Phenotypic and molecular features of Thai patients with primary carnitine deficiency.

BACKGROUND: Primary carnitine deficiency (PCD) is screened by expanded newborn screening (NBS) using tandem mass spectrometry (MS/MS) that can detect both affected neonates and mothers. This study aimed to delineate the clinical, biochemical, and molecular findings of Thai PCD patients. METHODS: Expanded NBS using MS/MS was implemented in Bangkok and 146,757 neonates were screened between 2014 and 2018. PCD was screened by low free carnitine (C0) levels in dried blood spots. Plasma C0 levels and C0 clearance values were measured in neonates and their mothers with positive screening results. Clinically diagnosed cases were described. The coding regions and intron-exon boundaries of the SLC22A5 gene were sequenced in all cases with low plasma C0 levels. RESULTS: There were 14 cases with confirmed PCD: two clinically diagnosed cases, and 12 cases identified through NBS including five newborns, six mothers, and one older sibling. Thus, the incidence of PCD in neonates was 1:29,351. All affected neonates and mothers were asymptomatic except one mother with dilated cardiomyopathy. SLC22A5 gene sequencing identified biallelic causative variants in all cases, comprising 10 different variants of which four were novel. c.51C > G (p.Phe17Leu) and c.760C > T (p.Arg254Ter) were the most prevalent variants in this study. Cases with significant clinical features tended to have higher C0 clearance values. CONCLUSIONS: Primary carnitine deficiency is a common inherited metabolic disorder (IMD) in Thailand. Our findings broaden the spectrum of SLC22A5 variants. The future national NBS program will shed more light on PCD and other IMDs in Thailand.

Molecular characterization of Thai patients with phenylalanine hydroxylase deficiency and in vitro functional study of two novel PAH variants.

Phenylketonuria (PKU) is an autosomal recessive amino acid metabolism disorder caused by variants in the gene encoding phenylalanine hydroxylase (PAH; EC1.14.16.1). This study aimed to assess the specific heterogeneity of PAH variants found in Thai population as well as evaluate enzyme activity and expression of novel variants. PAH gene from 13 patients was analyzed by PCR amplification and direct Sanger-sequencing of 13 exons of the coding region. The novel variants were transiently transfected in COS-7 cells for functional verification. Eleven different PAH variants were identified: all pathogenic variants were missense variants, of which the most frequent variant was p.R169L, accounting for 24% (6/25) of all identified alleles. Two novel variants p.R169L and p.Y317N and previously reported variants with mutated residues at the same positions (p.R169H and p.Y317H) were expressed in COS-7 cells. These showed mildly impaired residual activity levels (42.3-63.1% of wild type), while the protein levels were well expressed (82.8-110%), except for p.R169L, which showed decreased protein expression of 55.7% compared to the wild type enzyme. All subjects with p.R169L identified in at least one of pathogenic alleles (one case is homozygous) had a metabolic phenotype of mild hyperphenylalaninemia (HPA). Our data has expanded the information on the genetic heterogeneity of Thai patients with PAH deficiency. This finding emphasizes the importance of genotyping in patients with HPA, and in vitro studies can provide additional information for prediction of phenotype.

Analysis of Novel Mutations and Methylmalonyl-CoA Mutase Levels in Thai Patients with Isolated Methylmalonic Acidemia.

Isolated methylmalonic acidemia (MMA) is an autosomal recessive, inherited disorder that results from either a mut defect of the methylmalonyl-CoA mutase apoenzyme (MCM, the product of the MUT gene) or a cbl defect in the synthesis of its cofactor, adenosylcobalamin (AdoCbl). In this study, biochemical and mutational analyses of three patients clinically diagnosed with MMA were performed. No MCM activity was detected in leukocyte extracts of two patients, while high MCM activity was found in the other, suggesting mut (0) and cbl defects, respectively. A novel (c.IVS6 -3 to -8delCTTTTT, p.K444_L445insFC*) and two known mutations in the MUT gene and one novel (c.227_36delGACCCAAAGA, p.R76Mfs*14) mutation in the MMAB gene were identified. In addition, MCM immunoblot analysis of leukocyte extract samples of these three patients and eight patients previously reported by our group, as well as their parents, showed a good correlation between the MCM protein and activity levels. Patients with mut (0) defective subtypes lacked MCM activity and had no MCM band, while patients carrying the cbl defects had high MCM activity levels and an intense MCM band at about 83 kDa, in comparison to those in their parents. These data expand the mutation spectrum of MMA deficiency. In addition, the examination of MCM protein level may be used as an alternative technique to determine the mut (0) and cbl defective subgroups.

Clinical characteristics and mutation analysis of propionic acidemia in Thailand.

BACKGROUND: Propionic acidemia (PA) is caused by a deficiency of propionyl CoA carboxylase. A characteristic urine organic acid profile includes 3-hydroxypropionate, methylcitrate, tiglylglycine, and propionylglycine. The diagnosis of PA is confirmed by detection of mutations in the PCCA or PCCB genes. We herein report the clinical and molecular findings of four Thai patients with PA. METHODS: Clinical findings of four Thai patients with PA were retrospectively reviewed. Urine organic acids were analyzed by gas chromatography-mass spectrometry. PCR-sequencing analyses of encoding exons and intron/exon boundaries of the PCCA and PCCB genes were performed. RESULTS: All patients had neonatal onset of PA. One patient died of cardiomyopathy, and another one of pneumonia and metabolic decompensation. The remainder experienced significant neurocognitive impairment. Mutation analysis of the PCCA gene identified homozygous c.1284+1G>A in patient 1, c.230G>A (p.R77Q) and c.1855C>T (p.R619X) in patient 2, homozygous c.2125T>C (p.S709P) in patient 3, and only one mutant allele, c.231+1G>T in patient 4. No PCCB mutation was identified. Four mutations including c.230G>A, c.231+1G>T, c.1855C>T, and c.2125T>C have not been reported previously. CONCLUSIONS: The clinical and molecular study of these Thai patients provided additional knowledge of the genotype and phenotype characteristics of PA. The results of the study suggested that PCCA mutations in Asian populations were distinct from those of other populations.

Clinical and molecular findings in Thai patients with isolated methylmalonic acidemia.

Isolated methylmalonic acidemia (MMA) is a genetically heterogeneous organic acid disorder caused by either deficiency of the enzyme methylmalonyl-CoA mutase (MCM), or a defect in the biosynthesis of its cofactor, adenosyl-cobalamin (AdoCbl). Herein, we report and review the genotypes and phenotypes of 14 Thai patients with isolated MMA. Between 1997 and 2011, we identified 6 mut patients, 2 cblA patients, and 6 cblB patients. The mut and cblB patients had relatively severe phenotypes compared to relatively mild phenotypes of the cblA patients. The MUT and MMAB genotypes were also correlated to the severity of the phenotypes. Three mutations in the MUT gene: c.788G>T (p.G263V), c.809_812dupGGGC (p.D272Gfs*2), and c.1426C>T (p.Q476*); one mutation in the MMAA gene: c.292A>G (p.R98G); and three mutations in the MMAB gene: c.682delG (p.A228Pfs*2), c.435delC (p.F145Lfs*69), and c.585-1G>A, have not been previously reported. RT-PCR analysis of a common intron 6 polymorphism (c.520-159C>T) of the MMAB gene revealed that it correlates to deep intronic exonization leading to premature termination of the open reading frame. This could decrease the ATP:cobalamin adenosyltransferase (ATR) activity resulting in abnormal phenotypes if found in a compound heterozygous state with a null mutation. We confirm the genotype-phenotype correlation of isolated MMA in the study population, and identified a new molecular basis of the cblB disorder.

Amino acid disorders detected by quantitative amino acid HPLC analysis in Thailand: an eight-year experience.

BACKGROUND: Amino acid disorders are a major group of inborn errors of metabolism (IEM) with variable clinical presentations. This study was aimed to provide the data of amino acid disorders detected in high-risk Thai patients referred to our metabolic lab from all over the country. METHODS: From 2001 to 2009, we analyzed amino acids by HPLC in 1214 plasma and cerebrospinal fluid specimens. These specimens were obtained from patients with clinical suspicion of IEM or with positive newborn screening. The clinical data of the patients with confirmed diagnoses of amino acid disorders were also analyzed. RESULTS: Fifty-eight patients were diagnosed with amino acid disorders, including 20 cases (34.5%) with maple syrup urine disease, 13 (22.4%) with phenylketonuria and hyperphenylalaninemia, 13 (22.4%) with nonketotic hyperglycinemia, 9 (15.5%) with urea cycle defects, 2 (3.4%) with classical homocystinuria, and 1 (1.7%) with ornithine aminotransferase deficiency. There was considerable delay in diagnoses which led to poor outcomes in most patients. CONCLUSION: The prevalence of amino acid disorders in Thailand is distinct from other countries. This will guide the selection of the prevalent IEM for the future expansion of newborn screening program in this country.

Phenotypic and mutation spectrums of Thai patients with isovaleric acidemia.

BACKGROUND: Isovaleric acidemia (IVA) is an autosomal recessive disorder caused by deficiency of isovaleryl-CoA dehydrogenase (IVD). Clinical features include vomiting, lethargy, metabolic acidosis, and "sweaty feet" odor. The pathognomonic metabolite, isovalerylglycine, is detected on urine organic acid analysis. Clinical diagnosis of IVA can be confirmed on mutation analysis of the IVD gene. METHODS: The cases of five unrelated Thai patients with IVA, identified on urine organic acid analysis, are described. Mutation analysis of the IVD gene was performed using polymerase chain reaction sequencing of the entire coding regions. RESULTS: Four out of the five IVA patients had an acute neonatal form. The hematologic abnormalities were common and thus could be presenting symptoms in the absence of metabolic acidosis. As for the neurological outcome, only one patient had normal intelligence. Mutation analysis of the IVD gene identified the mutations c.457-3_2CA>GG, c.1199A>G (p.Y371C), c.281C>G (p.A65G), c.358G>A (p.G91R), and c.827T>C (p.L247P). The poor outcome in most patients might be explained by the delayed diagnosis and initial unavailability of the metabolic formulas and medications in Thailand. The c.457-3_2CA>GG mutation was identified in all of the present patients. This suggests that it is the most common mutation in the Thai population. Therefore, it could be a founder mutation in Thai subjects. One of the present Thai IVA patients also had the p.Y371C mutation, which is common in Han Chinese subjects. In addition, two novel mutations, p.A65G and p.L247P, were identified. CONCLUSION: The present study provides additional knowledge on the genotype-phenotype of IVA, suggesting that IVD mutations in Asian populations are distinct from these in Western populations.

Glutaric aciduria type 2, late onset type in Thai siblings with myopathy.

Reported here is a novel presentation of late onset glutaric aciduria type 2 in two Thai siblings. A 9-year-old boy presented with gradual onset of proximal muscle weakness for 6 weeks. The initial diagnosis was postviral myositis, and then polymyositis. Electromyography and nerve conduction velocity testing indicated a myopathic pattern. Muscle biopsy revealed excessive accumulation of fat. Acylcarnitine profiling led to the diagnosis of glutaric aciduria type 2. Immunoblot analysis of electron-transferring-flavoprotein and its dehydrogenase electron-transferring-flavoprotein dehydrogenase led to mutation analysis of the ETFDH gene, which revealed two different pathogenic mutations in both alleles and confirmed the diagnosis of glutaric aciduria type 2 caused by electron-transferring-flavoprotein dehydrogenase deficiency. The boy recovered completely after treatment. Later, his younger sibling became symptomatic; the same diagnosis was confirmed, and treatment was similarly effective. Acylcarnitine profiling was a crucial investigation in making this diagnosis in the presence of normal urine organic acid findings. Late onset glutaric aciduria type 2, a rare cause of muscle weakness in children, should be included in the differential diagnosis of myopathy.

Factors influencing development of Down syndrome children in the first three years of life: Siriraj experience.

OBJECTIVE: To analyze factors influencing development of Down syndrome children in the first three years of life. MATERIAL AND METHOD: A cross-sectional study was conducted in 100 Down syndrome (DS) children attending at the Genetics clinic, Department of Pediatrics, Siriraj Hospital between January 2002 and December 2005. All individuals were three to six years of age. The data was collected from January to December 2006, including general information and factors on the child and their families. The child developmental quotient (DQ) was evaluated by Capute Scales Cognitive Adaptive Test/Clinical Linguistic & Auditory Milestones Scale (CAT/CLAMS) at three years of age. Data were analyzed by descriptive statistic and multiple linear regression with the significant level at p-value < 0. 05. RESULTS: The mean development quotient (DQ) was 63.78 +/- 11.25 (range 32-91) with the majority being mild developmental delay. The child and family factors contributing to developmental quotient (DQ) outcome were birthplace, congenital heart disease, age at the first genetic counseling, regular follow-up in the Genetics clinic, age at the first early stimulation program/speech training program, parental education/occupation, and family income. Only family income and age at the first speech-training program were found to be independently associated with developmental quotient (DQ) at the age of three years (p-value < 0.05). CONCLUSION: Down syndrome is the most common genetic cause of mental retardation. Various factors contribute to developmental quotient (DQ) outcome but the most important factors are family income and age at the first speech-training program. Therefore, Down syndrome children with the above factors should be followed-up and monitored closely for the optimal long-term outcome.

Organic acid disorders detected by urine organic acid analysis: twelve cases in Thailand over three-year experience.

BACKGROUND: Disorders of organic acid (OA) metabolism are generally detected by qualitative analysis of urine organic acids by gas chromatography/mass spectrometry (GC/MS) which was well established in developed countries since 1980s. Confirmation of the diagnosis of organic acid disorders by OA analysis, enzyme analysis and molecular study is a difficult task in developing countries. METHODS: During 2001-2004, we had analysed 442 urine samples in 365 patients and identified 12 cases of organic acid disorders. RESULTS: We identified the following disorders: alkaptonuria (ALK)=1, isovaleric acidemia (IVA)=3, propionic acidemia (PA)=2, methylmalonic acidemia (MMA)=3, glutaric aciduria, type I (GA-I)=1, multiple carboxylase deficiency (MCD)=1, and glutaric acidemia, type II (GA-II)=1. CONCLUSIONS: OA disorders had never been diagnosed in Thailand before, until GC/MS technology was introduced to Thailand in 2001. Urine OA analysis also provided a diagnostic clue to other inborn errors of metabolism including amino acid disorders, urea cycle disorders, disorders of carbohydrate metabolism, and mitochondrial fatty acid oxidation disorders. Since then, we were able to diagnose numerous disorders, which led to prompt treatment and better outcome in our patients.

Novel mutations found in two genes of thai patients with isolated methylmalonic acidemia.

Molecular genetic analysis of three patients diagnosed with isolated methylmalonic acidemia (MMA) revealed that one was mut (0) MMA, with a mutation in the MUT gene encoding the L: -methylmalonyl-CoA mutase (MCM), and two were cblB MMA, with mutations in the MMAB gene required for synthesizing the deoxyadenosylcobalamin cofactor of MCM. The mut (0) patient was homozygous for a novel nonsense mutation in MUT, p.R31X (c.167C --> T), and heterozygous for three previously described polymorphisms, p.K212K (c.712A --> G), p.H532R (c.1671A --> G), and p.V671I (c.2087G --> A). The new MMAB mutation, p.E152X (c.454G --> T), was found to be homozygous in one cblB patient and heterozygous in the other patient, who also had four intron polymorphisms in this gene.

Retrospective study of patients with suspected inborn errors of metabolism at Siriraj Hospital, Bangkok, Thailand (1997-2001).

INTRODUCTION: This retrospective clinical study was carried out on patients with suspected inborn errors of metabolism (IEM) at Siriraj Hospital during 1997-2001. The authors investigated 114 patients by quantitative plasma amino acid analysis. OBJECTIVE: The objective of this study was to collect and analyze epidemiologic and specific clinical data of IEM, especially in small-molecule diseases. MATERIAL AND METHOD: All patients were categorized into 2 major groups. 1) positive diagnoses for IEM 2) negative diagnoses for IEM. The two groups were investigated, studied including statistical analysis. RESULTS: The authors found that most IEM ascertained through plasma amino acid analysis were small-molecule diseases (74.3%) and amino acid disorders consisted of the most frequent disorders. The presented data demonstrated that the ratio of positive diagnoses to all patients studied was 1:8. Epidemiological data showed there were more male than female patients. Onset of diseases occurred predominantly during the first month of age, and was rarely found after 3 years of age. There were histories of consanguinity in half of the IEM patients. The most common presenting symptom was acute metabolic encephalopathy and specific signs for small-molecule disorders included hepatomegaly, unusual urine odor, acidosis, hyperammonemia, alteration of consciousness, and ketosis/ketonuria. These signs or symptoms indicated further metabolic investigations. CONCLUSION: Comparison of the data from Thailand with other countries showed both similarities and differences to the Caucasian population. Thus, further studies in IEM are much needed for the Thai population.

Argininosuccinate synthetase deficiency: mutation analysis in 3 Thai patients.

Remarkable improvements in public health, nutrition, hygiene, and availability of medical services in the last 20 years have significantly reduced infant and childhood mortality in Thailand. Therefore, many rare and previously unidentified genetic disorders, which, in the past, usually led to the death of affected infants before a definitive diagnosis, have now been increasingly recognized. Recently, we identified three unrelated patients from Thailand who suffered from citrullinemia, one of five inherited types of urea cycle disorders. All were diagnosed within their first few weeks of life. Biochemical analyses, including plasma amino acid and urine organic acid profiles, are consistent with argininosuccinate synthetase (ASS) deficiency. Extensive mutation study by direct genomic sequencing of ASS demonstrated a homozygous G117S mutation in one patient and homozygous R363W mutations in the other two families.

The molecular basis of mucopolysaccharidosis type I in two Thai patients.

Two Thai patients diagnosed with Hurler syndrome (mucopolysaccharidosis type 1, MPS I) were found to have no detectable alpha-iduronidase (E.C. 3.2.1.76) activity in leukocytes, while normal Thai children all had significant activity, with a mean of 135 +/- 30 nmol/mg/18h. One patient was heterozygous for A75T (311G>A) and S633L (1986C>T) mutation, previously reported to cause MPS I, together with 9 other heterozygous polymorphisms also found in normal controls. The other patient had the previously described frameshift mutation 252insert C and a new nonsense mutation E299X (983G>T).

Prenatal genetic screening for Down syndrome and open neural tube defects using maternal serum markers in Thai pregnant women.

Maternal serum screening has gained widespread acceptance as a major prenatal screening tool for chromosomal abnormalities in the US and Europe since Merkatz et al described an association between low maternal serum alpha fetoprotein (AFP) levels and increased risk for trisomy 21 in 1984. In 1988, Wald et al proposed a screening program based on maternal age in combination with three biochemical markers--AFP, hCG and unconjugated estriol. This study from January 1996--September 2002 included 1,793 pregnant women (between 14-22 weeks gestation) which were divided into 2 groups--1,083 women > 35 years (60.40%) and 710 women < 35 years (39.60%). A second trimester risk for trisomy 21 > 1 : 270 was considered a positive screen and genetic counseling to discuss risks and benefits of amniocentesis was offered. This study had 1,376 cases (76.7%) with negative screening (not increased risk for DS and NTD), 21 (1.2%) with negative screening (not increased risk for DS only) ; 292 (16.3%) with increased risk for DS; 5 cases (0.3%) with increased risk for DS and elevated AFP; 19 cases (1.1%) with elevated AFP; 33 cases (1.8%) with previous DS only; and 9 cases (0.5%) with previous NTD only. Two percent (2.1%) of the results could not be interpreted either because the test was done too early, too late or were grand multiple pregnancies. This study demonstrated that multiple marker screening offers another option for older women who traditionally have all been considered candidates for amniocentesis.

Inherited metabolic disorders in Thailand.

The study of inborn errors of metabolism (IEM) in Thailand is in its infancy. The majority are clinically diagnosed since there are only a handful of clinicians and scientists with expertise in inherited metabolic disorders, shortage of well-equipped laboratory facilities and lack of governmental financial support. Genetic metabolic disorders are usually not considered a priority due to prevalence of infectious diseases and congenital infections. From a retrospective study at the Medical Genetics Unit, Department of Pediatrics, Siriraj Hospital; estimated pediatrics patients with suspected IEM were approximately 2-3 per cent of the total pediatric admissions of over 5,000 annually. After more than 10 years of research and accumulated clinical experiences, a genetic metabolic center is being established in collaboration with expert laboratories both in Bangkok (Chulabhorn Research Institute) and abroad (Japan and the United States). Numerous inherited metabolic disorders were identified--carbohydrate, amino acids, organic acids, mitochondrial fatty acid oxidation, peroxisomal, mucopolysaccharidoses etc. This report includes the establishment of genetic metabolic center in Thailand, research and pilot studies in newborn screening in Thailand and a multicenter study from 5 institutions (Children's National Center, King Chulalongkorn Memorial Hospital, Pramongkutklao Hospital, Ramathibodi and Siriraj Hospitals). Inherited metabolic disorders reported are fructose-1,6-bisphosphatase deficiency, phenylketonuria, homocystinuria, nonketotic hyperglycinemia, urea cycle defect (arginino succinate lyase deficiency, argininosuccinate synthetase deficiency), Menkes disease, propionic acidemia and mucopolysaccharidoses (Hurler, Hurler-Scheie).

Mitochondrial fatty acid oxidation disorders in Thai infants: a report of 3 cases.

Three infants with documented mitochondrial fatty acid oxidation disorders are described in this report. Case 1. Carnitine/acylcarnitine translocase deficiency. (CACT) (OMIM 212138) A two-day-old male developed sudden cardiac arrest 48 hours postpartum, with a previous history of early death (day 2) in siblings with a history of parental consanguinity; somnolence, inactivity, refusal to suck within 24 h, hepatomegaly, persistent hypoglycemia, hypocalcemia, hyperkalemia and severe metabolic acidosis prior to cardiac arrest. Dried blood spots by tandem mass spectrometry demonstrated 10 x elevation of palmitoylcarnitine, moderate elevation of oleylcarnitine, steroylcarnitine and myristoylcarnitine. Case 2. Medium chain acyl CoA dehydrogenase (MCAD) deficiency. (OMIM 212139) A six-week-old male infant, developed sudden cardiac arrest after contacting a viral illness, resuscitated successfully in the first episode, only to succumb during the second episode, 2 weeks apart. Plasma acylcarnitine via tandem mass spectrometry was reported normal; however, urine organic acids via gas liquid chromatography and mass spectrometry demonstrated characteristic metabolites consistent with MCADD. Case 3. Carnitine deficiency, systemic primary. (CDSP) (OMIM 212140) A one-year-old girl with progressive dyspnea since birth and a history of parental consanguinity. Severe dilated cardiomyopathy with episodes of cardiac decompensations, hepatomegaly, anemia, generalized hypotonia, but no hypoglycemia were demonstrated prior to cardiac arrest. Extremely low carnitine level noted in dried blood spots via tandem mass spectrometry.

Urea cycle disorders in Thai infants: a report of 5 cases.

Urea Cycle Disorders (UCD) is an inborn error of urea synthesis in which ammonium and other nitrogenous precursors of urea accumulate leading to episodic coma and a high mortality rate. Therapy with peritoneal dialysis, essential amino acids or their nitrogen-free analogues has increased survival. The authors report 5 cases of urea cycle disorders, all of whom developed and were rescued from hyperammonemic coma. However, the eventual outcome was quite variable. Argininosuccinate lyase deficiency (ALD) Case 1. A 2 month old male infant, a product of a consanguineous marriage (Suphanburi province); developed poor feeding on day 7, lethargy, convulsion, hepatomegaly and respiratory alkalosis leading to respiratory failure and coma. Hyperammonemia, elevation of glutamic acid and argininosuccinic acid and its anhydrides confirmed the diagnosis of ALD. He is now 9 years old and severely retarded. Case 2. A male infant with history of lethargy, poor feeding on day 3, treated as sepsis and required respiratory support for 6 days; subsequently readmitted at age 2 weeks with vomitting, lethargy, seizure activity and hyperammonemia, and was treated by a local pediatrician in Songkhla province. There was a history of parental consanguinity and he was referred to Siriraj Hospital on day 64 with severe essential amino acid deficiency and acrodermatitis enteropathica with markedly elevated plasma citrulline level. In spite of aggressive treatment; the patient developed sepsis and he expired on day 78. Ornithine transcarbamylase deficiency (OTC) Case 3. An eleven-month-old male infant, the product of a non-consanguineous marriage, developed neonatal onset of hyperammonemia on day 5 after poor feeding, lethargy, hypothermia, seizure, apnea and coma. He was rescued from neonatal hyperammonemic coma on day 9 after aggressive treatment, but expired at eleven months of age after overwhelming sepsis. Case 4. A male infant, sibling of case 3 was referred to Siriraj Hospital on day 8 with hyperammonemia and coma. In spite of intensive genetic counseling given after the birth of their first child with OTC, the couple chose to have another baby without informing any physician. The baby developed vomiting and lethargy on day 2; subsequently hyperammonemia was noted. In spite of aggressive treatment given; hepatic dysfunction, renal failure and disseminated intravascular coagulation defects occurred on day 15. He expired on day 18 after parental permission for discontinuation of all treatment. Argininosuccinate synthetase deficiency (ASS) or Citrullinemia. Case 5. A seven week old female infant, the product of a consanguineous marriage and of Pakistani ethnic origin; developed intermittent vomiting from day 6. Initial diagnoses included ruminations, sepsis and pyloric stenosis for which she was operated on (day 30); however, vomiting continued; subsequently seizures, hyperammonemic coma developed and she was rescued from hyperammonemic coma within 30 hours. Significant elevations of citrulline and L-glutamine were demonstrated. She was discharged in excellent condition to her home in Dubai, the United Arab Emirates.