PIGA Mutations Can Mimic Neonatal Hemochromatosis

GALD: new diagnostic tip for early diagnosis - a case report and literature review

Objective

Gestational alloimmune liver disease is a rare and serious condition caused by a maternal-fetal alloimmune disorder. There are not many studies about the antenatal treatment (IVIG infusion) of affected fetuses as the diagnosis is generally made postnatally. The possibility of an early diagnosis by means of ultrasonography and a gynecologist's assesment can provide prompt treatment of this disease.

Case report

We report the case of 38-year-old pregnant woman referred to our centre in view of severe fetal hydrops seen by ultrasound at 31 weeks + 1 day gestation. A male infant was born and subsequently died after developing liver failure. Postmortem examination revealed the presence of diffuse hepatic fibrosis in the absence of hemosiderin deposits and no extrahepatic siderosis. Immunohistochemical analysis was also performed which showed diffuse hepatocyte positivity for the terminal complement complex (C5b-C9) confirming the suspicion of GALD.

Methods

A comprehensive literature search published from 2000 to 2022 was conducted on PubMed and Scopus. Paper selection was performed following the PRISMA guidelines. Fifteen retrospective studies were identified and selected.

Results

A total of 15 manuscripts describing 26 cases were finally included in our research. Twenty-two fetuses/newborns with suspected GALD were studied, of which 11 had a confirmed histopathological diagnosis of GALD. Prenatal diagnosis of gestational alloimmune liver disease is difficult because ultrasound findings may be absent or nonspecific. Only one case report described fetal hydrops similar to our clinical case. As highlighted by the current case, in fetuses presenting with hydrops, once the most common etiologies have been excluded, hepatobiliary complications and liver failure caused by GALD should be considered.

Conclusions

Global knowledge of this disorder and its wide spectrum of presentations may help to increase the number of cases that are diagnosed early and accurately. The recurrence rate of an infant being affected with GALD in another pregnancy is more that 90%. Recurrence however can be prevented by treatment with IVIG during pregnancy. This highlights the importance of having obstetricians and pediatricians familiar with gestational alloimmune liver disease.

Neonatal Hemochromatosis: Systematic Review of Prenatal Ultrasound Findings—Is There a Place for MRI in the Diagnostic Process?

Neonatal hemochromatosis (NH) is an uncommon, severe disorder that results in fetal loss or neonatal death due to liver failure. NH is currently regarded as the phenotypic expression of gestational alloimmune liver disease (GALD). The diagnosis of NH-GALD is rarely prenatally established. In addition to providing a systematic review of the prenatal features that are identifiable using ultrasound (US) and MRI, we suggest a prenatal diagnosis algorithm for use in suspected NH during the first affected pregnancy. From a total of 586 database entries identified in PubMed, Google Scholar, and ResearchGate, we selected 18 studies published from 1993 to 2021 that reported maternal medical and obstetric history, prenatal ultrasound findings, and postpartum outcomes. We investigated the ultrasound and MRI features of these studies, along with the outcome due to this condition. A total of 74 cases were identified. The main reported prenatal US finding was fetal growth restriction (FGR) (33%), followed by oligohydramnios (13%) and hydrops fetalis (13%), with 13% cases described as uneventful. Other rare prenatal findings were fetal anemia, ascites, and abnormal fetal liver and spleen. Most pregnancies ended with fetal/perinatal death or therapeutic interruption of pregnancy. Favorable evolution with treatment (ensanguine transfusion and intravenous immunoglobulin (IVIG)) was reported for only 7% of fetuses. Using T2-weighted MRI, fetal extrahepatic siderosis confirmed prenatally in two cases and postnatally in 11 cases. IVIG treatment throughout subsequent pregnancies was found to significantly improve fetal prognosis. MRI should be indicated in selected cases of oligohydramnios, fetal hydrops, fetal hepatomegaly, ascites, or unexplained FGR or anemia after ruling out all other more frequently encountered conditions. MRI can be used to detect iron overload in the liver and extrahepatic siderosis.

New Players in Neuronal Iron Homeostasis: Insights from CRISPRi Studies

Selective regional iron accumulation is a hallmark of several neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. The underlying mechanisms of neuronal iron dyshomeostasis have been studied, mainly in a gene-by-gene approach. However, recent high-content phenotypic screens using CRISPR/Cas9-based gene perturbations allow for the identification of new pathways that contribute to iron accumulation in neuronal cells. Herein, we perform a bioinformatic analysis of a CRISPR-based screening of lysosomal iron accumulation and the functional genomics of human neurons derived from induced pluripotent stem cells (iPSCs). Consistent with previous studies, we identified mitochondrial electron transport chain dysfunction as one of the main mechanisms triggering iron accumulation, although we substantially expanded the gene set causing this phenomenon, encompassing mitochondrial complexes I to IV, several associated assembly factors, and coenzyme Q biosynthetic enzymes. Similarly, the loss of numerous genes participating through the complete macroautophagic process elicit iron accumulation. As a novelty, we found that the impaired synthesis of glycophosphatidylinositol (GPI) and GPI-anchored protein trafficking also trigger iron accumulation in a cell-autonomous manner. Finally, the loss of critical components of the iron transporters trafficking machinery, including MON2 and PD-associated gene VPS35, also contribute to increased neuronal levels. Our analysis suggests that neuronal iron accumulation can arise from the dysfunction of an expanded, previously uncharacterized array of molecular pathways.