Delayed diagnosis of homocystinuria presenting with coronavirus disease 2019 in a 17-year-old boy

ABSTRACT Homocystinuria is a treatable autosomal recessive inherited disorder. This condition may cause life-threatening complications such as thromboembolic events. Coronavirus disease 2019 (COVID-19) is associated with an increased risk of venous thromboembolic events. Here, we report a case of late diagnosis of homocystinuria presenting with deep venous thrombosis and COVID-19. This study highlights a sustained high index of suspicion for homocystinuria to prevent severe thromboembolic complications.

Homocistinuria, reporte de un caso / Homocystinuria, Case Report / Homocistinuria, relato de um caso

Resumen: En este artículo se presenta el caso de una niña de 13 años con historia de cefalea de 2 años de evolución, la cual ha sido estudiada por subluxación del cristalino y fenotipo marfonoide. Para llevar a cabo la investigación se realizó una tomografía cerebral simple que evidenció trombosis de varios senos cerebrales. Posteriormente se hospitalizó a la paciente en la unidad de cuidados intensivos, mientras se anticoagulaba con enoxaparina. Se solicitó un estudio para trombofilia junto con homocisteina en sangre, ante la sospecha de homocistinuria. Luego de confirmarse el diagnóstico se recetó piridoxina y ácido fólico, con lo cual la paciente evolucionó de manera satisfactoria y recuperó las funciones perdidas. El seguimiento de este caso para la investigación permitió encontrar una disminución mayor del 20 % de la homocisteina, sin que sus niveles estuvieran por debajo de 50 µmol/L, hecho que hace a la paciente respondedora parcial a la piridoxina.

Abstract: This article presents the case of a 13-year-old girl with a 2-year history of headache, which has been studied for lens subluxation and Marfanoid phenotype. To carry out this research, a simple brain tomography was performed that showed thrombosis of several sinuses. Subsequently, the patient was hospitalized in the intensive care unit and anticoagulated with enoxaparin. A study was requested for thrombophilia along with homocysteine in blood, on suspicion of homocystinuria. After confirming the diagnosis, pyridoxin and folic acid were prescribed, with which the patient evolved satisfactorily and recovered lost functions. Follow-up on this case for the research allowed us to find a decrease in homocysteine greater than 20 %, without its levels being below 50 µmol/L, which makes the patient partially responsive to pyridoxine.

Resumo: Neste artigo, é apresentado o caso de uma menina de 13 anos, com história de cefaleia de dois anos de evolução, a qual tem sido estudada por subluxação do cristalino e fenótipo marfanoide. Para realizar a pesquisa, foi tomada uma tomografia cerebral simples que evidenciou trombose de vários seios cerebrais. Em seguida, a paciente foi internada na unidade de tratamento intensivo onde recebeu tratamento anticoagulante com enoxaparina. Foi solicitado um estudo para trombofilia junto com homocisteina em sangue, diante da suspeita de homocistinúria. Após o diagnóstico ter sido confirmado, foram receitados piridoxina e ácido fólico, com os quais o estado da paciente evoluiu de maneira satisfatória e ela recuperou as funções perdidas. O seguimento do caso para a pesquisa permitiu verificar uma diminuição maior de 20% da homocisteina, sem que seus niveis estivessem abaixo de 50 µmol/L, fato que torna a paciente apta parcialmente à piridoxina.

Three Main Causes of Homocystinuria: CBS, cblC and MTHFR Deficiency. What do they Have in Common?

Abstract Genetic homocystinurias are a group of inborn errors of metabolism that result in the massive excretion of homocysteine (Hcy) in the urine due to Hcy accumulation in the body, usually causing neurological and cardiovascular complications. The three most frequent causes are classical homocystinuria [deficiency of cystathionine beta-synthase (CBS)], methylmalonic aciduria with homocystinuria, cblC type (cblC deficiency) and severe methylenetetrahydrofolate reductase (MTHFR) deficiency. In this review, we highlight the similarities and differences among these disorders. Briefly, their joint manifestation is the accumulation of tHcy, however, the other sulfur amino acids show various and even invers profiles. Vascular disease, developmental delay and seizures are found in all homocystinurias, nevertheless, the complications of CNS differ in a wide variety of presentations and severities and are apparently less pronounced in CBS deficiency. Moreover, patients with remethylation defects typically do not present ectopia lentis and bone disturbances, tall stature and osteoporosis. Whereas hematological alterations, such as megaloblastic anemia, thrombocytopenia neutropenia and life-threatening microangiopathy, are specific findings of cblC deficiency.

Classic homocystinuria and keratoconus: a case report / Homocistinúria clássica e ceratocone: um relato de caso

ABSTRACT Homocystinuria is one of a group of genetic disorders called inborn errors of metabolism. It is characterized by a deficiency of the enzyme that converts homocysteine to cystathionine. Keratoconus is an ophthalmologic condition characterized by thinning of the corneal stroma, which causes the cornea to assume a conical shape. There is little information in the scientific literature about the association between keratoconus and homocystinuria. We believe that a collagen cross-linking defect may be the key to understand the connection between these two conditions. This case report describes a 38-year-old male patient with a diagnosis of classical homocystinuria since age 13. At the age of 16, he received a diagnosis of asymmetrical keratoconus when referred for lensectomy with vitrectomy of his left eye. To the best of our knowledge, this is the first report of a patient with simultaneous homocystinuria and keratoconus.

RESUMO Homocistinúria é parte de um grupo de doenças genéticas chamado erros inatos do metabolismo. É caracterizada por uma deficiência da enzima que converte a homocisteína em cistationina. O ceratocone é uma patologia oftalmológica caracterizada pelo afinamento do estroma corneano, o que faz com que a córnea assuma um formato cônico. Há pouca informação na literatura científica sobre a associação entre ceratocone e homocistinúria. Acreditamos que um defeito no cross-linking do colágeno possa ser a chave para entender a conexão entre estas duas condições. Este relato de caso descreve um paciente masculino de 38 anos com diagnóstico de homocistinúria clássica desde os 13 anos. Aos 16 anos, recebeu o diagnóstico de ceratocone assimétrico quando foi encaminhado para lensectomia com vitrectomia do olho esquerdo. Até onde sabemos, este é o primeiro relato de um paciente com homocistinúria e ceratocone simultâneos.

Diagnosis and Management of Classica Homocystinuria in Brazil: A Summary of 72 Late-Diagnosed Patients

Abstract This study described a broad clinical characterization of classical homocystinuria (HCU) in Brazil. This was a cross-sectional, observational study including clinical and biochemical data from 72 patients (60 families) from Brazil (South, n = 13; Southeast, n = 37; Northeast, n = 8; North, n = 1; and Midwest, n = 1). Parental consanguinity was reported in 42% of families. Ocular manifestations were the earliest detected symptom (53% of cases), the main reason for diagnostic suspicion (63% of cases), and the most prevalent manifestation at diagnosis (67% of cases). Pyridoxine responsiveness was observed in 14% of patients. Only 22% of nonresponsive patients on treatment had total homocysteine levels <100 mmol/L. Most commonly used treatment strategies were pyridoxine (93% of patients), folic acid (90%), betaine (74%), vitamin B12 (27%), and low-methionine diet + metabolic formula (17%). Most patients diagnosed with HCU in Brazil are late diagnosed, express a severe phenotype, and poor metabolic control. Milder forms of HCU are likely underrepresented due to underdiagnosis.

Iris-claw intraocular lens implantation in children with ectopia lentis / Implante de lente intraocular de fixação iriana em crianças com ectopia lentis

ABSTRACT Purpose: Artisan iris-claw lens implantation (AICLI) is a surgical technique for treating ectopia lentis. We aimed to compare visual outcomes and possible long-term complications of AICLI surgery in pediatric patients with ectopia lentis with or without a diagnosable hereditary disease. Methods: Seventeen children with non-traumatic ectopia lentis were retros pectively classified into two groups: group 1 included children with a diagnosable hereditary disease (11 patients, 65%), and group 2 included children without any definable hereditary disease (six patients, 35%). Patients were evaluated for post-surgical refraction, best-corrected visual acuity, and clinical follow-up complications. Results: The average follow-up time was 38 months, and the average age of the patients was 103 ± 53 months (30-196 months). Best-corrected visual acuity values were significantly increased in both groups after surgery (p<0.05). Target refraction values were achieved at a rate of 47% in group 1 and 22% in group 2. Post-surgery complications, such as lens dislocation (36%, 11 eyes of 10 patients) and hypotonia (10%, three eyes of three patients) were observed in both groups, and retinal detachments (10%, three eyes of three patients) were observed in three patients from group 1. Conclusions: Compared with previous similar studies, this study utilized the largest pediatric patient group and had the longest post-surgery follow-up time. Moreover, it is advisable that pediatric patients with non-traumatic ectopia lentis be carefully screened for any underlying hereditary disease, especially diseases related to connective tissue metabolism.

RESUMO Objetivo: A implantação de lentes intraoculares de fixação iriana em garra (AICLI) é uma técnica cirúrgica para o tratamento de ectopia lentis. Nosso objetivo foi comparar resultados visuais e possíveis complicações em longo prazo da cirurgia de AICLI em pacientes pediátricos com ectopia lentis com ou sem doença hereditária diagnosticável. Métodos: Dezessete crianças com ectopia lentis não-traumática foram classificadas retrospectivamente em dois grupos: o grupo 1 com pacientes apresentando doença hereditária diagnosticável (11 pacientes, 65%) e o grupo 2 com pacientes sem qualquer doença hereditária definível (6 pacientes, 35%). Os pacientes foram avaliados quanto à sua refração pós-operatória, acuidade visual melhor corrigida e complicações. Resultados: O tempo médio de seguimento foi 38 meses. A média de idade dos pacientes foi de 103 ± 53 meses (30-196 meses). Os valores de acuidade visual me lhor corrigida aumentaram significativamente em ambos os grupos (p<0,05). Os valores de refração alvo foram alcançados a uma taxa de 47% no grupo 1 e 22% no grupo 2. Complicações pós-operatórias como luxação da lente (36%, 11 olhos de 10 pacientes) e hipotonia (10%, 3 olhos de 3 pacientes) foram observados nos dois grupos e foram observados descolamentos de retina (10%, 3 olhos de 3 pacientes) em 3 pacientes do grupo 1. Conclusões: Em comparação com relatos anteriores na literatura, este estudo utilizou um grupo maior de pacientes pediátricos e tempo de seguimento pós-operatório mais longo. É aconselhável que pacientes pediátricos com ectopia lentis não-traumática sejam cuidadosamente selecionados em relação a doença subjacente hereditária, especialmente as doenças relacionadas com o metabolismo do tecido conjuntivo.

MMACHC gene mutation analysis in the prenatal diagnosis of methylmalonic aciduria with homocystinuria / 中华检验医学杂志

Objective To analyse MMACHC mutations for 45 pedigrees with combined methylmalonic aciduria and homocyctinuria by Sanger sequencing, and to discuss the utility of prenatal genetic diagnosis for these pedigrees.Method Peripheral blood was collected from 45 probands and their parents from 2012-2015 in Genetic Counselling Clinic of the First Affiliated Hospital of Zhengzhou University, and the DNA were extracted from the blood.Then the coding sequence of MMACHC gene was amplified by PCR, and the PCR products were further sequenced to detect mutations for each pedigree.For 12 families, chorionic villus sampling was performed on the pregnant women to make prenatal genetic diagnosis.Result There were 14 distinct mutations detected in the 45 pedigrees, and the most frequent mutations are c.609G>A(W203X),c.658-660delAAG(K220del)and c.80A>G (Q27A).Two of those mutations have not been reported before:one is a splicing site mutation c.81+1G>A;while the other is a missense mutation c.665A>G,p.Y222C.Most mutations were found in exon 4.Among the 12 pedigrees who received prenatal diagnosis, 2 fetuses were normal, 7 fetuses were carriers of heterozygous mutation, and the other 3 fetuses were patients with compound heterozygous mutation or homozygous mutation.The couples whose fetuses were normal or carriers continued the gestation, while the couples whose fetuses were patients decided to terminate the pregnancy.After delivery, the outcome of the fetuses was the same as the prenatal diagnose results.Conclusion Two novel mutations of MMACHC were identified and prenatal genetic diagnosis helps to avoid the delivery of combined methylmalonic aciduria and homocyctinuria patients.

Modified Capsular Tension Ring Scleral Fixation and Toric Intraocular Lens Implantation in a Patient with Homocystinuria

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.

Implantação de lente intraocular com uma alça amputada: proposta para o tratamento cirúrgico da subluxação do cristalino / Intraocular lens implantation with one loop haptic amputed: a new propose to the subluxation lens surgical treatment

OBJETIVO: Avaliar os resultados pós-operatórios da subluxação congênita do cristalino, corrigida por uma nova abordagem cirúrgica. MÉTODOS: Foram estudados 21 olhos de 13 pacientes, portadores de subluxação não traumática do cristalino submetidos à cirurgia na Fundação Altino Ventura, no período de abril de 1999 a abril de 2004. A idade média foi de 8,7 ± 5,4 anos, e o tempo médio de seguimento foi 21,5 ± 19,3 meses. Os pacientes foram submetidos à facoaspiração, implante do anel endocapsular e lente intraocular (LIO). Uma das alças da LIO foi amputada e apoiada sobre o anel, no interior do saco capsular, centralizando a LIO. RESULTADOS: Houve melhora da acuidade visual (AV) em todos os casos, e redução significante do equivalente esférico e componente esférico comparando-se a refração pré e pós-operatória (p<0,01). Não houve diferença entre o componente cilíndrico pré e pós-operatório (p=0,71). Opacificação da cápsula posterior do cristalino foi a complicação encontrada em 71,4 por cento dos casos. Foi realizada capsulotomia posterior precoce nestes pacientes sem intercorrências. CONCLUSÃO: Implante de LIO com uma alça amputada e apoiada sobre o anel endocapsular é uma opção no tratamento cirúrgico da subluxação congênita do cristalino, podendo-se observar centralização da LIO e melhora da AV no pós-operatório.

PURPOSE: To evaluate the postoperative results of congenital lens subluxation corrected by a new technique. METHODS: Retrospective chart review of 21 eyes of 13 patients with no traumatic lens subluxation who underwent surgery in Altino Ventura Foundation from April, 1999 to April, 2004. The mean age was 8.7 ± 5.4 years old, and the mean follow-up period was 21.5 ± 19.3 months. Patients underwent phacoaspiration, endocapsular ring and intraocular lens (IOL) implantation. The implanted IOL had one loop haptic excised and was supported above the ring, inside the capsular bag promoting intraocular lens centralization. RESULTS: Visual acuity improvement was observed in all cases. There was a significant reduction of the spherical equivalent and spherical component comparing the pre and postoperative refraction (p<0.01). There was no statistically significant difference between the pre and postoperative cylinder component (p=0.71). Posterior capsule opacification was a postoperative complication found in 71.4 percent of the cases. Early posterior capsulotomy was performed with no complications in these cases. CONCLUSION: Intraocular lens implantation with one loop haptic amputed and supported above the endocapsular ring is an option for the congenital lens subluxation surgical treatment, promoting lens centralization and postoperative visual acuity improvement.

Spectrum of patients with hypermethioninemia based on neonatal screening tests over 14 years / 소아과

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.

Homocistinuria: informe de 2 pacientes / Homocystinuria: Report of 2 patients

Introducción. Homocistinuria es la segunda causa de aminoacidopatías, después de fenilcetonuria. Se hereda en forma autosómica recesiva. El defecto está en el cromosoma 21 q 22.3. Incidencia: 1:300 000 a 1:60 000. Es un trastorno del metabolismo de la metionina con aumento de homocisteína, y alteraciones en ojos y sistemas nervioso central, cardiovascular y esquelético. Casos clínicos. Mujeres de 9 y 11 años, con retardo psicomotor, pérdida de la agudeza visual y actividad motora, subluxación de cristalino, nistagmo, mala oclusión dentaria, prognatismo, escápulas aladas, aracno y clindactilia, genuvalgo, pie cavo, ataxia y signo de Romberg positivo. Tamiz metabólico: caso 1: metionina 1 194 (normal 7-47 ng/mL), B12 1 167 (normal 220-960 pg/mL), folatos 20-7.2 (normal 3-17 ng/ mL). Caso 2: metionina 180-1 740, vitamina B12: 1 749 y 1 744, folatos 3. Tratamiento: piridoxina, folatos, vitamina C, B12 y aspirina. Evolución estable. Conclusión. El diagnóstico oportuno de homocistinuria previene complicaciones.

Introduction. Homocystinuria is a metabolic disorder of methionine which results elevated homocysteine, visual, central nervous system, cardiovascular system and skeletal disturbances, and the second most frequent amino acid disorder after phenylcetonuria. It is a recessive autosomic hereditary condition. The defect is located in chromosome 21q22-3. Incidence: 1:300 000 to 1:60 000. Case reports. Two girls ages 9 and 11 years presented with mental retardation, loss of visual acuity and of motor activity; lens sub luxation, nistagmus, ataxia and positive Romberg's sign. Metabolic screening: Case 1: methionine, 1 194 ng/mL (normal, 7-47 ng/mL); B12, 1 167 pg/mL (normal, 120-960 pg/mL); folates, 20-7.2 ng/mL (normal, 3-17 ng/mL). Case 2: methionine, 180-1 740; vitamin B12, 1 749; folates 3 (normal 3-17 ng/mL). Treatement: pyridoxine, folates, vitamin C, B12 and aspirin. The clinical course of these patients has been stable. Conclusion. Early diagnosis of homocystinuria prevents complications.

Recombinant adeno-associated virus mediated gene transfer in a mouse model for homocystinuria

Homocystinuria is a metabolic disorder caused by a deficiency of cystathionine b-synthase (CBS). The major clinical symptoms of this disease are mental retardation, lens dislocation, vascular disease with life-threatening thromboembolisms, and skeletal deformities. The major treatments for CBS deficiency include pharmacologic doses of pyridoxine or dietary restriction of methionine. There is currently no effective long-term treatment to lower the elevated plasma levels of homocysteine. However, gene therapy could be an effective novel approach for the treatment of homocystinuria. A recombinant adeno- associated virus vector carrying human CBS cDNA (rAAV-hCBS) was constructed and administered to CBS-/- mice by intramuscular (IM) and intraperitoneal (IP) injections. Serum homocysteine concentrations significantly decreased in treated mice compared with age-matched controls two weeks after treatment. The treated CBS-/- mice had life spans 3-7 days longer compared with untreated CBS-/- mice. In CBS-/- mice treated with rAAV-hCBS via IP injection, the vector was detected in all organs examined including liver, spleen, and kidney, and CBS gene expression was observed by immunohistochemical staining in the liver. These results indicate the efficacy of gene delivery and demonstrate the possibility of gene therapy mediated by AAV gene transfer in this mouse model of homocystinuria.

Amino acid metabolism disorders / 한양의대학술지

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.

A Case of Homocystinuria Complicated with Systemic Deep Vein Thrombosis and Venous Infarction of Thalamus / 대한소아신경학회지

Homocystinuria is an autosomal recessive inherited disorder of methionine metabolism. The most common cause of homocystinuria is cystathione-beta-synthase deficiency, which has the characteristic clinical features such as ectopia lentis, Marfanoid skeletal changes, mental retardation, and vascular thromboembolic events such as deep vein thrombosis, cerebral infarction, pulmonary embolism, and myocardial infarction. The thromboembolic vascular events occur in 20-50% of untreated patients with homocystinuria at the age of 15, and could be associated with vasculopathy related mortality in 20% of untreated patients before the age of 30. Therefore, homocystinuria is one of the important cause of stroke in children and young adults. Only 2 cases of homocystinuria were reported in Korea; one without vasculopathy and the other with cerebral infarction. Homocystinuria complicated with systemic deep vein thrombosis is first reported in Korea. We report a 13 year old female with homocystinuria complicated with severe systemic deep vein thrombosis and venous infarction of both thalami due to thrombosis of vein of Galen and internal cerebral vein.

A Case of Homocystinuria with Ectopia Lentis

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.