Abstract
BackgroundClassical homocystinuria is an autosomal recessive disorder caused by profound cystathionine β‐synthase deficiency. Its biochemical hallmarks are high concentrations of plasma homocyst(e)ine and methionine. Clinical manifestations include lens dislocation, developmental delay, skeletal anomalies, or thromboembolism. Limited literature exists outlining the risk of encephalopathy associated with hypermethioninemia presenting in children with classical homocystinuria.AimTo assess the quality of metabolic control and plasma methionine concentrations in infancy in a cohort of 36 patients with classical homocystinuria in the Republic of Ireland.MethodsReview of biochemical and clinical data including neuroradiological results that are available for the first year of life in our patients diagnosed on newborn screening was performed with appropriate consent and ethical approval.Results and DiscussionMedian total homocyst(e)ine and methionine plasma concentrations were 78 and 55 μmol/L, respectively. Methionine concentrations were significantly higher in neonates as opposed to older children. The highest methionine level identified was 1329 μmol/L in a child who presented clinically with encephalopathy. Elevated homocyst(e)ine and methionine levels are associated with significant morbidities. Therefore, prevention of complications requires prompt recognition and treatment. Chronic and acute complications may be encountered in patients with classical homocystinuria and plasma methionine concentrations pose an additional risk factor.
Highlights
Classical homocystinuria (Online Mendelian Inheritance in Man [OMIM] #236200) is an inherited autosomal recessive disorder, which was first described in the literature independently by Carson and Neill[1] and Gerritsen et al.[2]
A total of 36 patients with classical homocystinuria (17 male, 19 female) diagnosed on newborn bloodspot screening were analyzed. This represents our cohort of patients with classical homocystinuria, diagnosed since the introduction of newborn bloodspot screening in the Republic of Ireland in 1971
Treatment included increased calorie supply and further restriction of natural protein intake with follow-up blood tests. In this case of classical homocystinuria presented here, we identified that hypermethioninemic encephalopathy was characterized by the following features: substantial protein intake for a few days, followed by symptoms resembling an intercurrent illness such as vomiting and progressive neurological deterioration; the patient had a pyridoxine-nonresponsive form
Summary
Classical homocystinuria (Online Mendelian Inheritance in Man [OMIM] #236200) is an inherited autosomal recessive disorder, which was first described in the literature independently by Carson and Neill[1] and Gerritsen et al.[2] It is an inborn error of the metabolism of essential sulfur-containing amino acid methionine caused by a profound deficiency of cystathionine β-synthase (CBS). The gene for this condition is located on chromosome 21 at 21q22.3. Chronic and acute complications may be encountered in patients with classical homocystinuria and plasma methionine concentrations pose an additional risk factor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
