Uterus infantilis: a novel phenotype associated with AARS2 new genetic variants. A case report

Objectives

To report the first Mexican case with two novel AARS2 mutations causing primary ovarian failure, uterus infantilis, and early-onset dementia secondary to leukoencephalopathy.

Methods

Detailed clinical, clinimetric, neuroimaging features, muscle biopsy with biochemical assays of the main oxidative phosphorylation complexes activities, and molecular studies were performed on samples from a Mexican female.

Results

We present a 41-year-old female patient with learning difficulties since childhood and primary amenorrhea who developed severe cognitive, motor, and behavioral impairment in early adulthood. Neuroimaging studies revealed frontal leukoencephalopathy with hypometabolism at the fronto-cerebellar cortex and caudate nucleus. Uterus infantilis was detected on ultrasound study. Clinical exome sequencing identified two novel variants, NM_020745:c.2864G>A (p.W955^*) and NM_020745:c.1036C>A (p.P346T, p.P346Wfs^*18), in AARS2. Histopathological and biochemical studies on muscle biopsy revealed mitochondrial disorder with cytochrome C oxidase (COX) deficiency.

Conclusions

Several adult-onset cases of leukoencephalopathy and ovarian failure associated with AARS2 variants have been reported. To our best knowledge, none of them showed uterus infantilis. Here we enlarge the genetic and phenotypic spectrum of AARS2-related dementia with leukoencephalopathy and ovarian failure and contribute with detailed clinical, clinometric, neuroimaging, and molecular studies to disease and novel molecular variants characterization.

[Neuropsychiatric aspects of anti-NMDA receptor encephalitis]

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a potentially lethal clinical entity that belongs to the group of antibody-mediated encephalitis against synaptic proteins. It shows IgG antibodies against the NR1 subunit of the NMDA receptor (NMDA-R), which have been associated with psychiatric and neurological symptoms that develop in stages in the course of the disease. The predominance of neuropsychiatric symptoms in the early stages of the disease results in an increased number of patients that search for psychiatric evaluation as their first contact with the health system. For this reason, it is vital for physicians to recognize this entity as an important differential diagnosis in their clinical practice because, despite the severity of this condition, more than 75 % of patients achieve a substantial recovery with appropriate and timely treatment. We present a review of the literature on this disease, with special emphasis on the neuropsychiatric aspects.

[Autoinmune psychosis]

With the advent of the description of autoimmune encephalitis by different neuronal cell-surface antibodies (anti-NMDAr, among others) and that psychosis may be the only manifestation without neurological symptoms (epilepsy, movement disorders, autonomic dysfunction, altered state of consciousness) in 6.5 % of patients, the term "autoimmune psychosis" has become remarkably interesting among researchers. In 2020, an international consensus for the description and diagnostic approach of autoimmune psychosis was created. Through this consensus, by taking different criteria into account, the definition of autoimmune psychosis was proposed at different degrees of certainty (possible, probable, and defined). The purpose of these criteria is to underpin the autoimmune origin in patients who present psychosis with atypical characteristics, thus justifying the realization of laboratory studies and complementary clinical tests (lumbar puncture, electroencephalogram, and magnetic resonance imaging of the brain); in addition, these criteria are applied in patients with psychosis without neurological symptoms that do not fully meet the criteria of autoimmune encephalitis. As in autoimmune encephalitis, the early initiation of immunotherapy has a direct impact on the functional prognosis of patients, so an early initiation of treatment must be considered in clinical scenarios of probable or definite autoimmune psychosis.

[Programa de detección del alelo APOE-E4 en adultos mayores mexicanos con deterioro cognitivo]

Introduction

In Mexico, the prevalence of neurocognitive disorders (NCDs) has increased in parallel with the increase in life expectancy. The E4 allele of the gene that encodes apolipoprotein E (APOE) is the main genetic risk factor for cognitive impairment.

Objective

To replicate the association of APOE-E4 allele with neurocognitive impairment in a Mexican population, as well as to implement a genetic risk-detection program with the APOE-E4 allele.

Method

A program was structured for the detection of APOE-E4 allele risk in different recruiting centers from the central zone of the Mexican Republic, with three stages: recruitment and selection of candidates for the detection of the risk-allele, genetic risk analysis and delivery of results.

Results

In the genetic-association study to replicate the association with neurocognitive disorders by means of multivariate logistic models, the APOE-E4 allele increased the risk for cognitive impairment in the Mexican populations by approximately 6 % (OR: 5.83, p = 0.0025). In addition, 367 genetic risk results were delivered.

Conclusions

The present program is the first one to be implemented in Mexico with the purpose to inform on a genetic risk factor for neurocognitive disorders in several centers of the country.