Adams-Oliver Syndrome with Unusual Central Nervous System Findings and an Extrahepatic Portosystemic Shunt

Heterozygous NOTCH1 variants cause CNS immune activation and microangiopathy

NOTCH1 belongs to the NOTCH family of proteins that regulate cell fate and inflammatory responses. Somatic and germline NOTCH1 variants have been implicated in cancer, Adams-Oliver syndrome and cardiovascular defects. We describe seven unrelated patients grouped by the presence of leukoencephalopathy with calcifications and heterozygous de novo gain-of-function variants in NOTCH1. Immunologic profiling showed upregulated CSF IP-10, a cytokine secreted downstream of NOTCH1 signaling. Autopsy revealed extensive leukoencephalopathy and microangiopathy with vascular calcifications. This evidence implicates that heterozygous gain-of-function variants in NOTCH1 lead to a chronic CNS inflammatory response resulting in a calcifying microangiopathy with leukoencephalopathy. This article is protected by copyright. All rights reserved.

Presentation of Congenital Portosystemic Shunts in Children

Background: Congenital portosystemic shunts (CPSS) are rare vascular anomalies resulting in communications between the portal venous system and the systemic venous circulation, affecting an estimated 30,000 to 50,000 live births. CPSS can present at any age as a multi-system disease of variable severity mimicking both common and rare pediatric conditions. Case presentations: Case A: A vascular malformation was identified in the liver of a 10-year-old girl with tall stature, advanced somatic maturation, insulin resistance with hyperinsulinemia, hyperandrogenemia and transient hematuria. Work-up also suggested elevated pulmonary pressures. Case B: A young girl with trisomy 8 mosaicism with a history of neonatal hypoglycemia, transient neonatal cholestasis and tall stature presented newly increased aminotransferase levels at 6 years of age. Case C: A 3-year-old boy with speech delay, tall stature and abdominal pain underwent abdominal ultrasound (US) showing multiple liver nodules, diagnosed as liver hemangiomas by hepatic magnetic resonance imaging (MRI). Management and outcome: After identification of a venous malformation on liver Doppler US, all three patients were referred to a specialized liver center for further work-up within 12 to 18 months from diagnosis. Angio-computed tomography (CT) scan confirmed the presence of either an intrahepatic or extrahepatic CPSS with multiples liver nodules. All three had a hyperintense signal in the globus pallidus on T1 weighted cerebral MRI. Right heart catheterization confirmed pulmonary hypertension in cases A and C. Shunts were closed either using an endovascular or surgical approach. Liver nodules were either surgically removed if there was a risk of malignant degeneration or closely monitored by serial imaging when benign. Conclusion: These cases illustrate most of the common chief complaints and manifestations of CPSS. Liver Doppler US is the key to diagnosis. Considering portosystemic shunts in the diagnostic work-up of a patient with unexplained endocrine, liver, gastro-intestinal, cardiovascular, hematological, renal or neurocognitive disorder is important as prompt referral to a specialized center may significantly impact patient outcome.

Novel compound heterozygous mutations of the DOCK6 gene in a familial case of Adams-Oliver syndrome 2

INTRODUCTION

Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the combination of aplasia cutis congenita of the scalp vertex and terminal transverse limb defects. DOCK6 (Dedicator of cytokinesis 6) is one of the six identified AOS genes.

METHODS

We performed targeted next-generation sequencing (NGS) of a child with an AOS phenotype. Sanger DNA sequencing further validated her lineal consanguinity. To explore the pathological features of the mutation, a minigene assay was used to investigate the effects of the mutation on splicing.

RESULTS

Two compound heterozygous DOCK6 mutations (c.4106+2T>C and c.3063 C>G (p.Y1021*)) were identified in this family, and both mutations have not been reported previously. Sanger DNA sequencing indicated that the mutations were inherited maternally and paternally, respectively. The results of the minigene assay showed that the c.4106+2T>C mutation resulted in aberrant splicing and caused a four-nucleotide insertion in the transcript and a premature stop codon.

CONCLUSIONS

Our findings expanded the number of reported cases of this rare disease and the mutation spectrum of DOCK6 mutations, which can serve as the basis for prenatal diagnosis and genetic counseling.

Congenital portosystemic shunts: diagnosis and treatment

Congenital portosystemic shunts (CPSS) are rare vascular malformations that create an abnormal connection between portal and systemic veins resulting in complete or partial diversion of the portal flow away from the liver to the systemic venous system. Different anatomic types exist and several classifications have been proposed. They can be associated with other malformations especially cardiac and heterotaxia. The main complications include hepatic encephalopathy, liver tumors, portopulmonary hypertension, and pulmonary arteriovenous shunts. Diagnosis relies on imaging, and prenatal diagnosis is possible. Spontaneous closure of the CPSS is possible in some anatomic forms during the first year of life. When the CPSS remains patent, radiologic or surgical closure of the CPSS may prevent, resolve, or stabilize complications. Interventional radiology plays a key role for both the preoperative evaluation with occlusion test to assess the exact anatomy and to measure portal pressure after occlusion of the CPSS. Endovascular closure is the first option for treatment when possible.