M. Estela Rubio-Gozalbo

High phenylalanine levels directly affect mood and sustained attention in adults with phenylketonuria: a randomised, double-blind, placebo-controlled, crossover trial

The main debate in the treatment of Phenylketonuria (PKU) is whether adult patients need the strict phenylalanine (Phe)-restricted diet. Physicians and patients lack evidence-based guidelines to help them make well-informed choices. We have carried out the first randomised double-blind placebo-controlled trial into the effects of short-term elevation of Phe levels on neuropsychological functions and mood of adults with PKU. Nine continuously treated adults with PKU underwent two 4-week supplementation periods: one with Phe, mimicking normal dietary intake, and one with placebo in randomly allocated order via a randomisation coding list in a double-blind cross-over design. A set of neuropsychological tests (Amsterdam Neuropsychological Tasks) was administered at the end of each study period. In addition, patients and for each patient a friend or relative, completed weekly Profile of Mood States (POMS) questionnaires, evaluating the patients’ mood. Phe levels were measured twice weekly. Mean plasma Phe levels were significantly higher during Phe supplementation compared with placebo (p = 0.008). Neuropsychological tests demonstrated an impairment in sustained attention during Phe supplementation (p = 0.029). Both patients and their friend or relative reported lower scores on the POMS questionnaires during Phe supplementation (p = 0.017 and p = 0.040, respectively). High plasma Phe levels have a direct negative effect on both sustained attention and on mood in adult patients with PKU. A Phe-restricted “diet for life” might be an advisable option for many.

Fertility and impact of pregnancies on the mother and child in classic galactosemia

Despite the high prevalence of premature ovarian failure (POF) and subsequent infertility in galactosemic women, spontaneous pregnancies occur and may not be as rare as is generally assumed. This is important for counseling these women on fertility. The purpose of this review is to assess the occurrence and predicting factors of pregnancy, and to evaluate the impact of pregnancy on the mothers and childs health. The female Dutch galactosemia population (age > 18 years) was studied, and a literature search on articles reporting pregnancy in galactosemic women, published between January 1971 and December 2007, was performed. Twenty-two galactosemic women were studied. Nine women have tried to conceive, of which 4 were successful. Three mothers were diagnosed with POF before the first pregnancy and/or in between pregnancies. In literature, 50 pregnancy reports were found. In 10 pregnancy reports from the literature, the mothers genotype is known. Four women were homozygous for the Q188R mutation, which equals the incidence of 40–45% of classic galactosemia caused by this mutation. This study challenges the current opinion that the chance of becoming pregnant is small in classic galactosemia. Despite POF in most galactosemic women, pregnancies do occur. The genotype and GALT-activity do not seem to predict the chance of becoming pregnant, whereas the occurrence of spontaneous menarche might. No evidence for the need of additional check-ups during the pregnancy and puerperium was found. Elevations in galactose-metabolites do occur, but without evidence of clinical impact for the mother or the child, although possible long-term effects have not been thoroughly investigated. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to summarize the purported causes and sequelae of galactosemia, explain the possible sequelae of galactosemia, distinguish alterations of the ovary and the hypothalamic-pituitary axis, identify the frequency of pregnancy and the possible outcome of the offspring, and outline dietary management of patients with galactosemia.

FSH isoform pattern in classic galactosemia

Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns of five classic galactosemia patients with POI were compared to the pattern obtained in two patients with a primary glycosylation disorder (phosphomannomutase-2-deficient congenital disorders of glycosylation, PMM2-CDG) and POI, and in five postmenopausal women as controls. We used FPLC chromatofocussing with measurement of FSH concentration per fraction, and discovered that there were no significant differences between galactosemia patients, PMM2-CDG patients and postmenopausal controls. Our results do not support that FSH dysfunction due to a less acidic isoform pattern because of hypoglycosylation is a key mechanism of POI in this disease.

Pregnancy in classic galactosemia despite undetectable anti-Müllerian hormone

OBJECTIVE To report a pregnancy in a patient with classic galactosemia despite signs of no ovarian reserve to draw attention to the limited predictive value of ovarian reserve tests in these patients. DESIGN Case report. SETTING Secondary and tertiary care center. PATIENT(S) A patient with classic galactosemia with premature ovarian failure and two previous pregnancies. INTERVENTION(S) Exogenous FSH ovarian reserve test and anti-Müllerian hormone (AMH) measurement. MAIN OUTCOME MEASURE(S) 17beta-Estradiol response, AMH level. RESULT(S) Pregnancy despite undetectable AMH (<0.1 microg/L) and no E(2) response (exogenous FSH ovarian reserve test). CONCLUSION(S) Fluctuating premature ovarian failure makes fertility counseling of patients with classic galactosemia difficult. Commonly used ovarian function and reserve tests seem to have no significance.

Effect of calcium, vitamins K1 and D3 on bone in galactosemia

Classical galactosemia is an inherited disorder of galactose metabolism. Recently, diminished bone mineral content (BMC) in children and adolescents has been found. The aim of this study was to evaluate the effect of calcium, vitamins K(1) and D(3) supplementation on bone in children with galactosemia. A 2-year randomized, double-blind, placebo-controlled clinical trial was undertaken in which 40 children with classical galactosemia (13 males and 27 females, aged 3-17 years) were included to receive daily either 750 mg calcium, 1.0 mg vitamin K(1) and 10.0 microg vitamin D(3) or placebo. BMC of femoral neck, lumbar spine and total body and body composition data were determined by dual energy X-ray absorptiometry (DXA) at baseline and after 1 and 2 years. Diet was assessed using a food frequency questionnaire and a 3-day food diary. Biochemical measurements were determined at baseline and after 1 and 2 years. In the children receiving treatment, carboxylated osteocalcin (cOC) concentration significantly increased (P < 0.001) and undercarboxylated osteocalcin (ucOC) concentration significantly decreased (P = 0.001) when compared to the children receiving placebo. Furthermore, there was a statistically significant increase in BMC of lumbar spine (P = 0.001), lean tissue mass (LTM: P = 0.016) and fat mass (FM: P = 0.014) in the treatment group when compared to the placebo group. The significant increase in cOC and decrease in ucOC concentration in the treatment group were present in prepubertal (P < 0.001 and P = 0.006 respectively) and pubertal children (P = 0.004 and P = 0.042 respectively). The significant increase in BMC of lumbar spine in the treatment group was present only in the prepubertal children (P = 0.015). Supplementation of calcium, vitamins K(1) and D(3) given in this dose (750 mg, 1.0 mg and 10.0 mug respectively) is likely to have a role in the treatment of BMC abnormalities in galactosemia.

Classical galactosaemia: novel insights in IgG N -glycosylation and N -glycan biosynthesis

Classical galactosaemia (OMIM #230400), a rare disorder of carbohydrate metabolism, is caused by a deficient activity of galactose-1-phosphate uridyltransferase (EC 2.7.7.12). The pathophysiology of the long-term complications, mainly cognitive, neurological and female fertility problems remains poorly understood. The lack of validated biomarkers to determine prognosis, monitor disease progression and responses to new therapies, pose a huge challenge. We report the detailed analysis of an automated robotic hydrophilic interaction ultra-performance liquid chromatography N-glycan analytical method of high glycan peak resolution applied to serum IgG. This has revealed specific N-glycan processing defects observed in 40 adult galactosaemia patients (adults and adolescents), in comparison with 81 matched healthy controls. We have identified a significant increase in core fucosylated neutral glycans (P<0.0001) and a significant decrease in core fucosylated (P<0.001), non-fucosylated (P<0.0001) bisected glycans and, of specific note, decreased N-linked mannose-5 glycans (P<0.0001), in galactosaemia patients. We also report the abnormal expression of a number of related relevant N-glycan biosynthesis genes in peripheral blood mononuclear cells from 32 adult galactosaemia patients. We have noted significant dysregulation of two key N-glycan biosynthesis genes: ALG9 upregulated (P<0.001) and MGAT1 downregulated (P<0.01) in galactosaemia patients, which may contribute to its ongoing pathophysiology. Our data suggest that the use of IgG N-glycosylation analysis with matched N-glycan biosynthesis gene profiles may provide useful biomarkers for monitoring response to therapy and interventions. They also indicate potential gene modifying steps in this N-glycan biosynthesis pathway, of relevance to galactosaemia and related N-glycan biosynthesis disorders.

Fertility preservation in female classic galactosemia patients.

Almost every female classic galactosemia patient develops primary ovarian insufficiency (POI) as a diet-independent complication of the disease. This is a major concern for patients and their parents, and physicians are often asked about possible options to preserve fertility. Unfortunately, there are no recommendations on fertility preservation in this group. The unique pathophysiology of classic galactosemia with a severely reduced follicle pool at an early age requires an adjusted approach. In this article recommendations for physicians based on current knowledge concerning galactosemia and fertility preservation are made. Fertility preservation is only likely to be successful in very young prepubertal patients. In this group, cryopreservation of ovarian tissue is currently the only available technique. However, this technique is not ready for clinical application, it is considered experimental and reduces the ovarian reserve. Fertility preservation at an early age also raises ethical questions that should be taken into account. In addition, spontaneous conception despite POI is well described in classic galactosemia. The uncertainty surrounding fertility preservation and the significant chance of spontaneous pregnancy warrant counseling towards conservative application of these techniques. We propose that fertility preservation should only be offered with appropriate institutional research ethics approval to classic galactosemia girls at a young prepubertal age.

Galactose metabolism and health.

Purpose of reviewGalactose – a key source of energy and a crucial structural element in complex molecules – is particularly important for early human development. However, galactose metabolism might be important not only for fetal and neonatal development but also for adulthood, as evidenced by the inherited disorders of galactose metabolism. The purpose of this review is to summarize the current evidence of galactose metabolism in health and disease. Recent findingsThe biological importance of galactose goes beyond its importance as a nutrient and a metabolite. Galactose has been selected by evolutionary pressure to exert also a crucial structural role in macromolecules. Additionally, galactose has recently been reported as beneficial in a number of diseases, particularly in those affecting the brain. SummaryGalactose is crucial for human metabolism, with an established role in energy delivery and galactosylation of complex molecules, and evidence for other roles is emerging.

Risk stratification by residual enzyme activity after newborn screening for medium-chain acyl-CoA dehyrogenase deficiency: data from a cohort study

BackgroundSince the introduction of medium-chain acyl coenzyme A dehydrogenase (MCAD) deficiency in population newborn bloodspot screening (NBS) programs, subjects have been identified with variant ACADM (gene encoding MCAD enzyme) genotypes that have never been identified in clinically ascertained patients. It could be hypothesised that residual MCAD enzyme activity can contribute in risk stratification of subjects with variant ACADM genotypes.MethodsWe performed a retrospective cohort study of all patients identified upon population NBS for MCAD deficiency in the Netherlands between 2007–2010. Clinical, molecular, and enzymatic data were integrated.ResultsEighty-four patients from 76 families were identified. Twenty-two percent of the subjects had a variant ACADM genotype. In patients with classical ACADM genotypes, residual MCAD enzyme activity was significantly lower (median 0%, range 0-8%) when compared to subjects with variant ACADM genotypes (range 0-63%; 4 cases with 0%, remainder 20-63%). Patients with (fatal) neonatal presentations before diagnosis displayed residual MCAD enzyme activities <1%. After diagnosis and initiation of treatment, residual MCAD enzyme activities <10% were associated with an increased risk of hypoglycaemia and carnitine supplementation. The prevalence of MCAD deficiency upon screening was 1/8,750 (95% CI 1/7,210–1/11,130).ConclusionsDetermination of residual MCAD enzyme activity improves our understanding of variant ACADM genotypes and may contribute to risk stratification. Subjects with variant ACADM genotypes and residual MCAD enzyme activities <10% should be considered to have the same risks as patients with classical ACADM genotypes. Parental instructions and an emergency regimen will remain principles of the treatment in any type of MCAD deficiency, as the effect of intercurrent illness on residual MCAD enzyme activity remains uncertain. There are, however, arguments in favour of abandoning the general advice to avoid prolonged fasting in subjects with variant ACADM genotypes and >10% residual MCAD enzyme activity.

Evaluation of quality of life in PKU before and after introducing tetrahydrobiopterin (BH4): A prospective multi-center cohort study

BACKGROUND Phenylketonuria (PKU) is a rare inborn error of metabolism caused by phenylalanine hydroxylase enzyme (PAH) deficiency. Treatment constitutes a strict Phe restricted diet with unpalatable amino acid supplements. Residual PAH activity enhancement with its cofactor tetrahydrobiopterin (BH4) is a novel treatment which increases dietary tolerance in some patients and permits dietary relaxation. Relaxation of diet may improve health related quality of life (HRQoL). This prospective cohort study aims to evaluate HRQoL of patients with PKU and effects of BH4 treatment on HRQoL. METHODS Patients aged 4years and older, diagnosed through newborn screening and early and continuously treated, were recruited from eight metabolic centers. Patients and mothers completed validated generic and chronic health-conditions HRQoL questionnaires (PedsQL, TAAQOL, and DISABKIDS) twice: before and after testing BH4 responsivity. Baseline results were compared to the general population. Data collected after BH4 testing was used to find differences in HRQoL between BH4 unresponsive patients and BH4 responsive patients after one year of treatment with BH4. Also a within patient comparison was performed to find differences in HRQoL before and after treatment with BH4. RESULTS 69/81 (85%) patients completed the questionnaires before BH4 responsivity testing, and 45/69 (65%) participated again after testing. Overall PKU patients demonstrated normal HRQoL. However, some significant differences were found when compared to the general population. A significantly higher (thus better) score on the PedsQL was reported by children 8-12 years on physical functioning and by children 13-17 years on total and psychosocial functioning. Furthermore, adult patients reported significantly lower (thus worse) scores in the TAAQOL cognitive domain. 10 patients proved to be responsive to BH4 treatment; however improvement in their HRQoL after relaxation of diet could not be demonstrated.