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Journal of Nutrition and Metabolism
Volume 2017, Article ID 8570469, 7 pages
Research Article

Growth Patterns in the Irish Pyridoxine Nonresponsive Homocystinuria Population and the Influence of Metabolic Control and Protein Intake

1National Centre for Inherited Metabolic Disorders, Temple Street Children’s University Hospital, Dublin, Ireland
2Department of Research, Temple Street Children’s University Hospital, Dublin, Ireland
3Department of Laboratory Medicine, Temple Street Children’s University Hospital, Dublin, Ireland

Correspondence should be addressed to Orla Purcell; ei.huc@llecrup.alro

Received 13 June 2017; Accepted 11 September 2017; Published 15 November 2017

Academic Editor: Pedro Moreira

Copyright © 2017 Orla Purcell et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A low methionine diet is the mainstay of treatment for pyridoxine nonresponsive homocystinuria (HCU). There are various guidelines for recommended protein intakes for HCU and clinical practice varies. Poor growth has been associated with low cystine levels. This retrospective review of 48 Irish pyridoxine nonresponsive HCU patients assessed weight, height, body mass index (BMI), protein intake, and metabolic control up to 18 years at nine set time points. Patients diagnosed through newborn screening (NBS) were compared to late diagnosed (LD) patients. At 18 years the LD group (, mean age at diagnosis 5.09 years) were heavier (estimated effect +4.97 Kg, ) and taller (estimated effect +7.97 cm ) than the NBS group (). There was no difference in growth rate between the groups after 10 years of age. The HCU population were heavier and taller than the general population by one standard deviation with no difference in BMI. There was no association between intermittently low cystine levels and height. Three protein intake guidelines were compared; there was no difference in adult height between those who met the lowest of the guidelines (Genetic Metabolic Dietitians International) and those with a higher protein intake.