title: Body composition in patients with classical homocystinuria: body mass relates to homocysteine and choline metabolism.
abstract: BACKGROUND
  Classical homocystinuria is a rare genetic disease caused by cystathionine β-synthase deficiency, resulting in homocysteine accumulation. Growing evidence suggests that reduced fat mass in patients with classical homocystinuria may be associated with alterations in choline and homocysteine pathways. This study aimed to evaluate the body composition of patients with classical homocystinuria, identifying changes in body fat percentage and correlating findings with biochemical markers of homocysteine and choline pathways, lipoprotein levels and bone mineral density (BMD) T-scores.
  
  
  METHODS
  Nine patients with classical homocystinuria were included in the study. Levels of homocysteine, methionine, cysteine, choline, betaine, dimethylglycine and ethanolamine were determined. Body composition was assessed by bioelectrical impedance analysis (BIA) in patients and in 18 controls. Data on the last BMD measurement and lipoprotein profile were obtained from medical records.
  
  
  RESULTS
  Of 9 patients, 4 (44%) had a low body fat percentage, but no statistically significant differences were found between patients and controls. Homocysteine and methionine levels were negatively correlated with body mass index (BMI), while cysteine showed a positive correlation with BMI (p<0.05). There was a trend between total choline levels and body fat percentage (r=0.439, p=0.07). HDL cholesterol correlated with choline and ethanolamine levels (r=0.757, p=0.049; r=0.847, p=0.016, respectively), and total cholesterol also correlated with choline levels (r=0.775, p=0.041). There was no association between BMD T-scores and body composition.
  
  
  CONCLUSIONS
  These results suggest that reduced fat mass is common in patients with classical homocystinuria, and that alterations in homocysteine and choline pathways affect body mass and lipid metabolism.
authors.affiliation: Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; BRAIN Laboratory (Basic Research and Advanced Investigations in Neurosciences), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil. Electronic address: soraiapoloni@yahoo.com.br.
authors.forename: Soraia
authors.initials: S
authors.lastname: Poloni
authors.affiliation: BRAIN Laboratory (Basic Research and Advanced Investigations in Neurosciences), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Sandra
authors.initials: S
authors.lastname: Leistner-Segal
authors.affiliation: BRAIN Laboratory (Basic Research and Advanced Investigations in Neurosciences), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Isabel Cristina
authors.initials: IC
authors.lastname: Bandeira
authors.affiliation: Reference Center for Inborn Errors of Metabolism, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Vânia
authors.initials: V
authors.lastname: D'Almeida
authors.affiliation: Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Carolina Fischinger Moura
authors.initials: CF
authors.lastname: de Souza
authors.affiliation: Gynecological Endocrinology Unit, Division of Endocrinology, Hospital de Clinicas de Porto Alegre, Department of Physiology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Poli Mara
authors.initials: PM
authors.lastname: Spritzer
authors.affiliation: Food and Nutrition Research Center, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Kamila
authors.initials: K
authors.lastname: Castro
authors.affiliation: Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Tássia
authors.initials: T
authors.lastname: Tonon
authors.affiliation: Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Tatiéle
authors.initials: T
authors.lastname: Nalin
authors.affiliation: Biochemistry-Hormonology Laboratory, Robert Debré Hospital, APHP, Paris, France; Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, University Medical Centre Freiburg, Freiburg, Germany.
authors.forename: Apolline
authors.initials: A
authors.lastname: Imbard
authors.affiliation: Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, University Medical Centre Freiburg, Freiburg, Germany.
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Blom
authors.affiliation: Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; BRAIN Laboratory (Basic Research and Advanced Investigations in Neurosciences), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
authors.forename: Ida V D
authors.initials: IV
authors.lastname: Schwartz
mesh_terms: D050154:Adiposity; D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000097:blood; D015519:Bone Density; D008076:Cholesterol, HDL / Q000097:blood; D002794:Choline / Q000097:blood*; D019856:Ethanolamine / Q000097:blood; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006712:Homocystinuria / Q000097:blood / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008297:Male
chemical_list: D000596:Amino Acids; D008076:Cholesterol, HDL; D006710:Homocysteine; D019856:Ethanolamine; D002794:Choline
keywords: Body composition; Choline; Classical homocystinuria; Homocysteine