RESUMEN
Creatine transporter deficiency has been described with normal or uninformative levels of creatine and creatinine in plasma, while urine has been the preferred specimen type for biochemical diagnosis. We report a cohort of untreated patients with creatine transporter deficiency and abnormal plasma creatine panel results, characterized mainly by markedly decreased plasma creatinine. We conclude that plasma should be considered a viable specimen type for the biochemical diagnosis of this disorder, and abnormal results should be followed up with further confirmatory testing.
Asunto(s)
Encefalopatías Metabólicas Innatas , Creatina , Creatina/deficiencia , Creatinina , Discapacidad Intelectual Ligada al Cromosoma X , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/deficiencia , Humanos , Creatina/sangre , Creatina/orina , Creatinina/sangre , Creatinina/orina , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/genética , Proteínas de Transporte de Neurotransmisores en la Membrana Plasmática/sangre , Masculino , Femenino , Discapacidad Intelectual Ligada al Cromosoma X/genética , Discapacidad Intelectual Ligada al Cromosoma X/sangre , Discapacidad Intelectual Ligada al Cromosoma X/diagnóstico , Niño , Preescolar , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/sangre , Proteínas del Tejido Nervioso/deficiencia , Lactante , Adolescente , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/deficiencia , Proteínas de Transporte de Membrana/sangre , AdultoRESUMEN
AIM: For people with haemophilia A (PwHA), bleeding in the joints leads to joint damage and haemophilia-related arthropathy, impacting range of motion and life expectancy. Existing guidelines for managing haemophilia A support healthcare professionals (HCPs) and PwHA in their efforts to preserve joint health. However, such guidance should be reviewed, considering emerging evidence and consensus as presented in this manuscript. METHODS: Fifteen HCPs experienced in the management of PwHA in the UK participated in a three-round Delphi panel. Consensus was defined at ≥70% of panellists agreeing or disagreeing for Likert-scale questions, and ≥70% selecting the same option for multiple- or single-choice questions. Questions not reaching consensus were revised for the next round. RESULTS: 26.8% (11/41), 44.8% (13/29) and 93.3% (14/15) of statements reached consensus in Rounds 1, 2 and 3, respectively. HCPs agreed that prophylaxis should be offered to patients with a baseline factor VIII (FVIII) level of ≤5 IU/dL and that, where there is no treatment burden, the aim of prophylaxis should be to achieve a trough FVIII level ≥15 IU/dL and maintain a longer period with FVIII levels of ≥20-30 IU/dL to provide better bleed protection. The aspirational goal for PwHA is to prevent all joint bleeds, which may be achieved by maintaining normalised (50-150 IU/dL) FVIII levels. CONCLUSION: The panel of experts were largely aligned on approaches to preserving joint health in PwHA, and this consensus may help guide HCPs.
Asunto(s)
Hemofilia A , Humanos , Hemofilia A/tratamiento farmacológico , Factor VIII/uso terapéutico , Consenso , Hemartrosis/prevención & control , Hemorragia/prevención & control , Reino UnidoRESUMEN
Treatment of phenylketonuria (PKU) has evolved since the initial introduction of a phenylalanine (Phe) restricted diet. The most recent option for adults affected with PKU is treatment with an alternate enzyme, phenylalanine ammonia lyase (PAL), that metabolizes excess Phe. Proper management of all patients with PKU relies on accurate measurement of Phe levels in blood, to comply with guidance intended to minimize the neurological symptoms. Recently, our laboratory was notified of discrepant results for a patient with PKU who is treated with pegvaliase. Two specimens were collected at the same time but yielded unexpectedly different Phe concentrations. After exclusion of specimen mix-ups or analytical errors, we suspected that there was residual pegvaliase activity in the specimens continuing to degrade Phe after collection. To investigate this possibility, we performed spiking studies that showed the degradation of Phe over time at ambient temperatures. Sample preparation by protein crash appears to deactivate pegvaliase and prevents further Phe degradation. However, because pegvaliase deactivation would be required immediately following blood collection, appropriate mitigation measures must be implemented, including stringent pre-analytical requirements, alternate sample matrices such as dried blood spots, or point of care testing. Until then, health care professionals need to be cautious in their interpretation of Phe levels in their patients with PKU that are treated with pegvaliase.