Environmental influences on familial discordance of phenotype in people with homocystinuria: a case report

Francois Maillot¹^,2 , Jan P Kraus³ and Philip J Lee¹

¹Charles Dent Metabolic Unit, The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK

²CHRU de Tours, Service de Médecine Interne et Nutrition, Tours, France

³DNA Diagnostics Laboratory, University of Colorado at Denver and Health Sciences Center, Aurora, USA

author email corresponding author email

Journal of Medical Case Reports 2008, 2:113doi:10.1186/1752-1947-2-113


Published:	20 April 2008

Abstract

Introduction

Non-heritable factors may have an influence on the clinical expression of monogenic inherited metabolic diseases.

Case presentation

This is a case report of a man whose mother had been diagnosed late in childhood with pyridoxine responsive homocystinuria with lens dislocation and neurodevelopmental delay. These severe complications were not observed in her son who was pyridoxine unresponsive but who had been treated appropriately since early infancy.

Conclusion

The phenotype of people with homocystinuria can be discordant within a family, with variability in metabolic and clinical expression depending upon both the genotype and therapeutic interventions. Offspring of people with homocystinuria should be screened in early infancy and, if positive, treated appropriately whether they have pyridoxine responsive or unresponsive disease.