There are currently no additional known synonyms for this rare genetic disease.

Mandel et al. (2016) described four patients from two unrelated families with homozygous mutations in HTRA2. Consistent clinical features included hypertonia alternating with hypotonia, tremor, dystonic posturing, disappearing spontaneous movements, lack of acquisition of milestones, absent response to external stimuli, intractable seizures, and sensorineural deafness. Additional features were bradycardia at birth, vertical plantar creases, butterfly-shaped vertebrae, microcephaly, dysautonomia (manifested as episodic hyperthermia), and EEG abnormalities compatible with myoclonic encephalopathy. Brain MRI showed thin corpus callosum, ventriculomegaly, bilateral holohemispheric hygromas, and cerebral volume loss; SPECT MRI showed low n-acetylaspartate/creatine (NAA/Cr) ratio, increased choline and myo-inositol to creatine ratio, and abnormal lactate signal. Laboratory tests showed intermittent neutropenia, increased excretion of 3-methylglutaconic (3-MGA) and 3-methylglutaric acids in urinary organic acid analysis. All patients died prematurely.
Oláhová et al. (2017) described four patients from two unrelated consanguineous families with the same condition. The clinical characteristics were very similar to the previously reported. Additional characteristics included bilateral cataracts, hypoglycemia, apneas, central respiratory failure, dysphagia, poor cardiac contractility, and patent ductus arteriosus.
Two unrelated patients were described by Kovacs-Nagy et. al. (2018). Clinical characteristics included neonatal movement disorder with epilepsy and 3-methylglutaconic aciduria. The authors reviewed 11 published cases.

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* This information is courtesy of the L M D.

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The syndrome is inherited in the following inheritance pattern/s:

Autosomal Recessive - Autosomal recessive inheritance means an affected individual receives one copy of a mutated gene from each of their parents, giving them two copies of a mutated gene. Parents, who carry only one copy of the gene mutation will not generally show any symptoms but have a 25% chance of passing the copies of the gene mutations onto each of their children.

In some cases, a genetic syndrome may be the result of a de-novo mutation and the first case in a family. In this case, this is a new gene mutation that occurs during the reproductive process.

OMIM Number - 617248 (please check the OMIM page for updated information)

The syndrome can be caused by mutations in the following gene/s location/s:
HTRA2 - 2p13.1

What are the main symptoms of 3-METHYLGLUTACONIC ACIDURIA, TYPE VIII; MGCA8?

The typical symptoms of the syndrome are:

How does someone get tested for 3-METHYLGLUTACONIC ACIDURIA, TYPE VIII; MGCA8?

The initial testing for 3-METHYLGLUTACONIC ACIDURIA, TYPE VIII; MGCA8 can begin with facial genetic analysis screening, through the FDNA Telehealth telegenetics platform, which can identify the key markers of the syndrome and outline the type of genetic testing needed. A consultation with a genetic counselor and then a geneticist will follow.

Based on this clinical consultation with a geneticist, the different options for genetic testing will be shared and consent will be sought for further testing.

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