Encephalopathy due to beta-mercaptolactate-cysteine disulfiduria(MCDU)

MedGen UID:: 208661
•Concept ID:: C0796055
•: Disease or Syndrome

Synonyms:	DISULFIDURIA, MIXED; Mercaptolactate-cysteine disulfiduria
SNOMED CT:	Ampola syndrome (784373007); Beta-mercaptolactate cysteine disulfiduria (784373007)

Monarch Initiative:	MONDO:0009585
OMIM®:	249650
Orphanet:	ORPHA1035

Definition

An extremely rare disorder of methionine cycle and sulfur amino acid metabolism with characteristics of increased urine excretion of beta-mercaptolactate-cysteine disulfide (due to deficiency of mercaptopyruvate sulfurtransferase activity in erythrocytes), leading to a positive cyanide nitroprusside test. Association with intellectual disability, congenital lens dislocation, and behavioral abnormalities has been reported, however the causal link remains to be established. There have been no further descriptions in the literature since 1981. [from SNOMEDCT_US]

Clinical features

From HPO

Aminoaciduria

MedGen UID:: 116067
•Concept ID:: C0238621
•: Disease or Syndrome

An increased concentration of an amino acid in the urine.

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Hypokinesia

MedGen UID:: 39223
•Concept ID:: C0086439
•: Finding

Abnormally diminished motor activity. In contrast to paralysis, hypokinesia is not characterized by a lack of motor strength, but rather by a poverty of movement. The typical habitual movements (e.g., folding the arms, crossing the legs) are reduced in frequency.

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Bilateral tonic-clonic seizure

MedGen UID:: 141670
•Concept ID:: C0494475
•: Sign or Symptom

A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.

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Intellectual disability

MedGen UID:: 811461
•Concept ID:: C3714756
•: Mental or Behavioral Dysfunction

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

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High palate

MedGen UID:: 66814
•Concept ID:: C0240635
•: Congenital Abnormality

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).

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Depressed nasal bridge