Partial biotinidase deficiency associated with Coffin-Siris syndrome

Coffin-Siris syndrome is an infrequent condition characterised by mental retardation, nail hypoplasia or absence with fifth digit involvement and feeding problems. In addition, sparse scalp hair and chronic intractable eczema has been described in this syndrome. We report a 26-month-old girl with the disease and partial biotinidase deficiency.     

Hemophagocytic syndrome in a 4-month-old infant with biotinidase deficiency

Hemophagocytic syndromes such as hemophagocytic lymphohistiocytosis (HLH) are life-threatening hyperinflammatory conditions caused by inherited or acquired immune disorders. Awareness of the clinical symptoms and diagnostic criteria for hemophagocytic syndromes is crucial to start timely life-saving therapy. We present a case of a 4-month-old boy presenting with HLH. However, the patient was subsequently diagnosed with biotinidase deficiency and was successfully treated with biotin-replacement therapy, upon which the hemophagocytic syndrome ceased. Subsequent laboratory evaluations revealed normal lymphocyte cytotoxicity and no mutations in genes associated with familial HLH were found. Biotinidase deficiency should be considered as a differential diagnosis of patients fulfilling HLH criteria.     

Low biotinidase activity in plasma of some preterm infants: possible source of false-positive screening results

Screening for biotinidase deficiency has been added recently to some national screening programmes. To clarify the problem of false-positive screening tests in premature infants, we have studied biotinidase activities in the plasma of this population in more detail. In 64 newborns (premature and term babies) biotinidase activities correlated positively with gestational age from the 2nd to the 30th day of life. During the 1st–3rd day the activities were below the normal adult range in all 64 infants. In 56 infants the activities subsequently increased gradually and reached the normal adult range during the 4th–40th day of life. In contrast, the biotinidase activities in eight preterm infants dropped during the 3rd–7th day of life. Impaired liver function as a possible cause for this finding could be ruled out in these infants. The lowest activities in these infants were measured during the 4th–6th day of life, i.e. unfortunately at a time when samples for the screening are normally taken. According to our data, 4–8 out of 48 preterm or small-for-date infants with biotinidase activities ranging from 4.7%–26% of the mean adult value would have given false-positive screening tests. A positive screening test was also obtained in a newborn and in an older unrelated child with a partial biotinidase deficiency. In these children the biotinidase activity did not rise but remained slightly below or at the lower range for heterozygotes (at 31% and 38% of the mean adult value). Currently we do not know whether such individuals are heterozygotes, or whether they have a variant of biotinidase deficiency. However, these children have developed normally without biotin therapy.Abbreviations DTT dithiothreitol     

The effect of neonatal jaundice on biotinidase activity

BACKGROUND: Jaundice is one of the most common and one of the vexing problems that can occur in newborns. A newborn screening test for biotinidase deficiency has been added to many national screening programmes. AIM: To clarify the problem of false-positive screening tests in neonates, especially in term babies, we evaluated the biotinidase activity in the serum of fullterm, premature and small-for-dates newborn infants with jaundice. METHODS: 1296 fullterms (controls N=426), 246 prematures (controls N=86) and 156 small-for-dates babies (controls N=38) aged 2-3 days with jaundice were included in the study. In jaundiced neonates and controls, 3.0 ml of blood was drawn for the evaluation of total bilirubin (t.bil), liver enzymes and biotinidase activity in the serum using a fluorimetric method. In order to test whether or not t.bil causes an artifact in the previous method, biotinidase activity was also evaluated in a number of jaundiced newborns using an HPLC method. Additionally, a preliminary in vitro experiment was carried out to test whether t.bil is an inhibitor of the enzyme. RESULTS: Biotinidase activities in the group of controls of prematures (3.30+/-1.2 mmol/min/l) and small-for-dates babies (3.34+/-0.8 mmol/min/l) were lower than those of term babies (4.99+/-1.1 mmol/min/l, p<0.001). T.bil and liver enzymes showed a statistically significant inverse correlation with biotinidase activity (p<0.001) in all the jaundiced infants of this study. Additionally, biotinidase activity, evaluated in a number of neonates with both fluorimetric and HPLC methods showed similar results. Preincubation of the serum enzyme with t.bil (>10 mg/dl) resulted in a 50% or more inhibition. CONCLUSIONS: (a) Low biotinidase activity was found in term babies, prematures and small-for-dates with jaundice. (b) The low activity of the enzyme could be due to their impaired liver function. (c) The high t.bil levels in the studied groups may play the role of an "inhibitor" of the enzyme. (d) Gestational age as well as t.bil levels should always be written on Guthrie cards for a correct evaluation of biotinidase activity.     

Serum biotinidase activity in children with chronic liver disease and its clinical significance.

BACKGROUND: Biotinidase is the enzyme responsible for liberating the vitamin biotin from biocytin and dietary protein-bound vitamin. Individuals lacking biotinidase activity become biotin deficient. Because the liver is the major source of plasma biotinidase, chronic liver diseases can lead to decreased serum biotinidase activity and biotin deficiency. The aim of this study is to determine serum biotinidase activity values in children with chronic liver disease and to investigate the relation among enzyme activity, certain liver function tests, and degree of liver damage. METHOD: In this study, using a spectrophotometric method, biotinidase activity was determined in sera from 62 children with chronic liver diseases (median age, 9.73 years; range, 8 months to 18 years) and from 27 healthy controls. Diagnoses of the patient group were as follows: noncirrhotic chronic hepatitis B virus infection (n = 12), metabolic liver diseases (n = 16), autoimmune hepatitis (n = 6), intrahepatic and extrahepatic cholestasis (n = 14), fulminant hepatitis (n = 5), cryptogenic cirrhosis n = 5), prehepatic portal hypertension (n = 4). Meanwhile, serum albumin, total bilirubin, alkaline phosphatase, alanine aminotransferase, and gamma-glutamyltransferase concentrations and prothrombine time were determined for each patient and the results were correlated with serum biotinidase activity. RESULTS: There was significant difference between mean enzyme activity of the controls (7.6 +/- 1.2 nmol x min(-1) x mL(-1)) and of all patients with chronic liver disease (6.3 +/- 2.5 nmol x min(-1) x mL(-1)) ( P < 0.05). Serum biotinidase activity in patients with noncirrhotic chronic liver diseases (chronic viral hepatitis, prehepatic portal hypertension, glycogen storage disease, Gaucher disease) was within the normal ranges. However, serum biotinidase activity in patients with cirrhosis and Wilson disease was significantly less than that of the control group ( P < 0.05). The lowest enzyme activities were detected in patients with fulminant hepatitis. CONCLUSION: In this study, serum biotinidase activity was significantly lower in patients with cirrhosis, particularly in the patients with decompensated cirrhosis and fulminant hepatitis who exhibited no clinical symptoms related to biotin deficiency. The decreased serum biotinidase activity in chronic liver diseases was associated with severe impairment of hepatocellular function.     

Systemic hypertension and plasma renin activity in children with the hemolytic-uremic syndrome

A group of 21 children with HUS underwent serial estimations of PRA and blood pressure. At time of administration PRA was 13.2 divided by 1.59 ng/ml/hr (mean + SE), in seven who were hypertensive the mean was 14.1 +/- 3.2 ng/ml/hr and despite the wide range PRA was considered to be elevated in 6 of this group. The 14 normotensive children had a mean PRA of 12.8 +/- 1.8 ng/ml/hr, only 1 patient having a value within the normal range. In 9 children PRA was normal once diuresis had been established (9 +/- 1.4 ng/ml/hr) and only two patients of this group were hypertensive at time of the study. PRA measured in 8 children 4 weeks after presentation was 7 +/- 1.6 ng/ml/hr, and 3 hypertensive children having a mean value of 7.5 ng/ml/hr and the 5 normotensive children a mean of 2.5 ng/ml/hr. The data indicate that activation of the renin-angiotensin system in HUS occurs irrespective of hypertension. Furthermore blood pressure levels were not correlated to the degree of hydration.     

Bartter syndrome. Typical facies and normal plasma volume.

Two girls with hypokalemic and hypochloremic metabolic alkalosis and failure to thrive were found to have Bartter syndrome at ages 9 and 6 months. Both had normal blood pressures despite substantial elevation of plasma renin activity and evidence of secondary hyperaldosteronism. A similarity in facial features, including prominent forhead, a large head, triangular facies with drooping mouth, and large eyes and pinnae, was noted in these two infants and in published pictures of other infants with the syndrome. Although the normotension associated with substanital elevation of plasma renin activity and hyperaldosteronism in Bartter syndrome has been considered the effect of hypovolemia, a normal or slightly elevated plasma volume was found in these infants, suggesting that in certain cases an alternate mechanism for the depressed response to renin may be present.     

Maternal chronic hepatitis B virus does not affect neonatal biotinidase activity

BACKGROUND: Biotinidase activity is closely related to liver function. AIM: To evaluate whether maternal chronic hepatitis B virus (HBV) infection affects neonatal biotinidase activity. PATIENTS AND METHODS: Twenty-three asymptomatic pregnant women with HBV (group A) and 28 healthy pregnant women (controls) in the delivery room and their newborns (cord blood) underwent laboratory examinations. Serological HBV and liver function tests were performed with standard techniques, while biotinidase activity was measured with an HPLC method. RESULTS: Serological HBV tests and HBV DNA showed chronic HBV (precore mutant G1896A) in group A, whereas anti-HBc and anti-HBe were detected in their neonates. Liver function chemistry was found normal in controls and both groups of newborns. Moderately increased transaminases were found in the infected mothers. Interestingly, albumin levels did not differ among the studied groups. Biotinidase activity in HBV mothers (5.76+/-0.6 nmol/min/mL) was significantly decreased (p<0.001) as compared to controls (8.43+/-0.65 nmol/min/mL). The enzyme activity did not differ among the neonates. Biotinidase activity inversely correlated with transaminases but not with albumin or with HBV-DNA levels. CONCLUSIONS: Decreased biotinidase activities were evaluated in mothers with HBV and normal in their neonates. Biotin supplementation in the diseased mothers may prevent possible symptoms due to biotin recycling impairment.     

生物素与生物素酶缺乏症

生物素(biotin)又称为维生素B8、维生素H,是一种水溶性的含硫维生素,和其他B族维生素一样,大部分从食物中摄取,少数在机体肠道中的细菌体内合成。生物素广泛存在于天然食物中,以动物肝脏、大豆、蛋黄、鲜奶和酵母中含量较高,粮食、蔬菜、水果、肉类中含量很少。但是,食物中的生物素为蛋白结合状态,需在肠道中经过生物素酶的作用生成游离的生物素才能发挥作用[1～3]。1生物素的生理功能和代谢生物素是线粒体丙酰辅酶A羧化酶、丙酮酰羧化酶、乙酰辅酶A羧化酶和甲基巴豆酰辅酶A羧化酶的辅酶,作为羧化、脱羧和脱氢反应酶系的辅助因子参与碳水…     

Absence of plasma prostacyclin stimulating activity deficiency in hemolytic uremic syndrome

We compared the effect of plasma from 19 children with hemolytic uremic syndrome (HUS) on prostacyclin (PGI2) production by fresh rat aortic rings to the effect of plasma from 17 age- and sex-matched normal children, taking into account the PGI2 baseline aortic production (PGI2 release in presence of buffer, 21 determinations). After 10, 20, 30, 40, and 60 minutes incubation of rat aortic tissue with either plasma or buffer, the presence of PGI2 was studied by measuring by radioimmunoassay (RIA) the concentration of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). 6-keto-PGF1 alpha production increased with time in the two groups of plasma samples and in the presence of buffer, but 6-keto-PGF1 alpha production (ng/mg dried tissue) after 30 minutes incubation and mean 6-keto-PGF1 alpha production (slope of regression line, ng/mg/min) were significantly (P less than 0.01) lower in the presence of normal plasma compared with buffer, and significantly (P less than 0.01) higher in the presence of HUS plasma compared with normal plasma. There was no significant difference between buffer and HUS plasma. We conclude that, under our experimental conditions, normal plasma had an inhibitory activity on 6-keto-PGF1 alpha production by rat aorta. This inhibitory activity was absent in HUS plasma.     

Familial hemolytic-uremic syndrome with normal renal biopsy]

Five children from 3 different families, presented several attacks of hemolytic-uremic syndrome with peculiar features:--in 4/5 children the disease was familial; 4 presented 2 attacks, the 5th 3 attacks, separated by several months or years of time-interval;--the "bouts" were constantly marked by the initial high level of reticulocytes, rapid recovery of hematuria, renal failure and thrombocytopenia;--overall, repeated biopsies of the kidney never showed any lesion of the basement membrane of the glomerular capillaries or of the arteriolar walls leading to the diagnosis of thrombotic microangiopathy;--all etiological enquiries to precise the cause of chronic hemolysis were negative.     

The influence of valproic acid treatment on hair and serum zinc levels and serum biotinidase activity

Some of the side effects that develop during long-term valproic acid (VPA) treatment are similar to symptoms of zinc and partial biotinidase deficiencies. This situation suggests an association between these side effects and biotinidase and/or zinc deficiencies. In 32 pediatric patients (22 females, 10 males) receiving VPA treatment, hair and serum zinc levels and serum biotinidase activity (BA) were measured prior to and in the 3rd and 6th months of treatment. Also, serum VPA levels were measured in the 3rd and 6th months of treatment. The mean serum and hair zinc levels were found to be reduced in the 3rd and 6th months of treatment as compared with the pre-treatment values, while the mean serum BA was lower than the pre-treatment values in the 3rd month of treatment, but returned to initial values in the 6th month of treatment. In the 3rd and 6th months of treatment, patients complaining about hair loss had lower hair and serum zinc levels and serum BA but greater mean serum VPA than those who did not. However, the differences between parameters were not statistically significant. Our findings suggest that hair loss in patients can be attributed to zinc and BA depletion within the first 3 months, and to zinc depletion only by the 6th month.