Histidinaemia: a benign metabolic disorder.

Histidinaemia is a relatively common inherited metabolic disorder with an incidence similar to phenylketonuria. This paper reports the long term outcome of patients diagnosed by newborn screening in the north west of England. Between 1966 and 1990, 108 infants were diagnosed as having histidinaemia by a regional neonatal screening programme (incidence 1:11,083). A further five children were detected following diagnosis in a sibling. Of the 113, nine were lost to follow up. Infants diagnosed before 1981 (n = 47) were placed on a low histidine diet (225 mg/kg/d) for an average period of 21 months (SD 4.5). All patients were reviewed regularly, Griffiths developmental quotients (DQ) were assessed at 2 and 4 years, and WISC-R intelligence quotients (IQ) at 8, 12, and 18 years. IQ data were converted to standard deviation scores (IQ SDS) to account for increasing IQ norms with time. Neither DQ nor IQ correlated with plasma histidine at diagnosis or with the mean plasma histidine throughout life. Growth was normal in all patients. There was no apparent benefit from a low histidine diet in early childhood. In contrast to other studies, there was no excess of clinical symptoms. On the basis of these findings, histidinaemia is a benign metabolic disorder that does not require treatment.     

Histidinaemia: Study of Relation Between Clinical and Biological Findings in 7 Subjects

Seven subjects with raised plasma histidine and low skin histidase levels (histidinaemia) are described: 4 were severely retarded, 2 showing in addition features of an early infantile psychosis (autism); 3 were of normal intelligence. There were no biochemical differences between the two groups.In view of these findings and a study of patients reported in the literature, attention is drawn to the difficulty in making a decision about treatment of a neonate detected by screening and shown to have the biochemical features of histidinaemia. The natural history of the condition is further examined, particularly the question of deterioration at time of seizures or infection.     

Final intelligence in late treated patients with phenylketonuria

Despite neonatal screening programmes, there is still a number of patients with phenylketonuria who are not diagnosed and start treatment late. The question in this study was to evaluate which factors will contribute, other than the quality and duration of dietary treatment, to final outcome in late treated patients with phenylketonuria. We retrospectively analysed the data of 40 patients with phenylketonuria, of whom 2 patients at 35 and 24 years of age had a normal IQ despite never being treated. In 38 patients starting dietary treatment between 0.7 and 7 years of age, mean IQ/DQ at diagnosis was 52.7 (SD=16) (mean age 2.5 years), final IQ (mean age 33.5 years) was 79.0 (SD=16), the difference was highly significant (P < 0.0001). Important factors for the final intelligence in adult late treated patients with phenylketonuria were onset (r=т.46, P < 0.009) and DQ/IQ (r=0.51, P < 0.002) when dietary treatment was started. Thus, in late treated patients with phenylketonuria, in addition to the quality and duration of treatment, the outcome is mainly influenced by the age of starting treatment and also by the intellectual status of the patient. In one of the two patients with normal intelligence, nuclear magnetic resonance spectroscopy showed that brain phenylalanine was undetectable even though blood phenylalanine was 30 mg/dl. A second metabolic disorder may protect these patients from severe brain damage. Conclusion These data indicate that brain damage in untreated or late treated patients with phenylketonuria is influenced by various genetic factors.     

Histidinaemia: screening, diagnosis, clinical picture, therapy

The paper presents the data of mass and selective screening on histidinaemia. The results of complex clinical investigation of 16 patients with histidinaemia are demonstrated. Two forms of the disease were differentiated on the basis of evaluation histidine metabolism. The results of morphological examination of liver biopsy specimens obviously demonstrated significant structural and functional disorders of the liver in histidinaemia.     

Age at diagnosis and abilities in idiopathic hypercalcaemia.

Forty three children aged 6 to 16 years with a documented history of idiopathic infantile hypercalcaemia were assessed on a variety of cognitive and behavioural measures. No relation was found between the age at which hypercalcaemia was diagnosed and subsequent full scale intelligence quotients (IQ) and reading or spelling abilities. Verbal IQ was, however, significantly higher than performance IQ, which had an inverse relation with age at diagnosis. Furthermore, scores for deviant behaviour were found to correlate with age at diagnosis. Thus the characteristic psychological profile of this syndrome may be in part a function of hypercalcaemia during infancy.     

Advances in the diagnosis and treatment of maple syrup urine disease: experience in Galicia (Spain)

INTRODUCTION: Maple syrup urine disease (MSUD) is a rare autosomal recessive disorder caused by an inherited deficiency of branched chain alpha-ketoacid dehydrogenase activity. Accumulation of the amino acids leucine, isoleucine, valine and alloisoleucine and their metabolic products in cells and biological fluids results in severe brain dysfunction. PATIENTS AND METHODS: We present three cases of MSUD diagnosed in Galicia since 2000, the year in which the Extended Newborn Screening Program by tandem mass spectrometry was started in this region. One of the patients was diagnosed on the basis of early clinical presentation and the others by neonatal screening. Enzymatic and molecular studies confirmed two classic cases of MSUD and an intermediate variant. We describe the clinical and biochemical details at confirmation of diagnosis and the long-term outcome of the three patients. Throughout follow-up, all the patients maintained adequate leucine levels, which were near the normal range (mean levels: 220, 177 and 252 micromol/L, respectively). Several moderate metabolic decompensations were observed but leucine levels only occasionally exceeded 1000 micromol/L (one day in two patients). IQ tests were performed in all patients and scores were within the normal range. In view of our results, we believe the following measures are essential to improve the prognosis of MSUD: inclusion of this disease in Expanded Neonatal Screening Programs with early samples (at 2-3 days of life); aggressive treatment in the initial phase and during acute decompensations; strict metabolic control to prevent crises, monitoring of branched-chain amino acids (dried blood spot sample), and maintenance of long term plasma leucine levels below 300 micromol/L.     

EVALUATION OF A NATION-WIDE NEONATAL METABOLIC SCREENING PROGRAMME IN SWEDEN 1965–1979

ABSTRACT. Aim, J. and Larsson. A. (Department of Paediatrics, Karolinska Institute, St. Goran's Children's hospital, and the PKU Section, Department of Bacteriology, National Bacteriological Laboratory, Stockholm, Sweden). Evaluation of a nation-wide neonatal metabolic screening programme in Sweden 1965–1979. Acta Paediatr Scand, 70:601,.–In Sweden, neonatal screening for phenylketonuria was started in 1965 and a total of 1326000 infants were studied up to 1979. During various periods of time, screening was also carried out for galactosaemia, hereditary tyrosinaemia, histidinaemia, and homocystinuria. In screening for phenylketonuria and galactosaemia no false-negative results were obtained and the incidences were 1/30850 and 1/81100, respectively. In screening for hereditary tyrosinaemia only 1 out of 6 patients was identified by screening and the incidence was 1/106 710. Two cases of histidinaemia were detected, which corresponds to an incidence of 1/36 840. Both children developed normally without any treatment. No child with homocystinuria was detected in the screened population of more than 300 000 newborn infants. A screening programme involving phenylketonuria and galactosaemia was considered to be optimal among the tested disorders.     

Maternal phenylketonuria: report from the United Kingdom Registry 1978-97.

BACKGROUND: The effects of maternal phenylalanine on the fetus include facial dysmorphism, microcephaly, intrauterine growth retardation, developmental delay, and congenital heart disease. AIMS: To evaluate the impact of phenylalanine restricted diet in pregnant women with phenylketonuria (PKU) on their offspring. METHODS: Data on virtually all pregnancies of women with PKU in the United Kingdom between 1978 and 1997 were reported to the United Kingdom PKU Registry. The effect of the use and timing in relation to pregnancy of a phenylalanine restricted diet on birth weight, birth head circumference, the presence or absence of congenital heart disease (CHD), 4 year developmental quotient, and 8 year intelligence quotient were examined. RESULTS: A total of 228 pregnancies resulted in live births (seven twin pregnancies were excluded). In 110 (50%), diet started before conception. For this group mean (SD) birth weight was 3160 (612) g, birth head circumference 33.6 (1.9) cm, 4 year DQ 108.9 (13.2), 8 year IQ 103.4 (15.6), and incidence of CHD was 2.4%. In comparison, for those born where treatment was started during pregnancy (n = 91), birth weight was 2818 (711) g, birth head circumference 32.7 (2.0) cm, 4 year DQ 96.8 (15.0), 8 year IQ 86.5 (13.0), and incidence of CHD was 17%. Month-by-month regression analyses suggested that metabolic control by 12-16 weeks gestation had most influence on outcome. CONCLUSIONS: Many features of the maternal PKU syndrome are preventable by starting a phenylalanine restricted diet. Women with PKU and their carers must be aware of the risks and should start the diet before conception, or as soon after as possible.     

Maternal phenylketonuria: report from the United Kingdom Registry 1978-97

Background: The effects of maternal phenylalanine on the fetus include facial dysmorphism, microcephaly, intrauterine growth retardation, developmental delay, and congenital heart disease. Aims: To evaluate the impact of phenylalanine restricted diet in pregnant women with phenylketonuria (PKU) on their offspring. Methods: Data on virtually all pregnancies of women with PKU in the United Kingdom between 1978 and 1997 were reported to the United Kingdom PKU Registry. The effect of the use and timing in relation to pregnancy of a phenylalanine restricted diet on birth weight, birth head circumference, the presence or absence of congenital heart disease (CHD), 4 year developmental quotient, and 8 year intelligence quotient were examined. Results: A total of 228 pregnancies resulted in live births (seven twin pregnancies were excluded). In 110 (50%), diet started before conception. For this group mean (SD) birth weight was 3160 (612) g, birth head circumference 33.6 (1.9) cm, 4 year DQ 108.9 (13.2), 8 year IQ 103.4 (15.6), and incidence of CHD was 2.4%. In comparison, for those born where treatment was started during pregnancy (n = 91), birth weight was 2818 (711) g, birth head circumference 32.7 (2.0) cm, 4 year DQ 96.8 (15.0), 8 year IQ 86.5 (13.0), and incidence of CHD was 17%. Month-by-month regression analyses suggested that metabolic control by 12–16 weeks gestation had most influence on outcome. Conclusions: Many features of the maternal PKU syndrome are preventable by starting a phenylalanine restricted diet. Women with PKU and their carers must be aware of the risks and should start the diet before conception, or as soon after as possible.     

苯丙酮尿症患儿治疗前后脑白质病变的观察

目的：该研究应用MRI观察晚治苯丙酮尿症(PKU)患者治疗前后脑白质病变。方法：确诊为经典型PKU患者19例,进行低苯丙氨酸(PHE)饮食治疗随诊8～16月,治疗前后分别进行了头颅MRI及智商检查。头颅MRI采用常规矢状面、轴面T1W和轴面T2W扫描,对脑白质T2高信号病变按Thompson6级分级法进行分级并评分。观察比较治疗前后脑白质病变的改变。结果：9例晚治PKU患者头颅MRI均存在脑白质病变,其病变主要表现为侧脑室周围及三角区白质等区域存在孤立性斑片状异常T2高信号,治疗前后的平均MRI脑白质T2高信号分级分别为2.59和1.76,治疗前后MRI分级按分数计算,差异有显著性(P<0.01),治疗后T2高信号等级改善。19例均存在不同程度的智力发育落后,在智商改善与T2高信号等级改善可见部分一致关系。血PHE浓度与脑白质病变间有关。结论：晚治PKU患者脑白质病变及智力发育落后具高发生率,低苯丙氨酸饮食治疗降低血苯丙氨酸浓度后脑白质病变及智商均有部分改善,提示PKU患者脑白质病变及智力损害是部分可逆的,PKU患者脑白质改变可能是导致晚治PKU患者智能发育障碍的原因之一。     

Developmental reading disorder: predictors of outcome in adolescents who received early diagnosis and treatment.

In this study of the course of developmental reading disorder, 40 Caucasian children, who were diagnosed and began reading therapy at 7-years-old were followed-up at 14-years-old. A variety of methodological concerns were addressed by careful screening of the subjects, by attempting to include a representative population, by comparing standardized measures statistically at initial and follow-up testing, and by using a homogeneously delayed population. It was found that 40% of the subjects were reading appropriately at follow-up. Improvement and recovery were significantly related to parents' educational status, especially to IQ, and not to gender of subject or to having a speech articulation or hyperactivity problem. It was concluded that for those who receive early diagnosis and treatment of developmental reading disorder (1) IQ may be a good predictor of recovery potential and (2) remedial efforts for the low IQ dyslexic child may be optimal if cognitive therapy is included in addition to reading therapy.     

Stability of Assessment Results of Autistic and Non-Autistic Language-Impaired Children from Preschool Years to Early School Age

The predictability, consistency in group means, and intra-individual stability of developmental quotients and performance IQs were assessed from preschool to school age for 71 autistic children and 71 non-autistic communication-handicapped children, matched on chronological age, sex and initial performance IQ/DQ. DQs/performance IQs at age 4 yrs were found to be highly correlated with performance IQ at age 10 yrs for both groups. Absolute difference scores and group means were also equivalent for both samples, with no difference in patterns of change or the relationship between performance IQ and language status, as measured on the PPVT. Differences between diagnostic groups occurred only for scores on the Vineland Social Maturity Scale and the relationship between these scores and IQ.     

Outcome of the Patients Detected by Newborn Screening in Japan

A follow-up study of the cases detected by a newborn mass-screening program has been performed during 1977–1985 by a collaborative study group. The number of hyperphenylalaninemic patients detected was 148, yielding a calculated incidence of one in 82,000. Of these patients, 102 cases were confired as classical PKU, 37 cases as hyperphenylalaninemia, and 9 cases as biopterine deficiency. The ratio of biopterine deficiency to PKU was about 9%. The incidence of maple syrup urine disease was estimated as one in 580,000, and the incidence of homocystimuria and galactosemia was found to be markedly low. Our survey has accumulated 1,362 cases of histidinemia establishing an incidence of one in 9,000. We have evaluated a large-scale base to study the cad relation of histidinemia to mental development. It seems that low DQ or IQ scores of some histidinemic patients do not correspond to the blood histidine level.     

Verbal dyspraxia in treated galactosemia

Galactosemia is an inborn error of metabolism that causes life-threatening illness a few days after galactose-containing milk is fed to a newborn. Early treatment with a strict lactose-free diet results in rapid improvement, and, until recently, it was thought that the long-term prognosis in such infants was usually good. The speech characteristics of 24 patients treated for galactosemia were examined. Fifty-four percent had the specific speech disorder, verbal dyspraxia. This finding was not related to age at diagnosis, severity of symptoms in the newborn period, or to biochemical control. There may be, however, a relation between dyspraxia and diminished IQ scores observed in the group of patients with dyspraxia judged as "severe." The findings indicate the association of a specific and unusual speech defect with a specific and rare metabolic disorder.     

Massachusetts Metabolic Disorders Screening Program: III. Sarcosinemia

Sarcosinemia has been detected by routine screening of urine for metabolic and transport disorders in Massachusetts. Three infants who had sarcosinemia were detected through the neonatal urine specimen, an observed incidence of 1:350,000. A fourth child had sarcosinemia detected through family screening after his brother was found to have Hartnup disease by neonatal urine screening. These four children with sarcosinemia have plasma sarcosine concentrations ranging from 80 to 603 mumol/L and urine sarcosine from 2.1 to 9.4 mumol/mg of creatinine, findings similar to those reported for persons with sarcosinemia. No treatment has been given. At 3.8 to 15 years of age, the children had normal findings on physical examination and had no specific illnesses. Their full-scale IQ scores ranged from 89 to 111. The oldest child had a learning and emotional disorder, and one other child was emotionally unstable. It was concluded that sarcosinemia as a specific disorder is probably benign and that the mental retardation and dysmorphic features described in some affected persons are likely coincidental with the biochemical defect. The emotional disturbances that were encountered in two children are also probably coincidental but need further attention in this disorder.     

Predicting IQ change in preschoolers with developmental delays.

This study examined IQ change over a 2-year period in 291 young children (mean age 39 months) referred to a pediatric developmental clinic for evaluation of developmental problems. Although correlation between initial and follow-up IQ was very high (0.78), there was also a significant increase in mean IQ score, from 67.12 to 74.06. Moreover, 26% of the subjects showed IQ increase of 16 points or more. Variables making some contribution to IQ change were initial clinical diagnosis, etiology, and intervention. Children diagnosed with a developmental language disorder made significantly greater gains than those diagnosed as mentally retarded. Sex, family status, initial age, and test interval were not significantly correlated with IQ change. We concluded that prediction for individual children is difficult, but that initial diagnosis may be useful in differentially predicting IQ change in young children with developmental delays.     

Pyridoxine-dependent seizures in Dutch patients: diagnosis by elevated urinary alpha-aminoadipic semialdehyde levels.

BACKGROUND: Pyridoxine-dependent seizures (PDS) is a rare, autosomal recessively inherited disorder. Recently alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase deficiency was identified as a major cause of PDS, which causes accumulation of both alpha-AASA and pipecolic acid (PA) in body fluids. METHODS: We studied urinary and plasma alpha-AASA and PA levels in 12 Dutch clinically diagnosed patients with PDS. RESULTS: Alpha-AASA was elevated in both urine and plasma in 10 patients. In these patients plasma PA levels were also elevated but urinary PA levels were normal. DISCUSSION: In all patients with clinically definite PDS, and in most patients with probable or possible PDS, the clinical diagnosis of PDS could be confirmed at the metabolite level. Non-invasive urinary screening for alpha-AASA accumulation provides a reliable tool to diagnose PDS and can save these patients from the classical and potentially dangerous pyridoxine withdrawal test to prove PDS.     

Intellectual development at age 12 years of children with congenital hypothyroidism diagnosed by neonatal screening.

Twenty-seven patients with congenital hypothyroidism diagnosed by neonatal screening were examined at the age of 12 years. The 12 patients with severe hypothyroidism at diagnosis (thyroxine < 2 micrograms/dl (< 26 nmol/L), and area-of-the-knee epiphyses < 0.05 cm2 had a lower IQ than the 15 patients with less severe hypothyroidism (mean +/- SD, 89 +/- 17 vs 104 +/- 10; p < 0.007). Comparisons of patients and siblings confirm that this difference was due to the severity of hypothyroidism.     

Outcome of early and long-term management of classical maple syrup urine disease

The outcome of 8,400 treatment days in the lives of four patients with classical maple syrup urine disease (MSUD) (present ages: 1 3/12, 5 7/12, and 8 11/12 years) are described. Each diagnosis was made by clinical signs rather than by newborn screening. Acute-phase treatment beginning on the 11th day of life comprised peritoneal dialysis, intravenous lipid, and early intestinal alimentation. Mean age at discharge from hospital was 29 days. There were 16 readmissions to the hospital for the group (89 days, 1.05% treatment days) without any serious neurologic symptoms. The mean level of plasma leucine for the group (for levels below 1 mM) during treatment was 0.42 mM (normal for age range, 0.077 +/- 0.021 mM [mean +/- SD]). Plasma leucine exceeded 1 mM during 1.02% of treatment days (representing 8.6% of 1,042 measurements. Mean levels of plasma valine and isoleucine were 60% and 70% of the plasma leucine value for the group. Tolerance for dietary leucine did not exceed 620 mg/day in any patient. Somatic growth was normal and the mean current IQ/development quotient (DQ) score is 101 (range 89 to 117); the three oldest patients attend regular schools. A characteristic EEG pattern resembling the teeth of a comb was observed in three patients during the acute phase in the newborn period but not during long-term treatment. These results were obtained in an ambulatory program with home visiting.