Miscellaneous Amino Acid and Organic Acid Metabolism Disorders

Sarcosinemia (268900*)

Sarcosine dehydrogenase

Biochemical profile: Elevated plasma sarcosine

Clinical features: Benign; intellectual disability reported

Treatment: None needed

D-glyceric aciduria (220120*)

D-glycerate kinase

Biochemical profile: Elevated urinary D-glyceric acid

Clinical features: Chronic acidosis, hypotonia, seizures, intellectual disability

Treatment: Bicarbonate or citrate for acidosis

Hartnup disease (234500*)

System B(0) neutral amino acid transporter

Biochemical profile: Neutral aminoaciduria

Clinical features: Atrophic glossitis, photodermatitis, intermittent ataxia, hypertonia, seizures, psychosis

Treatment: Nicotinamide

Cystinuria (220100*)

Renal dibasic amino acid transporter

Biochemical profile:

Clinical features: Nephrolithiasis, increased risk of impaired cerebral function

Treatment:

Type I

Heavy subunit

Types II and III

Light subunit

Iminoglycinuria (242600*)

Biochemical profile:

Clinical features: Probably benign

Treatment: None needed

Guanidinoacetate methyltransferase deficiency (601240*)

Guanidinoacetate methyltransferase

Biochemical profile: Elevated guanidinoacetate, decreased creatine and phosphocreatine

Clinical features: Developmental delay, hypotonia, extrapyramidal movements, seizures, autistic behavior

Treatment: Creatine supplementation

Cystinosis

See table Lysosomal Transport Defects

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