Lysosomal Storage Disorders in Nonimmune Hydrops Fetalis (NIHF): An Indian Experience

Prenatal diagnosis of mucopolysaccharidosis type I on hepatosplenomegaly and coarse features: a case-report

BACKGROUND

Mucopolysaccharidosis type I (MPS I - IDUA gene) is a rare autosomal recessive lysosomal storage disorder. Clinical symptoms, including visceral overload, are progressive and typically begin postnatally. Descriptions of hepatosplenomegaly associated with lysosomal pathology are uncommon during the prenatal period. The most prevalent etiologies are infections, anemia, and neoplasms.

CASE PRESENTATION

A pregnant woman at 26.5 gestational weeks was referred to our center for fetal ultrasound findings of hepatosplenomegaly, distinct facial features, and liver, spleen and thymus echogenic spots. Whole exome sequencing after amniocentesis identified two likely pathogenic IDUA gene variants (in trans), raising suspicion of a diagnosis of MPS I. MPS I was confirmed by the deficiency of α-L-iduronidase activity in amniotic cells. A medical pregnancy termination was carried out due to the severe prognosis. After termination of pregnancy, external examination of the fetus confirmed hepatosplenomegaly and coarse dysmorphic features.

CONCLUSION

Lysosomal storage diseases (LSD) are a rare cause of prenatal hepatosplenomegaly, but this has not been described in MPS I according to our literature search. The genetic variants identified in this case prompted early diagnosis through genome-wide studies. This rare presentation of MPS I highlights the expanding role of genomic analyses in diagnosing conditions during pregnancy.

Nonimmune Hydrops Fetalis

Nonimmune hydrops fetalis (NIHF) poses a significant challenge in perinatal care due to its high mortality rates and diverse etiologies. This comprehensive review examines the pathophysiology, etiology, antenatal diagnosis and management, postnatal care, and outcomes of NIHF. NIHF arises from numerous underlying pathologies, including genetic disorders, cardiovascular causes, and fetal infections, with advances in diagnostic techniques improving identification rates. Management strategies include termination of pregnancy for severe cases and fetal therapy for selected treatable etiologies, and neonatal care involves assessing and treating fluid collections and identifying underlying causes. Prognosis depends on factors such as gestational age at diagnosis and the extent of resuscitation needed, with challenges remaining in improving outcomes for affected infants.

Etiology and perinatal outcomes between early and late-onset nonimmune hydrops fetalis

OBJECTIVE

We aimed to compare the etiology and perinatal outcomes of non-immune hydrops fetalis diagnosed early- and late-onset at our hospital.

METHODS

The records of the patients who applied to our department were reviewed, and we reached 42 non-immune hydrops fetalis cases retrospectively and examined the medical records. Hydrops diagnosis week, birth week, accompanying anomalies, and perinatal outcomes were compared as ≤12 weeks (early-onset) and >12 weeks (late-onset).

RESULTS

The prevalence of non-immune hydrops fetalis was 0.05%, and the median week of diagnosis for hydrops was 18 weeks. Consanguinity (16.7%) was found in seven pregnancies, and the other seven patients (16.7%) had a history of hydrops in previous pregnancies. Anomalies of the skeletal system, central nervous system, and gastrointestinal tract accounted for 66.7% of ≤12 weeks in non-immune hydrops fetalis cases. Cardiac abnormalities were more common (26.7%) in patients at > 12 weeks (p=0.078). A statistically significant difference was found between the distribution of week of birth and week of diagnosis (p=0.029). Notably, 66.7% of patients diagnosed before week 12 and 23.3% of patients diagnosed after week 12 delivered their babies before week 24. Spontaneous intrauterine death occurred before week 12 in 45.5% (n=5) of non-immune hydrops fetalis and after week 12 in 39.1% (n=9) of non-immune hydrops fetalis. Notably, 69.2% (n=9) of the patients who had prenatal invasive testing resulted in normal karyotype.

CONCLUSION

In this study, most of the fetuses diagnosed with early-onset non-immune hydrops fetalis were born in the first 24 weeks. Additionally, live birth rates and cardiac anomalies were observed to be higher in late-onset non-immune hydrops fetalis.

Outcome and etiology of fetal pleural effusion, fetal ascites and hydrops fetalis after fetal intervention: retrospective observational cohort from a single institution

OBJECTIVES

Non-immune hydrops fetalis (NIHF) is the pathological accumulation of fluids in fetal compartments, without maternal isoimmunization. Fetal interventions (e.g. shunting, fetal paracentesis, fetal thoracocentesis, fetal pleurodesis) are used to alleviate fluid accumulations, but the outcome is uncertain because the underlying causes of NIHF vary. We aimed to explore the etiology and long-term outcome of NIHF after fetal intervention.

METHODS

This was a retrospective review of fetuses with NIHF, defined by the presence of fetal ascites, pleural or pericardial effusion, skin edema or cystic hygroma, or a combination of these features, who underwent intervention at our institution during the period 2012-2021. Clinical surveillance, genetic analysis and viral infection screening were used to define the etiology. Chart reviews and telephone interviews were conducted to assess the long-term outcomes.

RESULTS

In total, 55 fetuses were enrolled and 46 cases had final follow-up data after delivery. Etiology was identified in 33 cases, including four for which the underlying causes were not identified initially using small-gene-panel tests but which were later diagnosed with monogenic disorders by whole-exome sequencing (WES). Twenty-three cases with follow-up survived, having a follow-up period of 2-11 years at the time of writing, of which 17 were healthy. All 11 cases initially presenting as congenital chylothorax survived with favorable outcome.

CONCLUSIONS

The etiologies of NIHF are heterogeneous, and the long-term (spanning 2-11 years) outcome of fetal intervention varies, according to the underlying etiology, with cases caused by congenital chylothorax having the best prognosis. Genome-wide tests, such as WES, may be helpful in determining the underlying condition in cases caused by a genetic disorder, and this may affect fetal therapy approaches in the future. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Intrauterine enzyme replacement therapies for lysosomal storage disorders: Current developments and promising future prospects

Lysosomal storage disorders (LSDs) are a group of monogenic condition, with many characterized by an enzyme deficiency leading to the accumulation of an undegraded substrate within the lysosomes. For those LSDs, postnatal enzyme replacement therapy (ERT) represents the standard of care, but this treatment has limitations when administered only postnatally because, at that point, prenatal disease sequelae may be irreversible. Furthermore, most forms of ERT, specifically those administered systemically, are currently unable to access certain tissues, such as the central nervous system (CNS), and furthermore, may initiate an immune response. In utero enzyme replacement therapy (IUERT) is a novel approach to address these challenges evaluated in a first-in-human clinical trial for IUERT in LSDs (NCT04532047). IUERT has numerous advantages: in-utero intervention may prevent early pathology; the CNS can be accessed before the blood-brain barrier forms; and the unique fetal immune system enables exposure to new proteins with the potential to prevent an immune response and may induce sustained tolerance. However, there are challenges and limitations for any fetal procedure that involves two patients. This article reviews the current state of IUERT for LSDs, including its advantages, limitations, and potential future directions for definitive therapies.

Gene editing strategies to treat lysosomal disorders: The example of mucopolysaccharidoses

Lysosomal storage disorders are a group of progressive multisystemic hereditary diseases with a combined incidence of 1:4,800. Here we review the clinical and molecular characteristics of these diseases, with a special focus on Mucopolysaccharidoses, caused primarily by the lysosomal storage of glycosaminoglycans. Different gene editing techniques can be used to ameliorate their symptoms, using both viral and nonviral delivery methods. Whereas these are still being tested in animal models, early results of phase I/II clinical trials of gene therapy show how this technology may impact the future treatment of these diseases. Hurdles related to specific hard-to-reach organs, such as the central nervous system, heart, joints, and the eye must be tackled. Finally, the regulatory framework necessary to advance into clinical practice is also discussed.

Lysosomal storage disorders as an etiology of nonimmune hydrops fetalis: A systematic review

We performed a systematic review of the literature to evaluate the incidence and types of lysosomal storage disorders (LSD) in case series of nonimmune hydrops fetalis (NIHF). PubMed, Ovid, and clinicaltrials.gov were reviewed for case series evaluating the workup of NIHF diagnosed in utero or in the neonatal period in human subjects from 1979 to August 2020. Retrospective case series with at least five cases of fetal and/or neonatal NIHF with its workup mentioned were identified. Idiopathic NIHF was defined as NIHF without an apparent cause after initial standard-of-care workup. In total, 22 case series with 2678 total cases of NIHF were identified. The overall incidence of LSD was 6.6% (177/2663) in NIHF cases that were tested for any LSD, and 8.2% (177/2151) in idiopathic NIHF cases. The most common LSD identified in cases of NIHF were mucopolysaccharidosis type VII, galactosialidosis, infantile sialic acid storage disease, Gaucher disease, GM1 gangliosidosis, and sialidosis. More than 40% of the most common LSD causes of NIHF have a potential postnatal treatment. LSD testing for NIHF allows for early diagnosis, better counseling and appropriate management, planning for possible early treatment, and counseling for recurrence risk.

Value of Exome Sequencing in Diagnosis and Management of Recurrent Non-immune Hydrops Fetalis: A Retrospective Analysis

The purpose of the study was to use exome sequencing (ES) to study the contribution of single-gene disorders to recurrent non-immune hydrops fetalis (NIHF) and retrospectively evaluate the value of genetic diagnosis on prenatal management and pregnancy outcome. From January 2012 to October 2018, a cohort of 28 fetuses with recurrent NIHF was analyzed by trio ES. Fetuses with immune hydrops, non-genetic factors (including infection, etc.), karyotype, or CNV abnormalities were excluded. Variants were interpreted based on ACMG/AMP guidelines. Fetal therapy was performed on seven fetuses. Of the 28 fetuses, 10 (36%) were found to carry causal genetic variants (pathogenic or likely pathogenic) in eight genes (GBA, GUSB, GBE1, RAPSN, FOXC2, PIEZO1, LZTR1, and FOXP3). Five (18%) fetuses had variant(s) of uncertain significance (VUS). Of the 10 fetuses with definitive molecular diagnosis, five (50%) were diagnosed with inborn errors of metabolism. Among the seven fetuses who received fetal therapy, two had definitive molecular diagnosis and resulted in neonatal death. Among the remaining five fetuses with negative results, four had newborn survival and one had intrauterine fetal death. Trio ES could facilitate genetic diagnosis of recurrent NIHF and improve the prenatal management and pregnancy outcome.

Mucopolysaccharidosis type VII as a cause of recurrent Non-Immune Hydrops Fetalis: The first Tunisian case confirmed by Next-Generation Sequencing

Non-Immune Hydrops Fetalis (NIHF) is an intrauterine condition characterized by excessive fluid accumulation in at least two fetal compartments in the absence of maternal circulating red cell antibodies. It is associated with a poor prognosis and a wide etiological spectrum. Among the metabolic causes, Mucopolysaccharidosis type VII depicts the most frequent type of lysosomal storage disorders in the cause of NIHF. Nonetheless, it remains an ultra-rare disorder, as less than 150 cases have been reported in the literature. This rarity seems to be related to misdiagnosis since the underlying etiology remains unelusive in most cases of NIHF. In this report, we describe the first Tunisian case of Mucopolysaccharidosis type VII caused by a homozygous mutation in the GUSB gene confirmed by a Next-Generation Sequencing gene panel in a patient with recurrent NIHF.

Lysosomal storage disease spectrum in nonimmune hydrops fetalis: a retrospective case control study

OBJECTIVES

Nonimmune hydrops fetalis (NIHF) accounts for 90% of hydrops fetalis cases. About 15% to 29% of unexplained NIHF cases are caused by lysosomal storage diseases (LSD). We review the spectrum of LSD and associated clinical findings in NIHF in a cohort of patients referred to our institution.

METHODS

We present a retrospective case-control study of cases with NIHF referred for LSD biochemical testing at a single center. Cases diagnosed with LSD were matched to controls with NIHF and negative LSD testing and analyzed according to the STROBE criteria to the extent the retrospective nature of this study allowed.

RESULTS

Between January 2006 and December 2018, 28 patients with NIHF were diagnosed with a LSD. Eight types of LSD were diagnosed: galactosialidosis 8/28 (28.6%), sialic acid storage disease (SASD) 5/28 (17.9%), mucopolysaccharidosis VII 5/28 (17.9%), Gaucher 4/28 (14.3%), sialidosis 2/28 (7.1%), GM1 gangliosidosis 2/28 (7.1%), Niemann-Pick disease type C 1/28 (3.6%), and mucolipidosis II/III 1/28 (3.6%). Associated clinical features were hepatomegaly 16/21 (76.2%) vs 22/65 (33.8%), P < .05, splenomegaly 12/20 (60.0%) vs 14/58 (24.1%), P < .05, and hepatosplenomegaly 10/20 (50.0%) vs 13/58 (22.4%) P < .05.

CONCLUSION

The most common LSD in NIHF were galactosialidosis, SASD, mucopolysaccharidosis VII, and Gaucher disease. LSD should be considered in unexplained NIHF cases, particularly if hepatomegaly, splenomegaly, or hepatosplenomegaly is visualized on prenatal ultrasound.

No. 363-Investigation and Management of Non-immune Fetal Hydrops

OBJECTIVE

To describe the current investigation and management of non-immune fetal hydrops with a focus on treatable or recurring etiologies.

OUTCOMES

To provide better counselling and management in cases of prenatally diagnosed non-immune hydrops.

EVIDENCE

Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2017 using key words (non-immune hydrops fetalis, fetal hydrops, fetal therapy, fetal metabolism). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, observational studies, and significant case reports. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2017. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinicalpractice guideline collections, clinical trial registries, and national and international medical specialty societies.

BENEFITS, HARMS, AND COSTS

These guidelines educate readers about the causes of non-immune fetal hydrops and its prenatal counselling and management. It also provides a standardized approach to non-immune fetal hydrops, emphasizing the search for prenatally treatable conditions and recurrent genetic etiologies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.

RECOMMENDATIONS

Mucopolysaccharidoses: early diagnostic signs in infants and children

Mucopolysaccharidoses (MPS) comprise a group of lysosomal disorders that are characterized by progressive, systemic clinical manifestations and a coarse phenotype. The different types, having clinical, biochemical, and genetic heterogeneity, share key clinical features in varying combinations, including joint and skeletal dysplasia, coarse facial features, corneal clouding, inguinal or abdominal hernias, recurrent upper respiratory tract infections, heart valve disease, carpal tunnel syndrome, and variable neurological involvement. In the severe forms, these features usually appear in the first months of life, but a correct diagnosis is often reached later when suggestive signs are manifest. All MPS types may have severe or attenuated presentations depending on the residual enzymatic activity of the patient. Based on data from the literature and from personal experience, here we underline the very early signs of the severe forms which should alert the paediatrician on their first appearance. A few early signs are typical of MPS (i.e. gibbus) while many are unspecific (hernias, upper airway infections, organomegaly, etc.), and finding the association of many unspecific signs might prompt the paediatrician to search for a common cause and to carefully look for other more specific signs (gibbus and other skeletal deformities, heart murmur). We stress the need to increase awareness of MPS among paediatricians and other specialists to shorten the still existing diagnostic delay. A timely diagnosis is mandatory for the commencement of treatment as soon as possible, when available, to possibly obtain better results.

N° 363 - Évaluation et prise en charge de l'anasarque fœtoplacentaire non immune

OBJECTIF

Décrire les méthodes actuelles d'évaluation et de prise en charge de l'anasarque fœtoplacentaire non immune en mettant l'accent sur les étiologies traitables ou récurrentes. RéSULTATS: Offrir de meilleurs services de conseil et de prise en charge en cas d'anasarque fœtoplacentaire non immune diagnostiquée en période prénatale. DONNéES: La littérature publiée a été récupérée au moyen de recherches menées dans PubMed, MEDLINE, CINAHL, et la Bibliothèque Cochrane en 2017 à l'aide de mots-clés (« non-immune hydrops fetalis », « fetal hydrops », « fetal therapy », « fetal metabolism »). Les articles retenus portaient sur des revues systématiques, des essais cliniques contrôlés, randomisés ou non, des études observationnelles et des études de cas importantes. D'autres publications ont été repérées dans les bibliographies de ces articles. Aucune restriction de date ou de langue n'a été employée. Les recherches ont été mis à jour régulièrement, et les résultats ont été incorporés à la directive clinique jusqu'en septembre 2017. Nous avons également tenu compte de la littérature grise (non publiée) trouvée sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes liés aux technologies de la santé, dans des collections de directives cliniques et des registres d'essais cliniques, et obtenue auprès d'associations nationales et internationales de médecins spécialistes. AVANTAGES, INCONVéNIENTS ET COûTS: La présente directive clinique renseigne les lecteurs sur les causes de l'anasarque fœtoplacentaire non immune ainsi que sur son évaluation et sa prise en charge. Elle propose également une approche standardisée d'évaluation et de prise en charge, et met l'accent sur la recherche des conditions traitables en période prénatale et des étiologies génétiques récurrentes.

VALEURS

La qualité des données probantes a été évaluée en fonction des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs. RECOMMANDATIONS.

Non-immune fetal hydrops of metabolic origin: a case report and a review of the literature

Aim

To propose a diagnostic algorithm for non-immune fetal hydrops (NIFH) of metabolic origin based on a review of the literature and on the workup of a clinical case.

Background

The etiology of NIFH is complex and remains unexplained in 15%–25% of patients. The appropriate work up beyond an initial approach is still not well defined but it should include screening for metabolic conditions. Inborn errors of metabolism comprise a heterogeneous group of autosomal recessive rare inherited disorders, among which lysosomal storage disorder is the most common subtype.

Case description

We report a case of a 30-year-old pregnant, primiparous woman, referred to a tertiary hospital at 22 weeks of gestation because of a fetal hydrops. The second trimester obstetric ultrasound showed a hydrothorax and a large subcutaneous edema. At 30 weeks of gestation, the fetal health status deteriorated and a massive hepatomegaly was detected. The metabolic study of the amniotic fluid supernatant suggested a lysosomal disease. The ominous prognosis of the condition motivated the parents to opt for a termination of pregnancy. The autopsy study confirmed the existence of a metabolic disease.

Conclusion

The incidence of inborn errors of metabolism may be significantly higher in NIHF than reported previously. Consequently, an extensive investigation for the etiology of NIHF including the screening for metabolic disorders seems to be crucial for a definitive diagnosis.

Clinical relevance

Despite the lack of treatment options for the majority of these disorders, it is of great importance to follow an established workup, in order to identify the index case as soon as possible, as pregnancy management decisions and prenatal counselling in future pregnancies will depend on a more precise diagnosis.