Homocystinuria is an inherited metabolic disorder characterised by an increased blood and urine concentration of homocysteine and its metabolites. The clinical features of homocystinuria include myopia, ectopia lentis, skeletal anomalies and intellectual disability. The classic form of homocystinuria is caused by homozygous or compound heterozygous mutation in the CBS gene which encode an enzyme called cystathionine beta-synthase - an important component in the chemical pathway that coverts homocysteine to cystathionine.
Five cases of homocystinuria were reported by Yadav and Reavey (1988), while studying the aminoacid profiles of 800 subjects during the course of three years in Al-Sabah Hospital, Kuwait.
In a study conducted to investigate the incidence of aminoacidopathies in intellectually disabled patients (187 institutionalized patients), Yadav et al. (1992) reported one case (0.23%) of homocystinuria.
In a retrospective analysis of IEMs diagnosed over a 12-year period (1998-2010) in a hospital in Lebanon, Karam et al. (2013) found 8 patients diagnosed with homocystinuria. The median age of diagnosis was 3-years.
Joshi et al. (2002) carried out a retrospective analysis of all patients diagnosed with inborn errors of metabolism in Sultan Qaboos University Hospital, Oman between June 1998 and December 2000. Among the 82 patients studied, one case of homocystinuria was reported.
Al-Riyami et al. (2012) reported three cases of homocystinuria in a study group of 1100 high-risk neonates referred to Sultan Qaboos University Hospital in Oman over a 10-year period (1998-2002).
In a comparative study conducted by Elsaid et al. (2007), heterozygous carriers of CBS gene mutations were found to have increased levels of homocysteine, reduced levels of folic acid and B12 as compared to the control subjects. B6 levels between both groups did not have any significant differences.
Lindner et al. (2007) investigated 25,214 neonates born in Qatar for inborn errors of metabolism and endocrine disorders. Two neonates were diagnosed with classic homocystinuria.
The Centre for Arab Genomic Studies Work Group (2006) conducted a retrospective study for metabolic disorders described at Al Wasl Hospital in Dubai between 1995 and 2004. Among 64 patients diagnosed, only one case of homocystinuria was reported - in a 10-year-old male from Qatar.
Moammar et al. (2010) reported incidence of homocystinuria as 2 in 100,000 live births based on a study conducted at Saudi Aramco medical facilities in the Eastern province of Saudi Arabia. All patients diagnosed with inborn errors of metabolism between 1983 to 2008 were included in the study. Out of 165530 infants born, four cases of classic homocystinuria were reported.
Harrison et al. (1998) reviewed the management of ophthalmic complications of homocystinuria in 45 patients. All patients were noted to have a history of lens subluxation or dislocation.
[See: Qatar > CAGS Work Group, 2006].