The Italian screening program for primary congenital hypothyroidism: actions to improve screening, diagnosis, follow-up, and surveillance

The Italian screening program for primary congenital hypothyroidism (CH) is an integrated system including neonatal screening, diagnosis, treatment, follow-up, and nationwide surveillance of the disease. The aim of the Italian screening program for CH is to identify not only babies with severe permanent CH (core target), but also babies with mild persistent and transient forms of CH who could have a benefit from an early replacement therapy (secondary target). In the last years, despite the important results obtained in terms of standardization of screening and follow-up procedures, it has become clear the need of optimizing the program in order to harmonize the screening strategy and the screening procedures among Regions, and to improve the diagnostic and therapeutic approach in all affected infants. On the basis of available guidelines, the experience of the Italian screening and clinical reference centers, and the knowledge derived from the nation-wide surveillance activity performed by the Italian National Registry of Infants with CH, the Italian Society for Pediatric Endocrinology and Diabetology together with the Italian Society for the Study of Metabolic Diseases and Neonatal Screening and the Italian National Institute of Health promoted actions aimed at improving diagnosis, treatment, follow-up and surveillance of CH in our country. In this paper the most important actions to improve the Italian screening program for CH are described.

Phenotypic variability, neurological outcome and genetics background of 6-pyruvoyl-tetrahydropterin synthase deficiency

This study aimed to investigate the clinical variability and factors implied in the outcome of 6-pyruvoyl-tetrahydropterin synthase deficiency (PTPSd). Biochemical and clinical phenotype, treatment variables, and 6-pyruvoyl-tetrahydropterin synthase (PTS) genotype, were explored retrospectively in 19 Italian patients (12 males and 7 females, aged 4 months to 33 years). According to the level of biogenic amines in cerebrospinal fluid (CSF) at the diagnosis, the patients were classified as mild (6) (normal level) or severe (13) (abnormal low level) form (MF and SF, respectively). Blood Phe ranged from 151 to 1053 micromol/l in MF (mean +/- SD: 698 +/- 403) and 342-2120 micromol/l in SF (mean +/- SD: 1175 +/- 517) (p = 0.063). Patients with MF showed a normal neurological development (a transient dystonia was detected in one), while all SF patients except one presented with severe neurological impairment and only four had a normal neurological development. The outcome of the SF was influenced by the precocity of the treatment. Serial CSF examinations revealed a decline of 5-hydroxyindolacetic acid in MFs and an incomplete restoration of neurotransmitters in SFs: neither obviously affected the prognosis. PTS gene analysis detected 17 different mutations (seven so far unreported) (only one affected allele was identified in three subjects). A good correlation was found between genotype and clinical and biochemical phenotype. The occurrence of brain neurotransmitter deficiency and its early correction (by the therapy) are the main prognostic factors in PTPSd.

Tyrosine hydroxylase deficiency presenting with a biphasic clinical course

Tyrosine hydroxylase deficiency, a cause of the autosomal recessive form of L-DOPA responsive dystonia, has been associated with a broad spectrum of movement disorders and clinical courses. We describe a new patient presenting with an early onset spastic paraplegia who later developed a progressive generalized dystonic-dyskinetic syndrome. He markedly improved with a very low dosage of L-DOPA/carbidopa, while higher dosages were not tolerated. Two novel mutations (p.G414R/p.L510Q) were detected in the TH gene.

The pathogenesis of the white matter abnormalities in phenylketonuria. A multimodal 3.0 tesla MRI and magnetic resonance spectroscopy (1H MRS) study

OBJECTIVE

To gain insights into the nature and pathogenesis of white matter (WM) abnormalities in PKU.

METHODS

Thirty-two patients with phenylalanine hydroxylase deficiency (21 with early and 11 with late diagnosis and treatment) and 30 healthy controls underwent an integrated clinical, neuroimaging (3.0 T MRI, diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI)) and neurochemical (1H MRS) investigation.

RESULTS

All patients had white matter abnormalities on T2-weighted (T2W) and fluid-attenuated inversion recovery (FLAIR) scans; parietal white was consistently affected, followed by occipital, frontal and temporal white matter. T1-weighted hypointense alterations were also found in 8 of 32 patients. DWI hyperintense areas overlapped with those detected on T2W/FLAIR. The apparent diffusion coefficient (ADC) was reduced and correlated inversely with severity of white matter involvement. Fractional anisotropy index, eigenvalues lambda(min), lambda(middle), lambda(max) obtained from DTI data, and the principal brain metabolites assessed by 1H MRS (except brain phenylalanine (Phe)) were normal. Brain Phe peak was detected in all but two subjects. Brain and blood Phe were strictly associated. Blood Phe at the diagnosis, patient's age, and concurrent brain Phe independently influence white matter alteration (as expressed by conventional MRI or ADC values).

CONCLUSIONS

(a) MRI abnormalities in phenylketonuria are the result of a distinctive alteration of white matter suggesting the intracellular accumulation of a hydrophilic metabolite, which leaves unaffected white matter architecture and structure. (b) White matter abnormalities do not seem to reflect the mechanisms involved in the derangement of mental development in PKU. (c) Our data do not support the usefulness of conventional brain MRI examination in the clinical monitoring of phenylketonuria patients.

Treatment monitoring of brain creatine deficiency syndromes: a 1H- and 31P-MR spectroscopy study

BACKGROUND AND PURPOSE

Brain creatine (Cr) deficiencies (BCr-d) are rare disorders of creatine biosynthesis and transport. We performed consecutive measures of total Cr (tCr) and of its phosphorylated fraction, phosphocreatine (PCr), in the brains of children affected by Cr synthesis defects during a long period of therapy. The aim was to identify the optimal treatment strategy for these disorders.

MATERIALS AND METHODS

Two patients with guanidinoacetate methyltransferase defect (GAMT-d) were treated with different amounts of Cr and with diet restrictions aimed at reducing endogenous guanidinoacetate (GAA) synthesis. Three patients with arginine:glycine amidinotransferase defect (AGAT-d) were treated with different Cr intakes. The patients' treatments were monitored by means of (1)H- and (31)P-MR spectroscopy.

RESULTS

Cr and PCr replenishment was lower in GAMT-d than in AGAT-d even when GAMT-d therapy was carried out with a very high Cr intake. Cr and especially PCr replenishment became more efficient only when GAA blood values were reduced. Adenosine triphosphate (ATP) was increased in the baseline phosphorous spectrum of GAMT-d, and it returned to a normal value with treatment. Brain pH and brain P(i) showed no significant change in the AGAT-d syndrome and at any Cr intake. However, 1 of the 2 GAMT-d patients manifested a lower brain pH level while consuming the GAA-lowering diet.

CONCLUSIONS

AGAT-d treatment needs lower Cr intake than GAMT-d. Cr supplementation in GAMT-d treatment should include diet restrictions aimed at reducing GAA concentration in body fluids. (1)H- and especially (31)P-MR spectroscopy are the ideal tools for monitoring the therapy response to these disorders.

The spectrum of phenylalanine variations under tetrahydrobiopterin load in subjects affected by phenylalanine hydroxylase deficiency

A fall in blood phenylalanine (Phe) after tetrahydrobiopterin (BH(4)) administration is a common trait in phenylalanine hydroxylase (PAH, EC 1.14.16.1) deficiency (McKusick 261600). To explore the extent and biological correlates of this phenomenon we studied: (a) the spectrum of BH(4) response in patients with PAH deficiency; (b) the variability of BH(4) response according to the severity of the biochemical phenotype; and (c) the variability of the response to BH(4) in subjects with the same genotype. Fifty PAH-deficient subjects (age 1 month-35 years) were enrolled for the study (5 with mild hyperphenylalaninaemia (MHPHE), 15 with mild phenylketonuria (MPKU) and 30 with classic phenylketonuria (CPKU) and underwent an identical schedule of blood samplings 24 h before and after oral BH(4) challenge (6(R)-BH4, 20 mg/kg per day), leaving Phe intake unchanged. The effect of BH(4) on blood Phe concentration was evaluated according to the percent decrease of Phe during the 24 h following the challenge (criterion a), and as variation exceeding the individual variability of blood Phe (criterion b). The number of BH(4)-responders according to criterion b was 31 (including all the 14 detected by criterion a): 17 out of 30 CPKU (57%), 9 out of 15 MPKU (60%), and all the MHPHE subjects (chi(2) = 3.45, df = 2, p = 0.178). The effect of BH(4) showed a large interindividual variability unrelated to diagnostic classification, basal value of blood Phe, maximum percentage of Phe reduction, Phe intake, and genotype. Some inconsistencies were found in patients with identical genotype. The first responsive case homozygous for the severe R408W mutation was found. Two new mutations, Y387X and G352C, were identified (the former was BH(4)-responsive), and the responsiveness of three already reported mutations (R261Q, D338Y, T92I) was substantiated.

Executive function impairment in early-treated PKU subjects with normal mental development

Executive functions were studied in 14 early and continuously treated PKU subjects (age 10.8 years, range 8-13) in comparison with controls matched for IQ, sex, age and socioeconomic status. Brain MRI examination was normal in all PKU patients. Neuropsychological evaluation included Wisconsin Card Sorting Test, Rey-Osterreith Complex Figure Test, Elithorn's Perceptual Maze Test, Weigl's Sorting Test, Tower of London, Visual Search and Motor Motor Learning Test. Whatever the IQ, PKU subjects performed worse than controls in tests exploring executive functions. Subgrouping the PKU subjects according to the quality of dietary control for the entire follow-up period (using 400 micromol/L as cut-off value for blood phenylalanine (Phe) concentration) showed that patients with worse dietary control performed more poorly than both the PKU group with the best dietary control and the control group. However, a mild impairment of executive functions was still found in PKU patients with a good dietary control (Phe <400 micromol/L) compared to controls. Concerning the PKU group as a whole, no linear correlation was found between neuropsychological performance and historical and concurrent biochemical parameters. We conclude that (a) PKU patients, even when treated early, rigorously and continuously, show an impairment of frontal lobe functions; (b) a protracted exposure to moderately high levels of Phe can affect frontal lobe functions independently of the possible effect of the same exposure on IQ; (c) in order to reduce the risk of frontal lobe dysfunction, the target of dietary therapy should be to maintain blood Phe concentration below 400 micromol/L.

Autosomal dominant GTP-CH deficiency presenting as a dopa-responsive myoclonus-dystonia syndrome

The authors report a kindred in which GTP-CH deficiency resulted in a myoclonus-dystonia syndrome. The proband, a 17-year-old boy, presented with early-onset myoclonus and later, dystonia and bradykinesia. Blood prolactin was increased and CSF homovanillic acid, 5-hydroxyindoleacetic acid, and biopterin were all reduced. L-Dopa/carbidopa administration resulted in clinical improvement. In the paternal branch, the grandfather and three relatives had myoclonus-dystonia and resting or postural tremor of limbs. The authors found a missense mutation in the exon 6 of GCH-1 gene (K224R).

Automated high-performance liquid chromatographic method for the determination of guanidinoacetic acid in dried blood spots: a tool for early diagnosis of guanidinoacetate methyltransferase deficiency

A new automated method for the assay of guanidinoacetic acid (GAA) in dried blood spot (DBS) on filter paper is reported. The method, based on reversed-phase (RP)-HPLC, precolumn derivatisation with benzoin and fluorescence detection, has shown good precision and sensitivity and requires only minimal sample handling. The validity of the method was demonstrated by analysing the neonatal blood spot of a patient affected by guanidinoacetate methyltransferase (GAMT) deficiency. GAA concentration was found to be nearly 12-fold higher than the mean control value. We propose this method as an inexpensive and widely applicable tool for the diagnosis of GAMT deficiency.

Two new severe mutations causing guanidinoacetate methyltransferase deficiency

Primary disorders of creatine metabolism have been only recently described. We report new molecular and biochemical findings obtained from a child affected by guanidinoacetate methyltransferase deficiency. This patient presented with neurological regression, epilepsy, and a movement disorder during the first year of life. HPLC analysis showed high concentrations of guanidinoacetic acid in urine, plasma, and CSF. Molecular analyses of cDNA and genomic DNA revealed two novel mutations, a G insertion following nucleotide 491 of the cDNA (c.491insG) in exon 5 and a transversion at nt -3 in intron 5 (IVS5-3C>G). The c.491insG mutation causes a frameshift and a premature stop codon at the end of the exon. The IVS5-3C>G mutation prevents the splicing of the last exon of the gene precluding the complete maturation of the transcript and, most likely, causes rapid degradation of the mRNA.

Brain creatine depletion: guanidinoacetate methyltransferase deficiency (improving with creatine supplementation)

The authors describe an Italian child with guanidinoacetate methyltransferase deficiency, neurologic regression, movement disorders, and epilepsy during the first year of life. Brain MRI showed pallidal and periaqueductal alterations. In vivo 1H-MRS showed brain creatine depletion. The assessment of guanidinoacetic acid concentration in biologic fluids confirmed the diagnosis. Clinical, biochemical, and neuroradiologic improvement followed creatine supplementation.

Clinical significance of brain phenylalanine concentration assessed by in vivo proton magnetic resonance spectroscopy in phenylketonuria

Recent studies using in vivo proton magnetic resonance spectroscopy (1H MRS) have suggested that plasma phenylalanine (Phe) may not be a reliable indicator of brain Phe level in subjects with phenylketonuria (PKU). Interindividual variation in cerebral Phe can contribute to the phenotypic variability of the disease. We report the results of the direct assessment of brain Phe by 1H MRS in 10 off-diet PKU patients (aged 15.5-30.5 years), 4 detected and treated early, 6 late. In a single patient, brain Phe was evaluated before and 15 days after diet discontinuation. FLAIR MRI and 1H MRS were performed in the same setting by a 1.5 T clinical MR scanner. MR images were scored according to the extent of the lobar white-matter hyperintensity. Brain 1H MRS Phe signal (resonating at 7.36 ppm) was evaluated as a ratio to the creatine+phosphocreatine signal. Brain Phe was correlated with clinical, biochemical and MRI findings. Results were as follows. (1) An abnormal concentration of brain Phe was detected in all 10 PKU subjects (ranging from 0.030 to 0.074), associated with a wide interindividual variability of concurrent plasma Phe (ranging from 724 to 2800 micromol/L). (2) In late-detected subjects, brain Phe concentration correlated with clinical phenotype better than did plasma Phe. The discrepancy between brain and plasma Phe was relevant from a clinical point of view in two cases: in one, a late-detected patient with normal mental development, a high level of plasma Phe was associated with a relatively low concentration of brain Phe; in the other, a late-detected subject with severe neurological impairment, a very high level of brain Phe was associated with plasma Phe compatible with the diagnosis of mild PKU. (3) White-matter alterations were detected in all patients. FLAIR MRI sequences disclosed an involvement of optic chiasma and tracts in 7 subjects. No correlation was found between white-matter alterations and concurrent brain Phe concentrations. (4) In the only case assessed under different intake of Phe, the relevant increase of brain Phe paralleled the concurrent increase of plasma Phe, showing that 1H MRS can be a useful tool in evaluating the individual vulnerability of PKU patients to different values of plasma Phe.

Automated high-performance liquid chromatographic method for the determination of homocysteine in plasma samples

Plasma homocysteine determination is essential for the diagnosis of inborn errors of metabolism of sulfur amino acids and is achieving considerable importance as a possible risk marker in vascular occlusive pathology. The aim of this study was therefore to develop a fast and sensitive method to assay total and free homocysteine and total and free cysteine in plasma samples, using an automated precolumn sample pretreatment including reduction with 2-mercaptoethanol, carboxymethylation of free thiols and derivation with o-phthalaldehyde. The chromatographic separation was accomplished in 7 min, the within-run and between-run R.S.D.s were all less than 4.3%, the response was linear in the range 0.4-150 microM for homocysteine and 4-1000 microM for cysteine and the mean recoveries were higher than 96%. Moreover, with minimal modification, the method allowed the evaluation of methionine, another important marker of transsulfuration and remethylation defects. The method was applied to the diagnosis of inborn errors involving sulfur amino acids metabolism and to detect mild hyperhomocysteinemia.

Clinical and subthreshold eating disorders: case detection in adolescent schoolgirls

The point prevalence of eating disorders was investigated in schoolgirls from lower socio-economic classes and a method of case detection was tested. A two-stage procedure (self-report measures and interviews) was followed. All girls meeting at least one of the following three criteria were recruited as possible cases: EAT > or = 30, BMI < 17.5, BMI < 19 or > 24 and EAT > or = 20. The Mann-Whitney's two-tailed test and the chi-square test were used to assess the significance of differences between the possible cases and the others and between the false positives and the cases. A diagnosis of eating disorder was made for 24 subjects (8.1%): 5 (1.7%) with bulimia nervosa and 19 (6.4%) with eating disorders not otherwise specified (EDNOS). Of the 24 girls with eating disorders only 16 had high EAT40 scores (> or = 30). The other 8 cases were identified by the help of other criteria that proved to be useful. Furthermore we found data on five self-report instruments (EAT40, EDI, SCANS, SCL90, SEI). On almost all the scales, the possible cases obtained scores significantly different from the others. On the contrary, we did not find any instrument able to discriminate between false positives and cases.

Automated method for the measurement of amino acids in urine by high-performance liquid chromatography

An automatic and sensitive HPLC method for the determination of primary and secondary amino acids included cystine and homocystine in urine samples is described. After a simple ultrafiltration, urine samples were subjected to reduction of disulfides, carboxymethylation of free thiols and double precolumn derivatization with o-phthalaldehyde-3-mercaptopropionic acid and 9-fluroenylmethyl chloroformate. All reactions were fully automated by means of an injector programme and were accomplished in 10 min. Since urine samples contain a large number of amino compounds, a good resolution was required. By optimization of the conditions, separation of 40 amino acids in 92 min was achieved. The recovery of amino acids ranged from 83% for TRP to 105% for CIT. The within-run and between-run R.S.D.s of urinary amino acid concentrations were below 10% for most amino acids except for HYL, LYS and ORN. The method was applied to the diagnosis of genetic disorders of amino acid metabolism.

Biochemical, clinical and neuroradiological (MRI) correlations in late-detected PKU patients

Brain magnetic resonance imaging (MRI) was performed in 17 late-detected PKU patients (aged 2.8-25 years). Twelve subjects had been treated late (0.7-4.5 years), and 5 not at all. Four were still on diet when the study was performed. Mental development was normal in 4 subjects, mildly retarded in 6, and moderately or severely retarded in 7. None had exhibited mental or neurological deterioration. On MRI examination a symmetrical increase of T2-weighted signal in the periventricular white matter was found in all patients, although to different degrees. Concomitant signal decrease on the T1-weighted sequences was detected in 9 patients. Ten subjects showed focal white-matter abnormalities. A variable degree of cortical and subcortical atrophy was found in 12 subjects, and asymmetry of lateral ventricles in 4. White-matter involvement correlated with phenylalanine concentrations during the year preceding (rs = 0.5706; p < 0.02) and at the time of (rs = 0.6182, p < 0.01) the investigation. Cortical and subcortical atrophy correlated with the patient's age (rs = 0.5889, p < 0.02, and rs = 0.5929, p < 0.02, respectively). We conclude that late-detected PKU patients showed the same MRI abnormalities reported in early-treated subjects and in subjects who underwent neurological deterioration; white-matter abnormalities possibly result from the recent exposure to high phenylalanine concentrations; in late-detected PKU subjects cerebral atrophy could be the late result of chronic exposure to high phenylalanine concentrations.

Visual, auditory, and somatosensorial evoked potentials in early and late treated adolescents with phenylketonuria

Pattern reversal visual, auditory, and somatosensorial evoked potentials were recorded in two groups of phenylketonuric (PKU) adolescents after protracted exposition to high concentrations of phenylalanine following diet discontinuation. The first group consisted of 11 early treated (before age 3 months) PKU patients (ET-PKU); the second group consisted of 11 late detected (after age 8 months), symptomatic, PKU subjects (LT-PKU). Despite the relevant lag between the two groups in mental development and neurological status, no clear-cut difference in evoked potentials could be detected. Only the wave I latency of the brainstem auditory evoked potentials (BAEPs) was significantly shorter in ET- versus LT-PKU children. The P100 latency, I-V interpeak latency (IPL), and I-III IPL seem to discriminate the less severe form of PKU (ET-PKU type 3) from the most severe forms, ET-PKU type 1 plus 2 and LT-PKU. No correlations were found between clinical, biochemical, and neurophysiological parameters. The present data suggest that evoked potentials technique is of limited sensitivity in detecting central nervous system (CNS) alterations in PKU adolescents after diet discontinuation.

Neuroradiological (MRI) abnormalities in phenylketonuric subjects: clinical and biochemical correlations

A clinical, biochemical and neuroradiological (MRI) study was performed in 22 hyperphenylalaninemic patients detected by neonatal screening and early treated (Group A; 5-23 years old, 13 females and 9 males) and in 5 late detected, symptomatic subjects (Group B; 9-23 years old, 3 females and 2 males). The screening subjects were clustered in a Group A1 (10 on diet patients), and a Group A2 (12 after end of diet patients). On MRI examination (1.5-T magnet, SE T1-weighted 530/22/2, T2-weighted 2400/15-90/1 sequences, SL 6 mm, gap 1.8) a symmetrical increase of the T2-weighted signal in the periventricular white matter was found in all patients. The periatrial white matter was always involved, the occipital region was affected in 22 cases, the frontal region in 16. Concomitant signal decrease on the T1-weighted sequences in the same areas with the highest signal intensity on the T2-weighted scans was found in 7 patients (in 3 out of 12 Group A2 and in 4 out of 5 Group B patients). In 6 Group A and in 3 Group B subjects a variable degree of cortical and subcortical atrophy was detected. A significantly positive correlation was found between white matter involvement and the degree of recent exposition to high PHE values. This correlation was also confirmed when only Group A was examined. Moreover, a significant difference in neuroradiological involvement was found between Group A1 and Group A2 subjects, but not between Group A2 and Group B subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA elution and amplification by polymerase chain reaction from dried blood spots

A quick, sensitive and easily automatizable method for PCR amplification of genomic DNA eluted from dried blood spots is described. DNA is eluted from a 3-mm spot routinely used for neonatal screening of inherited diseases either by boiling or by sonication. A preliminary and brief spot-autoclaving step is mandatory to ensure optimal and reproducible PCR amplifications. Only 1% of the eluted DNA is required for PCR analysis allowing the execution of multiple genetic tests on the same blood spot. The method has been successfully applied to the detection of a known phenylketonuria-causing mutation and will facilitate the analysis of the genetic repository provided by Guthrie's cards stored in neonatal screening laboratories.

The pathobiochemistry of uremia and hyperargininemia further demonstrates a metabolic relationship between urea and guanidinosuccinic acid

To better understand the biosynthesis of guanidinosuccinic acid, we determined urea, arginine, and guanidinosuccinic acid levels in nondialyzed uremic and hyperargininemic patients. These substances were also determined during several years of therapy in one hyperarginiemic patient. Interrelationships of guanidinosuccinic acid levels with their corresponding urea and arginine levels were assessed by linear correlation studies. In uremic patients, a significant positive linear correlation (r = .821, p less than .001) was found between serum urea and guanidinosuccinic acid levels A significant positive linear correlation was also found between serum urea levels and urinary guanidinosuccinic acid levels (r = .828, P less than .001), but not between serum arginine levels and urinary guanidinosuccinic acid levels in hyperargininemic patients. In the intrahyperargininemic patient study, a similar significant positive correlation was found between serum urea levels and the corresponding urinary guanidinosuccinic acid levels (r = .866, P less than .001); the correlation between serum arginine levels and the corresponding urinary guanidinosuccinic acid levels was smaller. The presented analytical findings in uremic and hyperargininemic patients clearly demonstrate a metabolic relationship between urea and guanidinosuccinic acid.

Prolactin responses to domperidone in chronic schizophrenia

The prolactin response to 20 mg of domperidone, a peripheral dopamine receptor antagonist, was evaluated in a group of 17 male, drug-free, elderly, chronic schizophrenic patients and 8 age-matched male normal control subjects. Both groups of subjects were receiving a variety of nonpsychotropic medications not known to affect the prolactin response to dopamine receptor antagonists. Basal plasma prolactin levels did not differ between the two groups. However, the prolactin response following domperidone was significantly greater in the schizophrenic patients, although plasma domperidone levels did not differ between the two groups. This effect is opposite to the previously reported effect of domperidone in young schizophrenic patients compared with age-matched control subjects (Nerozzi et al., 1990). The prolactin response to domperidone was markedly smaller in the old compared with the young normal control subjects, whereas the young and old schizophrenic patients had identical responses. Possible explanations for these results are considered, especially the possibility of abnormalities in the release of dopamine and pituitary D2 dopamine receptors in the elderly schizophrenic patients compared with age-matched normal control subjects.

TRH test and the continuous dopaminergic stimulation in complicated Parkinson's disease

Marked, disabling fluctuations in motor performance (on-off phenomena) appear after chronic L-Dopa therapy in Parkinson's disease (PD). Intravenous infusion of L-Dopa greatly reduces these motor fluctuations, but it is not reliable as a chronic treatment. Therefore, infusion of the potent, water-soluble dopaminergic agonist lisuride has been tested. However, many patients did not respond to infusion of lisuride alone, and no clinical parameter is known to correlate with the lacking response. In order to study this problem, we performed the TRH test (200 micrograms i.v.) in 8 PD patients with severe motor fluctuations; before and during lisuride subcutaneous infusion, we measured PRL and TSH responses to TRH. Both PRL and TSH receive an inhibitory control from dopaminergic receptors on pituitary cells, whereas they are stimulated by TRH. The TRH test, given during lisuride infusion, allows an indirect evaluation of the 'brake function' of the dopaminergic system on anterior pituitary, i.e. of dopaminergic receptor sensitivity in vivo. In our study, TRH induced a significant TSH rise in all PD patients, before and during lisuride infusion. Moreover, the lisuride responders (i.e. patients showing constant 'on' period during lisuride infusion, 4 patients) showed a significant lower TSH response as compared to nonresponders. PRL levels followed the same trend without reaching statistical significance. These data are compatible with the presence, in the two groups, of a different pituitary dopaminergic sensitivity which would suggest the presence of pharmacodynamic factors associated with the lacking response to intravenous lisuride infusion.

Mitochondrial DNA mutation in an Italian family with Leber hereditary optic neuropathy

Mitochondrial (mt) DNA from a Southern Italian family with Leber hereditary optic neuropathy was analyzed for the presence of the reported mutation at position 11778 of the ND4 subunit gene. The point mutation was found in mt DNA extracted from peripheral blood in all members of the family with the exclusion of the father, and was present in a homoplasmic fashion, despite the phenotypic heterogeneity of disease presentation among family members.

Rapid and sensitive high-performance liquid chromatographic method for the analysis of tryptophan, tyrosine and phenylalanine in biological samples

In order to overcome problems related to the determination of free tryptophan in biological fluids using conventional methods, we have developed an accurate and reliable procedure based on a specific pretreatment of samples followed by a very rapid and sensitive reversed-phase high-performance liquid chromatographic analysis. The pretreatment consists of adding to the samples of a very low amount of 3 M phosphate buffer to maintain pH in the physiological range followed by ultrafiltration. The precision, reproducibility and sensitivity of our method were also evaluated. The recovery of each amino acid was greater than 92%. The use of a microbore column allows the detection of up to 0.2 pmol/microliter of amino acid. The method has been applied to the analysis of samples obtained from 25 normal and 10 phenylketonuric subjects.

The development of auditory and visual evoked potentials in early treated phenylketonuric children

Brain-stem auditory evoked potentials (BAEPs) and flash visual evoked potentials (F-VEPs) were gathered from 8 early treated phenylketonuric (PKU) children in a prospective longitudinal investigation during the 1st to the 12th months after birth. No consistent differences were found in the wave morphology of evoked potentials in PKU children from that of age-matched controls. Studying the latency of some components showed that in BAEPs, wave I latency was similar to control values for the whole year, but that the I-V interpeak mean latency (I-V IPL) was always significantly longer than in controls. In F-VEPs wave N1 latency was significantly longer than in controls only at 1-2 months of age, but returned to control values at 3-4 months (when all children were on dietary therapy) and remained in this range up to the 12th month. The mean latency of the P2 wave of flash VEPs was always significantly longer in PKU children than in controls. These results show that relevant alterations in evoked potentials may be found in PKU children several months after starting dietary therapy. This suggests that information processing in the brain may be impaired for a long time, due to abnormal metabolic conditions between birth and the onset of dietary therapy.

Plasma prolactin response to domperidone in acute schizophrenia and schizophreniform illness

The prolactin (PRL) response to 20 mg of domperidone, a peripheral dopamine (DA) blocking agent, was evaluated in a group of 16 drug-free, acute, young schizophreniform and schizophrenic males and in a group of age-matched normal males. Although basal plasma PRL levels were normal, the PRL responses following domperidone were blunted in both patient groups. The PRL response was more blunted in the schizophreniform patients than in the schizophrenic patients. Possible explanations for these results include pharmacokinetic factors or abnormalities of the pituitary D2 DA receptors.

Simultaneous high-performance liquid chromatographic determination of amino acids in a dried blood spot as a neonatal screening test

A new screening test on dried blood spots for inherited disorders of amino acid metabolism using reversed-phase high-performance liquid chromatography (RP-HPLC) is described. The method allows the simultaneous analysis of fourteen different amino acids; among these, seven whose blood levels are increased in the most important amino acid disorders have been determined. The procedure requires a preliminary extraction of the amino acids from 9-mm autoclaved dried blood spots by sonication in phosphate-buffered saline. A precolumn o-phthaldialdehyde-3-mercaptopropionic acid derivatization is then followed by analysis of the amino acids by RP-HPLC. Blood-spots levels of histidine (His), tyrosine (Tyr), valine (Val), methionine (Met), isoleucine (Ile), phenylalanine (Phe) and leucine (Leu) can be determined in a single 15-min run, including column washing and regeneration. The minimum detectable amount of each amino acid is 0.5 pmol with a linear dose-response range between 1 and 10 microM. The recovery for all amino acids is greater than 70% except for Met (66%). Up to 20,000 samples/year can be processed on a single automated analytical line resulting in an estimated cost of about US$ 0.25/sample. The multiple diagnostic capacity, the low cost and the possibility of complete automation of the method make it suitable for primary perinatal screening of amino acid disorders.

Cytofluorometric analysis of lymphocyte subsets in thyroid aspirates from patients with autonomously functioning nodules

A microscale method, based on two-colour dye immunolabelling and flow sorting cytofluorometry, was used to characterize lymphocyte subsets in thyroid tissue specimens obtained by fine-needle aspiration (FNA) in 21 patients with autonomously functioning thyroid nodule (AFTN) and five patients with cold thyroid nodule (CTN). Inversion of the ratio between CD4+ and CD8+ lymphocytes, due to a relative increase of CD8+ cells, was found among intrathyroidal lymphocytes in AFTN patients. The abnormal lymphocyte subset distribution was not observed in the peripheral blood of the same group of patients. In patients with CTN the lymphocyte subset distribution was normal, both in the thyroid and in the peripheral blood. In AFTN patients, a significant correlation was observed between the decrease of intrathyroidal CD4+/CD8+ ratio and the increase of plasma thyroid hormone levels. Whether the immunological abnormalities found in AFTN could play a pathogenetic role in the clinical presentation and outcome of the disease remains to be established. The FNA-applied micromethod used in this study could be extended as a routine investigation to characterize the immunogenic substrate of thyroid disorders.

Guanidino compound analysis as a complementary diagnostic parameter for hyperargininemia: follow-up of guanidino compound levels during therapy

The aim of this collaborative study was to investigate whether guanidino compound analyses in the biologic fluids can be used as a complementary diagnostic parameter for hyperargininemia. Guanidino compounds were determined in the biologic fluids of all known living hyperargininemic patients using a cation exchange chromatographic system with a fluorescence detection method. The serum arginine, homoarginine, alpha-keto-delta-guanidino-valeric acid, argininic acid, and N-alpha-acetylarginine levels of all the hyperargininemic patients are higher than the normal range. Similar increases were seen for the urinary excretion of alpha-keto-delta-guanidinovaleric acid and argininic acid. Untreated hyperargininemic patients have the highest guanidino compound levels in cerebrospinal fluid. However, even under therapy, the arginine, homoarginine, alpha-keto-delta-guanidinovaleric acid, and argininic acid levels in cerebrospinal fluid are still increased. Protein restriction alone is not sufficient to normalize the hyperargininemia, but protein restriction together with supplementation of essential amino acids with or without sodium benzoate decreases further the arginine levels. However, whereas the argininemia can be normalized, the catabolites of arginine are still increased. We conclude that the urinary amino acid levels may remain normal in hyperargininemia, whereas consistent increases of the guanidino compounds are observed. Thus, guanidino compound analyses can be used as a complementary biochemical diagnostic parameter for hyperargininemia. Although the argininemia can be normalized by therapy, the levels of the catabolites of arginine are still elevated.

Prolactin and growth hormone responses to growth hormone-releasing hormone in acute schizophrenia

Growth hormone (GH), and prolactin (PRL) responses to the administration of growth hormone-releasing hormone (GHRH) (1 microgram/kg) were evaluated in a group of 18 drug-free, acute, young male schizophrenics and in a group of age-matched normal controls. Cortisol responses were also evaluated. No difference in mean plasma GH, PRL and cortisol plasma basal values or in GH and PRL responses to GHRH between schizophrenics and controls was observed. Our failure to demonstrate a difference in GH response to GHRH between schizophrenics and controls would seem to indicate that GH secretory pituitary reserve is intact in young acute male schizophrenics. Cortisol values did discriminate between schizophrenics and controls (p less than 0.05). In our sample, both schizophrenics and normal controls showed a slight but significant (p less than 0.03) and transitory increase in plasma PRL response to GHRH.

Reduced natural killer cell activity in major depression: neuroendocrine implications

Natural killer cell activity (NKCA) was significantly reduced in a group of depressed patients, melancholic subtype, compared to sex- and age-matched controls. Corticotropin and cortisol values were significantly higher in the depressed subjects than in the controls, but no correlation between high hormone levels and low immunological activity was found in the patients.

Rapid and sensitive method for high-performance liquid chromatographic analysis of pterins in biological fluids

A rapid and sensitive high-performance liquid chromatographic (HPLC) method for the analysis of the most important urinary pterins is described. The method involves a preliminary sample oxidation to stabilize and convert pterins into their fluorescent forms and a purification by anion-exchange chromatography, followed by a short reversed-phase HPLC separation with fluorometric detection and quantitation of the different pterins. A complete HPLC analysis is accomplished in as little as 15 min. The sensitivity of the method allows the detection of as little as 20 pg of each pterin with a mean recovery greater than 99% for all pterins analysed. Reference values were obtained from 50 normal babies aged between 1 and 120 days. A significant correlation was found between urinary biopterin levels and the age of the babies (r = 0.445), while neopterin did not show any significant correlation with age. The "biopterin neopterin creatinine ratio" (BNCR index) was also significantly correlated with the age of the babies (r = 0.428). This rapid and sensitive method for pterin determination in biological fluids may be useful in the differential diagnosis of the various hyperphenylalaninemic conditions identified by neonatal mass screening programmes.

Corticotropin-releasing factor and adrenal function in major depression

We investigated ACTH and cortisol responses after ovine CRF injection (1 microgram/kg one bolus) in a group of 11 drug-free patients suffering from major depression. When compared to sex- and age-matched normal controls, our depressed patients showed: Higher ACTH basal values (p less than 0.002); higher cortisol basal values (p less than 0.009); blunted ACTH response to oCRF administration (p less than 0.23); higher cortisol response to oCRF (p less than 0.001). Our data show that in depressed patients the feed-back mechanism is functionally intact at the pituitary level on one hand, while on the other, a hyperresponsiveness of adrenal cortex (even to minimal stimuli) seems to be present. Moreover, a hypersecretion of endogenous CRF in these patients seems to be likely.

Plasma amino acid values and pancreatic beta-cell function in phenylketonuria

In 16 phenylketonuric (PKU) patients aged 5-12 years, plasma glucose, immunoreactive insulin (IRI), C-peptide (CP) and plasma amino acids were measured in basal conditions and under a standard oral glucose tolerance test (OGTT). The beta-cell response to OGTT was higher in PKU patients than in normal subjects as demonstrated by peak levels and areas under the curves of plasma concentrations of IRI and of CP. A significant correlation was observed between plasma phenylalanine values and both IRI and CP 'output' in PKU patients. Mean concentrations of branched chain amino acids and tyrosine in plasma decreased significantly during OGTT, while phenylalanine values increased in PKU subjects.

Incidence of classic PKU in Italy estimated from consanguineous marriages and from neonatal screening

As already described for cystic fibrosis and Friedreich ataxia, the incidence of PKU in Italy has been estimated by determining the increase of consanguineous marriages among 178 couples of PKU parents over the frequencies carefully established for the same marriages in the general Italian population for each of the 95 provinces during a 55-year period. The incidence estimated (between 1/15595 and 1/17815 according to two different formulas) is not very different from the incidence derived from screening programs (almost 1/12000). This indicates that the former method can be applied in Italy to the study of the incidence of other autosomal recessive disorders.

EEG as a possible prognostic tool in phenylketonuria

Clinical EEG and biochemical data were recorded in 10 children with classical PKU and 5 with variant forms of hyperphenylalaninaemias during the first year of life. A semiquantitative evaluation of the EEG showed a high correlation between epileptiform abnormalities and phenylalanine blood levels in the first 90 days of life and therefore with the delay before dietary therapy in PKU children. Although performed on a limited population, such an approach may indicate an additional non-computerized EEG tool for the clinical management of hyperphenylalaninaemias, and suggest some criteria for neurophysiological risk evaluation during the first year of life.

Multiple neonatal screening for aminoacidopathies by ion exchange chromatography

The experience gained in a pilot programme for multiple screening for amino acid disorders is reported. Over 222,000 newborn infants were screened by ion-exchange chromatography using dried blood spots. The acceptability, reliability and validity of the method are reported, and an outline is given, of the field evaluation of the method over 4 years, together with a short cost analysis. Incidences of the screened diseases and their differences from other reports are also discussed.

Neonatal screening in Italy for congenital hypothyroidism and metabolic disorders: hyperphenylalaninemia, maple syrup urine disease and homocystinuria

A multiple screening program to establish the frequency of congenital hypothyroidism (CH), phenylketonuria (PKU), maple syrup urine disease (MSUD), homocystinuria and hypertyrosinemia in endemic and sporadic goitrous regions of Italy is being carried out. Valine, methionine, leucine, isoleucine, tyrosine and phenylalanine, eluted from a single spot and separated by column chromatography, are measured, using whole blood adsorbed on filter paper. CH is detected by RIA assay of TSH eluted from dried blood spot. A cut-off of 100 microU/ml for TSH is used providing a recall rate of 0.38%. Out of 116,000 newborn infants screened for aminoacidopathies (since 1974), 16 PKU patients, 3 affected by MSUD, 2 homocystinuric babies have been detected. Out of 25,400 newborn infants screened for CH, 5 patients were affected by permanent CH and 29 by transient hyperthyrotropinemia. Thus PKU shows a frequency of 1:7,200 newborn infants, and permanent congenital hypothyroidism 1:5,080. The coordination of screening programs for congenital metabolic diseases in a single central unit allows:--the unification of the input of samples and output of data in a single data bank;--a minimization of the physical and psychological stress to the patients and their families;--and a more satisfactory cost/benefit ratio.

Immunoreactive trypsin on dried-blood spots as a possible neonatal test for cystic fibrosis. (I. Evaluation of the method and preliminary field trial)

A method for blood spot immunoreactive trypsin (IRT) determination suitable for neonatal mass screening, and the preliminary steps towards its large-scale application are described. The method showed a highly significant correlation between blood spot and plasma values, and a study of plasma reference values in a population of 1,050 newborn infants demonstrated a log-normal distribution with a mean IRT concentration of 238.3 ng/ml. The results and their implications for neonatal mass screening are discussed.

[Plasma levels of phenobarbital in epileptic children. Effect of combination with other anticonvulsants]

The effect of age on the steady state levels of phenobarbitone, alone and when given with phenytoin, sodium valproate and ethosuccimide has been measured in 1 361 children whose ages ranged from one month to 12 years. The relationship between dose and plasma level differed in those under 2 years from those aged between 2 years and 12 years. The addition of the other drugs altered the pharmacokinetics of phenobarbitone.