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Mitochondrial DNA depletion syndrome 9(MTDPS9)

MedGen UID:
462826
Concept ID:
C3151476
Disease or Syndrome
Synonyms: Fatal Infantile Lactic Acidosis; Mitochondrial DNA depletion syndrome 9 (encephalomyopathic with methylmalonic aciduria); MTDPS9; SUCLG1-Related Mitochondrial DNA Depletion Syndrome, Encephalomyopathic Form, with Mild Methylmalonic Aciduria
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): SUCLG1 (2p11.2)
 
Monarch Initiative: MONDO:0009504
OMIM®: 245400
Orphanet: ORPHA17

Disease characteristics

SUCLG1-related mitochondrial DNA (mtDNA) depletion syndrome, encephalomyopathic form with methylmalonic aciduria is characterized in the majority of affected newborns by hypotonia, muscle atrophy, feeding difficulties, and lactic acidosis. Affected infants commonly manifest developmental delay / cognitive impairment, growth retardation / failure to thrive, hepatopathy, sensorineural hearing impairment, dystonia, and hypertonia. Notable findings in some affected individuals include hypertrophic cardiomyopathy, epilepsy, myoclonus, microcephaly, sleep disturbance, rhabdomyolysis, contractures, hypothermia, and/or hypoglycemia. Life span is shortened, with median survival of 20 months. [from GeneReviews]
Authors:
Ayman W El-Hattab  |  Fernando Scaglia   view full author information

Additional description

From OMIM
Mitochondrial DNA depletion syndrome-9 (MTDPS9) is a severe autosomal recessive disorder characterized by infantile onset of hypotonia, lactic acidosis, severe psychomotor retardation, progressive neurologic deterioration, and excretion of methylmalonic acid. Some patients die in early infancy (summary by Rouzier et al., 2010). For a discussion of genetic heterogeneity of mtDNA depletion syndromes, see MTDPS1 (603041).  http://www.omim.org/entry/245400

Clinical features

From HPO
Methylmalonic aciduria
MedGen UID:
343266
Concept ID:
C1855119
Disease or Syndrome
Increased concentration of methylmalonic acid in the urine.
Lacticaciduria
MedGen UID:
871116
Concept ID:
C4025585
Finding
An increased concentration of lactic acid in the urine.
Fetal growth restriction
MedGen UID:
4693
Concept ID:
C0015934
Pathologic Function
An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.
Growth delay
MedGen UID:
99124
Concept ID:
C0456070
Pathologic Function
A deficiency or slowing down of growth pre- and postnatally.
Failure to thrive
MedGen UID:
746019
Concept ID:
C2315100
Disease or Syndrome
Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Hearing impairment
MedGen UID:
235586
Concept ID:
C1384666
Disease or Syndrome
A decreased magnitude of the sensory perception of sound.
Intellectual disability, severe
MedGen UID:
48638
Concept ID:
C0036857
Mental or Behavioral Dysfunction
Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34.
Encephalopathy
MedGen UID:
39314
Concept ID:
C0085584
Disease or Syndrome
Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state.
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Persistent head lag
MedGen UID:
256151
Concept ID:
C1141883
Finding
The Premie-Neuro and the Dubowitz Neurological Examination score head lag in the same manner. Scoring for both is as follows
Increased CSF lactate
MedGen UID:
257904
Concept ID:
C1167918
Finding
Increased concentration of lactate in the cerebrospinal fluid.
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
Elevated brain lactate level by MRS
MedGen UID:
868368
Concept ID:
C4022762
Finding
An increase in the level of lactate in the brain identified by magnetic resonance spectroscopy (MRS).
Focal T2 hyperintense basal ganglia lesion
MedGen UID:
892349
Concept ID:
C4024926
Finding
A lighter than expected T2 signal on magnetic resonance imaging (MRI) of the basal ganglia. This term refers to a localized hyperintensity affecting a particular region of the basal ganglia.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Muscular atrophy
MedGen UID:
892680
Concept ID:
C0541794
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Poor head control
MedGen UID:
322809
Concept ID:
C1836038
Finding
Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months.
Generalized neonatal hypotonia
MedGen UID:
336857
Concept ID:
C1845123
Finding
Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period and affecting the entire musculature.
Axial hypotonia
MedGen UID:
342959
Concept ID:
C1853743
Finding
Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.
Infantile muscular hypotonia
MedGen UID:
395993
Concept ID:
C1860834
Finding
Muscular hypotonia (abnormally low muscle tone) manifesting in infancy.
Depletion of mitochondrial DNA in muscle tissue
MedGen UID:
867163
Concept ID:
C4021521
Finding
Respiratory insufficiency
MedGen UID:
11197
Concept ID:
C0035229
Pathologic Function
Impairment of gas exchange within the lungs secondary to a disease process, neoplasm, or trauma, possibly resulting in hypoxia, hypercarbia, or both, but not requiring intubation or mechanical ventilation. Patients are normally managed with pharmaceutical therapy, supplemental oxygen, or both.
Respiratory failure
MedGen UID:
257837
Concept ID:
C1145670
Disease or Syndrome
A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits.
Neonatal respiratory distress
MedGen UID:
924182
Concept ID:
C4281993
Finding
Respiratory difficulty as newborn.
Lactic acidosis
MedGen UID:
1717
Concept ID:
C0001125
Disease or Syndrome
An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.
Hypoglycemia
MedGen UID:
6979
Concept ID:
C0020615
Disease or Syndrome
A decreased concentration of glucose in the blood.
Hypothermia
MedGen UID:
5720
Concept ID:
C0020672
Finding
Reduced body temperature due to failed thermoregulation.
Elevated circulating aspartate aminotransferase concentration
MedGen UID:
57497
Concept ID:
C0151904
Finding
The concentration of aspartate aminotransferase (AST) in the blood circulation is above the upper limit of normal.
Elevated circulating alanine aminotransferase concentration
MedGen UID:
57740
Concept ID:
C0151905
Finding
An abnormally high concentration in the circulation of alanine aminotransferase (ALT).
Hyperglycinemia
MedGen UID:
82817
Concept ID:
C0268559
Disease or Syndrome
An elevated concentration of glycine in the blood.
Hypertaurinemia
MedGen UID:
1690964
Concept ID:
C5139566
Finding
An increased amount of taurine in the blood.
Elevated lactate:pyruvate ratio
MedGen UID:
1717835
Concept ID:
C5397670
Finding
An abnormal increase in the molar ratio of lactate to pyruvate in the blood circulation.
Hyperhidrosis
MedGen UID:
5690
Concept ID:
C0020458
Finding
Abnormal excessive perspiration (sweating) despite the lack of appropriate stimuli like hot and humid weather.
Decreased activity of mitochondrial complex I
MedGen UID:
393796
Concept ID:
C2677650
Finding
A reduction in the activity of the mitochondrial respiratory chain complex I, which is part of the electron transport chain in mitochondria.
Decreased activity of mitochondrial complex III
MedGen UID:
460434
Concept ID:
C3149083
Finding
A reduction in the activity of the mitochondrial respiratory chain complex III, which is part of the electron transport chain in mitochondria.
Decreased activity of mitochondrial complex IV
MedGen UID:
866520
Concept ID:
C4020800
Finding
A reduction in the activity of the mitochondrial respiratory chain complex IV, which is part of the electron transport chain in mitochondria.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Mitochondrial DNA depletion syndrome 9 in Orphanet.

Recent clinical studies

Diagnosis

Chen YM, Chen W, Xu Y, Lu CS, Zhu MM, Sun RY, Wang Y, Chen Y, Shi J, Wang D
Mol Genet Genomic Med 2022 Sep;10(9):e2010. Epub 2022 Jun 28 doi: 10.1002/mgg3.2010. PMID: 35762302Free PMC Article

Prognosis

Chen YM, Chen W, Xu Y, Lu CS, Zhu MM, Sun RY, Wang Y, Chen Y, Shi J, Wang D
Mol Genet Genomic Med 2022 Sep;10(9):e2010. Epub 2022 Jun 28 doi: 10.1002/mgg3.2010. PMID: 35762302Free PMC Article

Clinical prediction guides

Chen YM, Chen W, Xu Y, Lu CS, Zhu MM, Sun RY, Wang Y, Chen Y, Shi J, Wang D
Mol Genet Genomic Med 2022 Sep;10(9):e2010. Epub 2022 Jun 28 doi: 10.1002/mgg3.2010. PMID: 35762302Free PMC Article

Supplemental Content

Table of contents

    Clinical resources

    Practice guidelines

    Curated

    • ACMG ACT, 2022
      American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated C3 Acylcarnitine, Propionic Acidemia (PA) and Methylmalonic Acidemia (MMA), 2022
    • ACMG Algorithm, 2022
      American College of Medical Genetics and Genomics, Algorithm, Propionic and Methylmalonic Acidemia: C3 Elevated, 2022

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