Symmetrical thalamic calcifications in a monozygotic twin: case report and literature review

Symmetrical thalamic calcification: A trio whole exome sequencing negative series

Symmetrical thalamic calcification or bilateral symmetrical thalamic gliosis presents at delivery with hypertonia, fixed flexion contractures and prominent bulbar signs, without preceding perinatal asphyxia. At post-mortem, there is evidence of bilateral symmetrical selective thalamic neuronal encrustation and gliosis. To date, 27 cases are published with no underlying diagnosis identified. Two affected children from singleton pregnancies were reported and therefore, a genetic cause proposed. No previous reports have performed genetic testing to confirm or reject this hypothesis. We report three additional cases of this rare condition, expanding the clinical and pathological phenotype. We performed trio whole exome sequencing, the first in this cohort of patients, and did not identify a pathogenic variant. As postulated in the original report, the likely underlying mechanism is antenatal hypoxia in the third trimester.

[Cerebral palsy and perinatal asphyxia (I--diagnosis)]

Cerebral palsy (CP) is a group of disorders of the development of movement and posture, causing activity limitations, that are attributed to nonprogressing disturbances that occurred in the developing fetal or infant brain. The motor abnormalies are often accompanied by disturbances of sensation, perception, cognition, behavior and/or by a seizure disorder. The prevalence of CP has not decreased in developed countries over the past 30 years, despite the widespread use of electronic fetal heart rate monitoring and a 5- to 6-fold increase in the cesarean delivery rate. In the term newborn, CP may be attributed to perinatal asphyxia in case of metabolic acidosis in the cord blood (pH<7,00 and base deficit>12 mmol/L), followed by a moderate or severe neonatal encephalopathy within 24 hours and a further neurological impairement characterized by spastic quadriplegia and dyskinesia/dystonia. Dating the time of fetal asphyxia during delivery is possible when there are acute catastrophic complications during labor and unexpected acute or progressive fetal heart rate anomalies after a normal admission test, when there is a need for intensive neonatal resuscitation, a multi-organ failure within 72 hours of birth and visualization of acute non focal cerebral abnormalities, mainly by early magnetic resonance imaging (MRI). MRI sequences show either a brain-damaged pattern of the central basal ganglia, thalami and posterior limbs of internal capsules with relative cortical sparing, in acute, near-total asphyxial insults manifested by a continuous bradycardia or a pattern of cortical injury in the watershed zones and relative sparing of the central grey matter, in prolonged partial asphyxia, manifested by late or atypical variable decelerations with progressive fetal tachycardia, loss of reactivity and absent fluctuation. Prolongation of either type of asphyxial insult results in more global brain damage. In order to differentiate a CP occurring after perinatal asphyxia from other neurological sequelae in relation with infection, hemorrhage, stroke, malformations, genetic or metabolic diseases, it is essential that a definitive information from the brain by MRI and an extensive histological examination of the placenta are at disposal.