Clinical and biochemical phenotypes, genotypes, and long-term outcomes of individuals with galactosemia type I from a single metabolic genetics center in Alberta.

Background: Galactosemia type I is an autosomal recessive disorder of galactose metabolism due to galactose-1-phosphate uridyltransferase deficiency, encoded by GALT. To investigate the phenotypes, genotypes and long-term outcomes of galactosemia, we performed a retrospective cohort study in our center. Methods: All individuals with galactosemia type I were included. We divided individuals into two groups to compare the outcomes of those treated symptomatically (SymX) and asymptomatically (AsymX). We reviewed electronic patient charts for clinical features, biochemical investigations, molecular genetic investigations, treatments, and outcomes. Results: There were 25 individuals including classic (n = 17), clinical variant (n = 4), and biochemical variant (Duarte) galactosemia (n = 4). Twelve individuals were diagnosed symptomatically (SymX), and 9 individuals were diagnosed asymptomatically (AsymX). We did not include individuals with biochemical variant (Duarte) galactosemia into any of these groups. At the time of the diagnosis, conjugated hyperbilirubinemia was present in 83.3% of SymX group, whereas only 22% of AsymX group. SymX group had hepatomegaly (25%), failure to thrive (33.3%), cataract (16.7%) and sepsis (25%), whereas none of the individuals in the AsymX group had these clinical features. Fourteen variants in GALT were identified including pathogenic/likely pathogenic (n = 12), and likely benign/benign (n = 2) variants. The vast majority of individuals with classic and clinical variant galactosemia were treated with a galactose-lactose-free diet for life (n = 20/21). Intellectual disability was present in 54.5% of the SymX group, and in 37.5% of the AsymX group as a long-term outcome. Tremors were present 50% of the SymX group, and in 22% of the AsymX group as a long-term outcome. Although, intellectual disability and tremors seem to be less common in the AsymX group, there was no statistically significant difference between both groups. Primary ovarian insufficiency was present 50% of the SymX group, whereas in 20% of the AsymX group in post-pubertal females. We report a novel hypomorphic GALT variant (p.Ala303Ser) in one individual with clinical variant galactosemia. We also report an individual with clinical variant galactosemia with normal urine galactitol levels on a normal diet. Conclusion: It seems that newborn screening and early administration of a galactose-lactose-free diet decreases the long-term galactosemia-associated complications but does not prevent them completely. It may be that not all individuals with clinical variant galactosemia may need a galactose-lactose-free diet. It is timely to find new therapeutic strategies that can reduce the frequency of late-onset complications in galactosemia.

Outcomes of mitochondrial long chain fatty acid oxidation and carnitine defects from a single center metabolic genetics clinic.

BACKGROUND: Mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects are a group of inherited metabolic diseases. We performed a retrospective cohort study to report on the phenotypic and genotypic spectrum of mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects as well as their treatment outcomes. METHODS: All patients with mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects were included. We divided patients into two groups to compare outcomes of those treated symptomatically (SymX) and asymptomatically (AsymX). We reviewed patient charts for clinical features, biochemical investigations, molecular genetic investigations, cardiac assessments, neuroimaging, treatments, and outcomes. RESULTS: There were 38 patients including VLCAD (n = 5), LCHAD (n = 4), CACT (n = 3), MAD (n = 1), CPT-I (n = 13), CPT-II (n = 3) deficiencies and CTD (n = 9). Fourteen patients were diagnosed symptomatically (SymX), and 24 patients were diagnosed asymptomatically (AsymX). Twenty-eight variants in seven genes were identified in 36 patients (pathogenic/likely pathogenic n = 25; variant of unknown significance n = 3). Four of those variants were novel. All patients with LCHAD deficiency had the common variant (p.Glu474Gln) in HADHA and their phenotype was similar to the patients reported in the literature for this genotype. Only one patient with VLCAD deficiency had the common p.Val283Ala in ACADVL. The different genotypes in the SymX and AsymX groups for VLCAD deficiency presented with similar phenotypes. Eight patients were treated with carnitine supplementation [CTD (n = 6), CPT-II (n = 1), and MAD (n = 1) deficiencies]. Thirteen patients were treated with a long-chain fat restricted diet and MCT supplementation. A statistically significant association was found between rhabdomyolysis, and hypoglycemia in the SymX group compared to the AsymX group. A higher number of hospital admissions, longer duration of hospital admissions and higher CK levels were observed in the SymX group, even though the symptomatic group was only 37% of the study cohort. CONCLUSION: Seven different mitochondrial long-chain fatty acid oxidation and carnitine metabolism defects were present in our study cohort. In our clinic, the prevalence of mitochondrial long-chain fatty acid oxidation and carnitine defects was 4.75%.

Improved electroretinographic responses following dietary intervention in a patient with Refsum disease.

Refsum disease is a rare inherited metabolic disorder arising from a defect in peroxisomal metabolism. Patients lack the functional enzyme phytanoyl-CoA hydroxylase, resulting in perturbed alpha oxidation of fatty acids. Phytanic acid accumulates in nervous and adipose tissue and leads to several disease phenotypes including early-onset retinal degeneration, hearing loss, peripheral neuropathy, anosmia, and cerebellar ataxia, among others. Currently, restricting dietary phytanic acid is the only means of altering the chronic sequelae and the disease course. While dietary intervention has been demonstrated to improve peripheral neuropathy, ichthyosis, and ataxia, there have been no reports of improved retinal function in patients with Refsum disease. We describe the case of a 51-year-old patient with molecularly and biochemically confirmed Refsum disease who underwent electroretinography before and after beginning a phytanic acid-restricted diet. His post-intervention 30 Hz flicker electroretinogram demonstrated significantly improved waveform amplitudes and implicit times, suggesting improved retinal function. Thus, we propose that the possibility exists for some visual recovery in these patients and we highlight the utility of performing standardized electroretinography to assess treatment response in Refsum disease.

Hypertryptophanemia due to tryptophan 2,3-dioxygenase deficiency.

In this report we describe the first human case of hypertryptophanemia confirmed to be due to tryptophan 2,3-dioxygenase deficiency. The underlying etiology was established by sequencing the TDO2 gene, in which there was compound heterozygosity for two rare variants: c.324G>C, p.Met108Ile and c.491dup, p.Ile165Aspfs*12. The pathogenicity of these variants was confirmed by molecular-level studies, which showed that c.491dup does not produce soluble protein and c.324G>C results in a catalytically less efficient Met108Ile enzyme that is prone to proteolytic degradation. The biochemical phenotype of hypertryptophanemia and hyperserotoninemia does not appear to have significant clinical consequences.

A case of 8q22.1 microdeletion without the Nablus mask-like facial syndrome phenotype.

Nablus mask-like facial syndrome (NMLFS) has been reported in six patients with a recognizable facial appearance, along with other clinical features. Microdeletions of 8q21.3-8q22.1 were identified in all six cases, with the deleted region in common being 8q22.1 (2.78 Mb in length). In this report, we describe a child with speech delay and features of an autistic spectrum disorder and with a 1.6 Mb deletion of 8q22.1. The deletion has significant chromosomal overlap with previously reported examples of NMLFS, but our patient lacks the clinical features noted in the published cases.

High copper levels and increased elastolysis in a patient with cutis marmorata teleangiectasia congenita.

Cutis marmorata telangiectatica congenita (CMTC) is a rare cutaneous vascular disease presenting at birth with levido reticularis, phlebectasia, and telangiectasia, often accompanied by skin ulcerations. Extra-dermal vascular anomalies can be also detected in 30-70% of described cases. The pathomechanism responsible for development of these phenotypic changes is not well understood. Here, we report on a 16-month-old boy with CMTC, generalized vascular abnormalities and severe, nitric oxide sensitive, pulmonary hypertension associating with markedly elevated level of blood copper. Results of laboratory investigations indicated that primary cultures (passage one) of dermal fibroblasts derived from this patient were capable of normal synthesis of tropoelastin, but their net deposition of mature elastic fibers was significantly diminished as compared with cultures of normal fibroblasts. Because the low net deposition of elastin was reversed when 1 mg/ml of alpha1-antitrypsin was added to the media, we conclude that heightened elastolysis by endogenous serine proteinase's is responsible for the low net elastogenesis by CMTC fibroblasts. Since simultaneous addition of 30 microM CuSO(4) and 1 mg/ml alpha1-antitrypsin abolished the beneficial effect of this serine proteinase's inhibitor, we concluded that this may be due to copper-dependent inactivation of alpha1-antitrypsin. Our data suggest that a high level of free copper may constitute a major triggering factor contributing to the development of the CMTC phenotype.

Young children's perceptions of physicians wearing standard precautions versus customary attire.

OBJECTIVE: The aim of the study was to determine if young children have a preference regarding whether physicians wear standard precautions attire. METHODS: One hundred ninety-seven children, aged 4 to 8 years, and their parents were recruited from the pediatric emergency department of a tertiary care center. Two sets of 4 photographs-the same man in formal attire, a white coat, greens, and severe acute respiratory syndrome (SARS) standard precautions attire, and the same woman in formal attire, a white coat, greens, and SARS standard precautions attire-were shown to the children and their caregiver. Both were asked which physician's attire he or she liked the most and which he or she liked the least. Parents filled out a questionnaire regarding their experiences in the pediatric emergency department during the SARS epidemic. RESULTS: The children selected the physician in SARS standard precautions attire as most liked 17.5% of the time and least liked 53.3% of the time. The parents selected the physician in SARS standard precautions attire as most liked 0% of the time and least liked 94.8% of the time. CONCLUSIONS: Physicians wearing standard precautions attire while working in the pediatric emergency department need to be aware that this attire may negatively impact their relationship with pediatric patients 4 to 8 years of age.