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Mitochondrial complex 1 deficiency, nuclear type 36(MC1DN36)

MedGen UID:
1773965
Concept ID:
C5436935
Disease or Syndrome
Synonym: MITOCHONDRIAL COMPLEX I DEFICIENCY, NUCLEAR TYPE 36
 
Gene (location): NDUFC2 (11q14.1)
 
Monarch Initiative: MONDO:0030902
OMIM®: 619170

Definition

Mitochondrial complex I deficiency nuclear type 36 (MC1DN36) is an autosomal recessive metabolic disorder characterized by global developmental delay, hypotonia, and failure to thrive apparent from infancy or early childhood. Affected individuals usually do not acquire ambulation, show progressive spasticity, and have impaired intellectual development with absent speech. More variable features may include pale optic discs, poor eye contact, seizures, and congenital heart defects. Laboratory studies show increased serum lactate; metabolic acidosis may occur during stress or infection. Brain imaging shows T2-weighted abnormalities in the basal ganglia and brainstem, consistent with a clinical diagnosis of Leigh syndrome (see 256000). Patient tissue showed isolated mitochondrial complex I deficiency. Death may occur in childhood (Alahmad et al., 2020). For a discussion of genetic heterogeneity of mitochondrial complex I deficiency, see 252010. [from OMIM]

Clinical features

From HPO
Limb hypertonia
MedGen UID:
333083
Concept ID:
C1838391
Finding
Cardiomegaly
MedGen UID:
5459
Concept ID:
C0018800
Finding
Increased size of the heart, clinically defined as an increased transverse diameter of the cardiac silhouette that is greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio) on a posterior-anterior projection of a chest radiograph or a computed tomography.
Perimembranous ventricular septal defect
MedGen UID:
87490
Concept ID:
C0344925
Congenital Abnormality
A ventricular septal defect that is confluent with and involves the membranous septum and is bordered by an atrioventricular valve, not including the type 3 VSDs.
Periventricular leukomalacia
MedGen UID:
6072
Concept ID:
C0023529
Disease or Syndrome
Periventricular leukomalacia is characterized by diffuse injury of deep cerebral white matter, accompanied in its most severe form by focal necrosis. The neuropathologic hallmarks of PVL are microglial activation and focal and diffuse periventricular depletion of premyelinating oligodendroglia.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterised by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
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.
Reduced eye contact
MedGen UID:
303190
Concept ID:
C1445953
Finding
Difficulty in looking at another person in the eye.
Developmental regression
MedGen UID:
324613
Concept ID:
C1836830
Disease or Syndrome
Loss of developmental skills, as manifested by loss of developmental milestones.
Enlarged cisterna magna
MedGen UID:
344031
Concept ID:
C1853377
Finding
Increase in size of the cisterna magna, one of three principal openings in the subarachnoid space between the arachnoid and pia mater, located between the cerebellum and the dorsal surface of the medulla oblongata.
Axial hypotonia
MedGen UID:
342959
Concept ID:
C1853743
Finding
Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Recurrent lower respiratory tract infections
MedGen UID:
756211
Concept ID:
C3163798
Disease or Syndrome
An increased susceptibility to lower respiratory tract infections as manifested by a history of recurrent lower respiratory tract infections.
Hyperprolinemia
MedGen UID:
75690
Concept ID:
C0268528
Disease or Syndrome
An increased concentration of proline in the blood.
Hyper-beta-alaninemia
MedGen UID:
75702
Concept ID:
C0268630
Disease or Syndrome
An increased concentration of alanine in the blood.
Increased serum lactate
MedGen UID:
332209
Concept ID:
C1836440
Finding
Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35).
Optic disc pallor
MedGen UID:
108218
Concept ID:
C0554970
Finding
A pale yellow discoloration of the optic disk (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression.
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.

Recent clinical studies

Clinical prediction guides

von Kleist-Retzow JC, Cormier-Daire V, de Lonlay P, Parfait B, Chretien D, Rustin P, Feingold J, Rötig A, Munnich A
Am J Hum Genet 1998 Aug;63(2):428-35. doi: 10.1086/301957. PMID: 9683589Free PMC Article

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