No abstract available.
Homocystine ; Homocystinuria*

PURPOSE: The neonatal screening test for homocystinuria primarily measures methionine by using a dried blood specimen. We investigated the incidence and clinical manifestations of homocystinuria, isolated hypermethioninemia, and transient hypermethioninemia among patients with hypermethioninemia on a neonatal screening test. METHODS: We performed a retrospective study of 58 patients transferred to Shoonchunhyang Hospital because of hypermethioninemia on a neonatal screening test between January 1996 and August 2009. We analyzed the level of amino acid from plasma and urine, as well as blood homocysteine. RESULTS: Almost half of the 58 patients were identified as normal. Whereas only 3 (5.1%) patients were identified as having homocystinuria, about 20.7% (12 cases) of the patients had isolated hypermethioninemia. The ages of these two groups at initial detection of hypermethioninemia on plasma amino acid analysis were 50.0+/-22.5 days and 34.9+/-13.5 days, respectively. Both groups were put on diets, and they showed a normal developmental course as a result of early diagnosis and treatment. CONCLUSION: Hypermethioninemia without homocystinuria, referred to as isolated hypermethioninemia, was also detected. Thus, the impact of hypermethioninemia on a neonatal screening test should be carefully evaluated through analysis of amino acid levels from blood and urine, and we need to detect and treat an early stage of isolated hypermethioninemia as well as homocystinuria.
Diet ; Early Diagnosis ; Homocysteine ; Homocystinuria ; Humans ; Incidence ; Infant, Newborn ; Methionine ; Neonatal Screening ; Plasma ; Retrospective Studies

The neonatal screening test for homocystinuria has mostly measured methionine by use of dried blood specimen. Isolated hypermethioninemia, clinically benign metabolic disorder associated with the deficiency of methionine adenosyl transferase in liver, is discovered in neonatal mass screening tests for homocystinuria. We diagnosed two cases of isolated hypermethioninemia using the amino acid analysis and the liver function tests for newborns with increased methionine level in the Guthrie screening test for homocystinuria. For the first time in Korea, we report two cases of patients with isolated hypermethioninemia with a brief review of literatures.
Homocystinuria ; Humans ; Infant, Newborn ; Korea ; Liver ; Liver Function Tests ; Mass Screening* ; Methionine ; Neonatal Screening ; Transferases

PURPOSE: Purpose: To report a case of modified capsular tension ring scleral fixation and in-the-bag toric intraocular lens (IOL) implantation in a pediatric patient with severe crystalline lens subluxation due to homocystinuria. CASE SUMMARY: A 9-year-old male diagnosed with homocystinuria and crystalline lens subluxation presented with progressive decrease of visual acuity. Uncorrected distant visual acuity (UDVA) and corrected distant visual acuity were 0.03 and 0.6 in the right eye and 0.01 and 0.5 in the left eye, respectively. Slit-lamp examination showed severe crystalline lens subluxation toward the inferiomedial side in both eyes. Corneal astigmatism in the right eye and left eye was 2.75 diopters (D) and 3.00 D, respectively based on keratometry. A combination of subluxated crystalline lens aspiration, scleral-fixated modified capsular tension ring insertion and in-the-bag toric IOL implantation were performed in both eyes. After continuous curvilinear capsulorhexis, nucleus and cortex of the crystalline lens were removed by irrigation and aspiration. A modified capsular tension ring with 2 fixation hooks (Model 2-L) was inserted into the capsular bag and fixed at the scleral wall. Next, toric IOL was inserted into the capsular bag. UDVA was 0.8 in the right eye and 0.9 in the left eye and 3 months postoperatively, the IOL rotation was less than 3 degrees from intended axis in both eyes. CONCLUSIONS: In a patient with severe congenital crystalline lens subluxation and moderate to severe corneal astigmatism, scleral fixation of modified capsular tension ring and in-the-bag toric IOL implantation is a possible surgical option.
Astigmatism ; Axis, Cervical Vertebra ; Capsulorhexis ; Child ; Homocystinuria* ; Humans ; Lens Implantation, Intraocular* ; Lens, Crystalline ; Lenses, Intraocular ; Male ; Visual Acuity

Homocystinuria is an inborn error on the pathway of the methionine metabolism. It is mainly caused by a cystathionine B-synthase deficiency in the brain or liver. Homocystinuria is biochemically characterized by: 1) an increase of the homocystine and methionine concentration in the plasma; and 2) a decrease of the cystine with an increased excretion of homocystine in the urine. The clinical manifestations of this autosomal recessive disorder include: ectopoia lentis, skeletal abnormalities, high incidence of thromboembolism and high frequency of mental retardation. We have been experiencing a case of a 10 year old female patient who has suffered from homocystinuria. She has undergone mental retardation, poor vision caused by ocular complications and Marfanoid feautures.
Brain ; Child ; Cystathionine ; Cystine ; Ectopia Lentis* ; Female ; Homocystine ; Homocystinuria* ; Humans ; Incidence ; Intellectual Disability ; Liver ; Metabolism ; Methionine ; Plasma ; Thromboembolism

The trial of external quality assessment for inborn error of metabolism was performed in 2005. Total 11 specimens for the conventional newborn screening tests were distributed to 47 laboratories. The response rates were 92.5% (37/40) and 100% (47/47), in each trial. All the control materials were sent as filter paper forms. Each laboratory replied the test results of the screening items that they were doing as a routine test at the reception of the specimen among PKU screening, TSH, T4 (total/free), galactosemia screen, maple syrup urine disease screen, homocystinuria screen and histidinemia screen. The mean, SD, CV, median and range were analyzed. The pilot proficiency test for newborn screening using tandem mass spectrometry (MS/MS) was also performed. Total 8 blood spots were distributed to 9 laboratories performing newborn screening using MS/MS. Participants' results for amino acids & acylcarnitine and their cutoff values were analyzed.
Amino Acids ; Galactosemias ; Homocystinuria ; Humans ; Infant, Newborn ; Korea* ; Maple Syrup Urine Disease ; Mass Screening ; Metabolism* ; Tandem Mass Spectrometry

OBJECTIVETo analyze mutation types, clinical features, and treatment outcomes of cobalamin C (cblC) type combined methylmalonic aciduria and homocystinuria (MMA-HC) and to investigate the relationship of genotypes with clinical phenotypes and outcomes.

METHODSThe clinical data of 16 Chinese children diagnosed with cblC type MMA-HC by gene analysis were retrospectively analyzed. According to the onset age, the patients were classified into early onset (≤1 year) and late onset (>1 year). According to the clinical phenotype, the patients were classified into mild, moderate, and severe groups. All the patients were treated with vitamin B12 (cyanocobalamin) or hydroxocobalamin, betaine, folate, vitamin B6, and L-carnitine.

RESULTSFifteen patients belonged to the early onset type, including 11 in the severe group and 4 in the moderate group. The remaining one belonged to the late onset type. Seven reported mutations and two novel mutations (c.445_446delTG and c.349G>c) were detected. The c.609G>A and c.658_660delAAG were the most common mutations detected in 13 (81%) out of 16 patients. The genotype caused by compound heterozygous mutations of these two alleles (c.609 G>A/c.658_660delAAG) was the most common in the patients, detected in 4 (25%) out of 16 patients. Patients with this genotype had severe microcephaly and eye diseases and these clinical manifestations were not improved after the treatment. The patient with late-onset cblC type MMA-HC had normal clinical phenotypes after treatment. In the 15 early onset patients, the more severe the clinical phenotype, the worse the treatment outcome.

CONCLUSIONSThe cblC type MMA-HC mainly manifests as early onset in China and c.609G >A and c.658_660delAAG are the most common mutations causing this disease. The clinical phenotypes are associated with the outcomes in children with cblC type MMA-HC.

Child ; Child, Preschool ; Female ; Genotype ; Homocystinuria ; genetics ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation ; Phenotype ; Vitamin B 12 Deficiency ; congenital ; genetics

PURPOSE: Neonatal screening tests are increasingly being used forearly diagnosis of inborn errors of metabolism (IEM) in the hope of avoiding the severe developmental delay, acute illness, and death that may result from these diseases. In this study, a cost-benefit analysis was performed on the neonatal screening of maple syrup urine disease, homocystinuria, galactosemia, and congenital adrenal hyperplasia in Korea. MATERIALS AND METHODS: This study included 1,259,220 Korean newborns born between January 2005 to December 2007, who were screened for maple syrup urine disease, homocystinuria, galactosemia, and congenital adrenal hyperplasia. We calculated and compared the total costs in cases where these four screening tests were implemented, and those where they were not. RESULTS: There were no benefits to screening for maple syrup urine disease or homocystinuria due to their low prevalence for these two tests, the costs exceeded the benefits at benefit:cost ratios of 0.5:1 and 0.6:1, respectively. In contrast, benefits far exceed costs at a ratio of 4.1:1 for galactosemia and 2.9:1 for congenital adrenal hyperplasia. The average benefit:cost ratio for all four tests was 2.0:1. CONCLUSION: Neonatal screening tests for maple syrup urine disease, homocystinuria, galactosemia, and congenital adrenal hyperplasia are financially viable.
Acer ; Adrenal Hyperplasia, Congenital ; Cost-Benefit Analysis ; Galactosemias ; Homocystinuria ; Humans ; Infant, Newborn ; Korea ; Maple Syrup Urine Disease ; Mass Screening ; Metabolism, Inborn Errors ; Neonatal Screening ; Prevalence

Deficiencies of enzymes involved in amino acid metabolism frequently result in accumulation of toxic substances and subsequent organ damage. The brain, liver and kidneys are the most frequently affected organs. Acute symptoms are often associated with catabolic states that lead to the breakdown of endogenous proteins and the release of large amounts of amino acids. The clinical features result from the toxicity of the deficiency, and the extent of protein intake or endogenous amino acid release in protein compensation. Many disorders of this group are recognised by neonatal screening with tandem MS. Most aminoacidopathies are caused by deficiencies of cytosolic enzymes and are recognised by amino acid analysis in plasma (or urine). Treatment usually involves(a) protein restriction, (b) supplementation of amino acids with unimpaired metabolism as well as trace elements, and (c) specific measures for detoxification if indicated. Treatment is not restricted to childhood but usually must be continued throughout life.
Amino Acids ; Brain ; Compensation and Redress ; Cytosol ; Homocystinuria ; Infant, Newborn ; Kidney ; Liver ; Maple Syrup Urine Disease ; Metabolism* ; Neonatal Screening ; Phenylketonurias ; Plasma ; Trace Elements

Two external quality assessment (EQA) trials of conventional newborn screening tests for phenylketonuria, galactosemia, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria, and congenital hypothyroidism, as well as newborn screening tests using tandem mass spectrometry, were performed in 2015. A total of 44 specimens in the form of dried blood spots were distributed to 16 laboratories and the response rate of these laboratories was 100%. The mean, standard deviation, coefficient of variation, median, and cut-offs were evaluated for each analyte in the newborn screening tests. Two EQA trials for the analyses of methylmalonic acid, vanillylmandelic acid, catecholamines, metanephrines, organic acids, and amino acids were also performed. A well-designed EQA program and continuous education would improve the performance of biochemical genetics tests.
Adrenal Hyperplasia, Congenital ; Amino Acids ; Catecholamines ; Congenital Hypothyroidism ; Education ; Galactosemias ; Homocystinuria ; Humans ; Infant, Newborn ; Korea* ; Maple Syrup Urine Disease ; Mass Screening ; Methylmalonic Acid ; Molecular Biology* ; Phenylketonurias ; Tandem Mass Spectrometry ; Vanilmandelic Acid