lbu mice, respectively. In addition to delayed skeletal development and delayed development in the kidneys, the lungs and liver were observed based on histopathological assessment. Overall, our Slc7a7Lbu/Lbu mouse model on the F2 mixed background recapitulates multiple human LPI phenotypes and may be useful for future studies of LPI pathology.
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Affiliation(s)
- Bridget M Stroup
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
| | - Xiaohui Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Chih-Wei Hsu
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Cheng-Yen Chang
- Department of Medicine-Pulmonary, Baylor College of Medicine, Houston, TX 77030, USA
| | - Luan D Truong
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, USA
| | - Brian Dawson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ingo Grafe
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Division of Endocrinology, Diabetes, and Bone Diseases, Department of Medicine III, Center for Healthy Aging, University Clinic, Dresden D-01307, Germany
| | - Yuqing Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ming-Ming Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennie Rose Green
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Qin Sun
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor Genetics, Houston, TX 77021, USA
| | - J P Barrish
- Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, Houston, TX 77030, USA
| | - Safa Ani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Audrey E Christiansen
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - John R Seavitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mary E Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Farrah Kheradmand
- Department of Medicine-Pulmonary, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jason D Heaney
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Texas Children's Hospital, Houston, TX 77030, USA
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Yahyaoui R, Pérez-Frías J. Amino Acid Transport Defects in Human Inherited Metabolic Disorders. Int J Mol Sci 2019; 21:ijms21010119. [PMID: 31878022 PMCID: PMC6981491 DOI: 10.3390/ijms21010119] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/12/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023] Open
Abstract
Amino acid transporters play very important roles in nutrient uptake, neurotransmitter recycling, protein synthesis, gene expression, cell redox balance, cell signaling, and regulation of cell volume. With regard to transporters that are closely connected to metabolism, amino acid transporter-associated diseases are linked to metabolic disorders, particularly when they involve different organs, cell types, or cell compartments. To date, 65 different human solute carrier (SLC) families and more than 400 transporter genes have been identified, including 11 that are known to include amino acid transporters. This review intends to summarize and update all the conditions in which a strong association has been found between an amino acid transporter and an inherited metabolic disorder. Many of these inherited disorders have been identified in recent years. In this work, the physiological functions of amino acid transporters will be described by the inherited diseases that arise from transporter impairment. The pathogenesis, clinical phenotype, laboratory findings, diagnosis, genetics, and treatment of these disorders are also briefly described. Appropriate clinical and diagnostic characterization of the underlying molecular defect may give patients the opportunity to avail themselves of appropriate therapeutic options in the future.
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Affiliation(s)
- Raquel Yahyaoui
- Laboratory of Metabolic Disorders and Newborn Screening Center of Eastern Andalusia, Málaga Regional University Hospital, 29011 Málaga, Spain
- Grupo Endocrinología y Nutrición, Diabetes y Obesidad, Instituto de Investigación Biomédica de Málaga-IBIMA, 29010 Málaga, Spain
- Correspondence:
| | - Javier Pérez-Frías
- Grupo Multidisciplinar de Investigación Pediátrica, Instituto de Investigación Biomédica de Málaga-IBIMA, 29010 Málaga, Spain;
- Departamento de Farmacología y Pediatría, Facultad de Medicina, Universidad de Málaga, 29010 Málaga, Spain
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5
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Noguchi A, Takahashi T. Overview of symptoms and treatment for lysinuric protein intolerance. J Hum Genet 2019; 64:849-858. [PMID: 31213652 DOI: 10.1038/s10038-019-0620-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 12/30/2022]
Abstract
Lysinuric protein intolerance (LPI) is caused by dysfunction of the dibasic amino acid membrane transport owing to the functional abnormality of y+L amino acid transporter-1 (y+ LAT-1). LPI is associated with autosomal recessive inheritance and pathological variants in the responsible gene SLC7A7 are also observed. The pathophysiology of this disease had earlier been understood as a transport defect in polarized cells (e.g., intestinal or renal tubular epithelium); however, in recent years, transport defects in non-polarized cells such as lymphocytes and macrophages have also been recognized as important. Although the former can cause death, malnutrition, and urea cycle dysfunction (hyperammonemia), the latter can induce renal, pulmonary, and immune disorders. Furthermore, although therapeutic interventions can prevent hyperammonemic episodes to some extent, progression of pulmonary and renal complications cannot be prevented, thereby influencing prognosis. Such pathological conditions are currently being explored and further investigation would prove beneficial. In this study, we have summarized the basic pathology as revealed in recent years, along with the clinical aspects and genetic features.
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Affiliation(s)
- Atsuko Noguchi
- Akita University Graduate School of Medicine, Pediatrics, Akita, Akita, Japan.
| | - Tsutomu Takahashi
- Akita University Graduate School of Medicine, Pediatrics, Akita, Akita, Japan
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6
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Posey JE, Burrage LC, Miller MJ, Liu P, Hardison MT, Elsea SH, Sun Q, Yang Y, Willis AS, Schlesinger AE, Bacino CA, Lee BH. Lysinuric Protein Intolerance Presenting with Multiple Fractures. Mol Genet Metab Rep 2014; 1:176-183. [PMID: 25419514 PMCID: PMC4235665 DOI: 10.1016/j.ymgmr.2014.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Lysinuric protein intolerance (LPI) is a rare autosomal recessive inborn error of metabolism caused by mutations in SLC7A7, which encodes a component of the dibasic amino acid transporter found in intestinal and renal tubular cells. Patients typically present with vomiting, diarrhea, irritability, failure to thrive, and symptomatic hyperammonemia after protein-rich meals. Long-term complications may include pulmonary alveolar proteinosis, renal disease, and osteoporosis. We present a 5-year-old male who was followed in our skeletal dysplasia clinic for 3 years for multiple fractures, idiopathic osteoporosis, and short stature in the absence of typical features of LPI. Whole exome sequencing performed to determine the etiology of the osteoporosis and speech delay identified a nonsense mutation in SLC7A7. Chromosome microarray analysis identified a deletion involving the second allele of the same gene, and biochemical analysis supported the diagnosis of LPI. Our patient's atypical presentation underscores the importance of maintaining a high index of suspicion for LPI in patients with unexplained fractures and idiopathic osteoporosis, even in the absence of clinical symptoms of hyperammonemia after protein rich meals or other systemic features of classical LPI. This case further demonstrates the utility of whole exome sequencing in diagnosis of unusual presentations of rare disorders for which early intervention may modify the clinical course.
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Affiliation(s)
- Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Marcus J Miller
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Matthew T Hardison
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Qin Sun
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Alecia S Willis
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Alan E Schlesinger
- Department of Pediatric Radiology, Texas Children's Hospital, 6701 Fannin, Suite 470, Houston, TX, 77030, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA
| | - Brendan H Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Suite R814, Houston, TX, 77030-3411, USA ; Howard Hughes Medical Institute, Houston, TX, USA
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7
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Tanner LM, Näntö-Salonen K, Venetoklis J, Kotilainen S, Niinikoski H, Huoponen K, Simell O. Nutrient intake in lysinuric protein intolerance. J Inherit Metab Dis 2007; 30:716-21. [PMID: 17588131 DOI: 10.1007/s10545-007-0558-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2007] [Revised: 04/25/2007] [Accepted: 04/27/2007] [Indexed: 02/07/2023]
Abstract
Lysinuric protein intolerance (LPI) is a rare autosomal recessive disorder characterized by defective transport of cationic amino acids. Poor intestinal absorption and increased renal loss of arginine, ornithine and lysine lead to low plasma concentrations of these amino acids and, subsequently, to impaired urea cycle function. The patients therefore have decreased nitrogen tolerance, which may lead to hyperammonaemia after ingestion of normal amounts of dietary protein. As a protective mechanism, most patients develop strong aversion to protein-rich foods early in life. Oral supplementation with citrulline, which is absorbed normally and metabolized to arginine and ornithine, improves protein tolerance to some extent, as do sodium benzoate and sodium phenylbutyrate also used by some patients. Despite effective prevention of hyperammonaemia, the patients still consume a very restricted diet, which may be deficient in energy, essential amino acids and some vitamins and minerals. To investigate the potential nutritional problems of patients with lysinuric protein intolerance, 77 three- to four-day food records of 28 Finnish LPI patients aged 1.5-61 years were analysed. The data suggest that the patients are clearly at risk for many nutritional deficiencies, which may contribute to their symptoms. Their diet is highly deficient in calcium, vitamin D, iron and zinc. Individualized nutritional supplementation accompanied by regular monitoring of dietary intake is therefore an essential part of the treatment of LPI.
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Affiliation(s)
- L M Tanner
- Department of Pediatrics, University of Turku, Kiinamyllynkatu 4-8, 20520, Turku, Finland.
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8
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Tanner LM, Näntö-Salonen K, Niinikoski H, Jahnukainen T, Keskinen P, Saha H, Kananen K, Helanterä A, Metso M, Linnanvuo M, Huoponen K, Simell O. Nephropathy advancing to end-stage renal disease: a novel complication of lysinuric protein intolerance. J Pediatr 2007; 150:631-4, 634.e1. [PMID: 17517249 DOI: 10.1016/j.jpeds.2007.01.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 11/28/2006] [Accepted: 01/31/2007] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To analyze systemically the prevalence of renal involvement in a cohort of Finnish patients with lysinuric protein intolerance (LPI) and to describe the course and outcome of end-stage renal disease in 4 patients. STUDY DESIGN The clinical information in a cohort of 39 Finnish patients with LPI was analyzed retrospectively. RESULTS Proteinuria was observed in 74% of the patients and hematuria was observed in 38% of the patients during follow-up. Elevated blood pressure was diagnosed in 36% of the patients. Mean serum creatinine concentration increased in 38% of the patients, and cystatin C concentration increased in 59% of the patients. Four patients required dialysis, and severe anemia with poor response to erythropoietin and iron supplementation also developed in these patients. CONCLUSIONS Our findings suggest that renal function of patients with LPI needs to be carefully monitored, and hypertension and hyperlipidemia should be treated effectively. Special attention also should be paid to the prevention of osteoporosis and carnitine deficiency in the patients with end-stage renal disease associated with LPI. The primary disease does not prohibit treatment by dialysis and renal transplantation.
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Affiliation(s)
- Laura M Tanner
- Department of Pediatrics, University of Turku, Turku, Finland.
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9
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Tanner LM, Näntö-Salonen K, Niinikoski H, Huoponen K, Simell O. Long-term oral lysine supplementation in lysinuric protein intolerance. Metabolism 2007; 56:185-9. [PMID: 17224331 DOI: 10.1016/j.metabol.2006.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 09/07/2006] [Indexed: 02/04/2023]
Abstract
In lysinuric protein intolerance (LPI), defective transport of cationic amino acids at the basolateral membrane of the polar epithelial cells in the intestine and renal tubules leads to decreased intestinal absorption and excessive renal loss of lysine, arginine, and ornithine. Citrulline supplementation partially restores the function of the urea cycle that is impaired by deficiency of arginine and ornithine, but does not correct the chronic lysine deficiency. Previous attempts to supplement lysine orally have been hindered by profuse diarrhea, probably caused by excess lysine remaining unabsorbed in the gut. However, individually adjusted minute doses of L-lysine hydrochloride at mealtimes are tolerated well, but the long-term benefits of this therapy remain unknown. The aim of the study was to investigate the long-term benefits and possible adverse effects of oral lysine supplementation in patients with LPI. Supplementation of meals with low doses of oral lysine improved fasting plasma lysine concentrations in 27 Finnish patients with LPI without causing hyperammonemia or other recognizable side effects during 12 months of follow-up. In conclusion, low-dose oral lysine supplementation is potentially beneficial to patients with LPI and can be started safely at an early age.
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Affiliation(s)
- Laura M Tanner
- Department of Pediatrics, University of Turku, 20520 Turku, Finland.
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10
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Lukkarinen M, Näntö-Salonen K, Pulkki K, Aalto M, Simell O. Oral supplementation corrects plasma lysine concentrations in lysinuric protein intolerance. Metabolism 2003; 52:935-8. [PMID: 12870174 DOI: 10.1016/s0026-0495(03)00089-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In lysinuric protein intolerance (LPI), intestinal absorption and renal tubular reabsorption of arginine, ornithine, and lysine are impaired due to a defective cationic amino acid transporter. Deficiency of arginine and ornithine restricts the function of the urea cycle, leading to hyperammonemia after protein load, and to strong protein aversion. Mealtime supplements of citrulline, another urea cycle intermediate that uses other transport mechanisms, prevent postprandial hyperammonemia and improve protein tolerance. Deficiency of lysine, an essential amino acid, most probably also contributes to the symptoms of LPI. We investigated possibilities to improve the availability of lysine for tissues by increasing plasma lysine concentration. Six patients with LPI were started on short-term oral lysine supplementation that was administered with their regular citrulline doses and standard low-protein meals. L-Lysine in consecutive doses of 0.55 and 1.1 mmol/kg caused profuse diarrhea in first 3 patients. To avoid gastrointestinal side effects, the 3 other patients were started on smaller lysine supplements of only 0.05 mmol/kg per dose, given 3 times daily for 3 days. All pre- and postprandial plasma lysine concentrations remained within normal range in 2 of the 3 patients studied. Even after the larger doses, no significant effects on the urea cycle were seen. We conclude that low-dose oral lysine supplementation normalizes plasma lysine concentration in patients with LPI, and is safe and well tolerated at least in short-term use.
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11
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Kauffman RP, Overton TH, Shiflett M, Jennings JC. Osteoporosis in children and adolescent girls: case report of idiopathic juvenile osteoporosis and review of the literature. Obstet Gynecol Surv 2001; 56:492-504. [PMID: 11496161 DOI: 10.1097/00006254-200108000-00023] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
UNLABELLED The diagnosis and treatment of osteoporosis is an important aspect of gynecologic training and practice. Idiopathic juvenile osteoporosis (IJO) is a rare disease of children and adolescents that resolves after the onset of puberty. A case report is presented and current methods of diagnosis and treatment of IJO are discussed as well as the differential diagnosis. A MEDLINE search was performed of the following terms: idiopathic juvenile osteoporosis, pediatric osteoporosis, adolescent osteoporosis, bisphosphonates pediatric adolescent, and pregnancy osteoporosis, and references from bibliographies of selected papers were used as well. All papers in English, French, and German are considered in this review. There were 114 papers selected as relevant to the topic. Data relevant to the diagnosis, pathogenesis, methods of imaging, laboratory evaluation, differential diagnosis, and treatment of IJO are presented. IJO is a diagnosis of exclusion in the pediatric and adolescent patient with osteoporosis. Although bone density gradually improves after the onset of puberty, treatment of currently affected children and adolescents involves activity restriction, calcium, vitamin D, and bisphosphonate therapy. Future reproductive concerns are discussed and areas requiring additional study are reviewed. TARGET AUDIENCE Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES After completion of this article, the reader will be able to describe the condition idiopathic juvenile osteoporosis, compare the clinical features of this condition to other similar conditions, outline the diagnostic workup of a child with this condition, and list the potential therapeutic options for a patient with idiopathic juvenile osteoporosis.
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Affiliation(s)
- R P Kauffman
- Department of Obstetrics and Gynecology, Texas Tech University Health Sciences Center, Amarillo, 79106, USA.
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Parsons H, Snyder F, Bowen T, Klassen J, Pinto A. Immune complex disease consistent with systemic lupus erythematosus in a patient with lysinuric protein intolerance. J Inherit Metab Dis 1996; 19:627-34. [PMID: 8892019 DOI: 10.1007/bf01799838] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- H Parsons
- Department of Pediatrics, University of Calgary, Alberta, Canada
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Parto K, Svedström E, Majurin ML, Härkönen R, Simell O. Pulmonary manifestations in lysinuric protein intolerance. Chest 1993; 104:1176-82. [PMID: 8404187 DOI: 10.1378/chest.104.4.1176] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
STUDY OBJECTIVES To evaluate the pulmonary manifestations and the course of acute respiratory insufficiency associated with lysinuric protein intolerance (LPI). DESIGN Retrospective review of clinical data and chest radiographs (total 225) obtained during the lifetime follow-up of 31 LPI patients. About half of the 25 patients without respiratory symptoms underwent high-resolution computed tomography (HRCT) of the lungs, radionuclide perfusion imaging, whole body plethysmography, and diffusing capacity measurements. PATIENTS Thirty-one Finnish patients with LPI. RESULTS During the follow-up period, four children with LPI died in respiratory insufficiency, 1 adult had an episode of respiratory insufficiency, and another had chronic symptoms, whereas 25 patients remained symptom-free. The radiologic findings in acute progressive respiratory insufficiency were uniform: at first, reticulonodular interstitial densities and, later on, progressive airspace disease. At autopsy, three patients showed pulmonary alveolar proteinosis and one had pulmonary hemorrhage and cholesterol granulomas. One adult had reversible respiratory insufficiency with signs of bronchiolitis obliterans, another adult had recurrent episodes of chest pain, dyspnea, and hypoxia. Of the symptom-free patients, one third (8 of 25) had signs suggestive of pulmonary fibrosis evidenced on chest radiographs and two thirds (8 of 14) had signs evidenced by HRCT films. Most symptom-free patients showed mild abnormalities either in perfusion imaging (9 of 12) or in function tests (8 of 12). CONCLUSION In childhood, patients with LPI are highly predisposed to develop pulmonary hemorrhages and alveolar proteinosis. Interstitial lung densities may precede the acute phase. Most adult LPI patients show radiologic signs of interstitial lung disease but only a few show clinical impairment.
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Affiliation(s)
- K Parto
- Department of Pediatric, Turku University Hospital, Finland
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