HOMOCYSTINURIA, CYSTATHIONINE BETA-SYNTHASE DEFICIENCY (CBS)

Question 1

What is  HOMOCYSTINURIA, CYSTATHIONINE BETA-SYNTHASE DEFICIENCY  (CBS)?

Accepted Answer

rare - 1:1800 (Qatar) - 1:60000 (Ireland) - 1:146000 (Japan)
autosomal recessive

50% pyridoxine-responsive patients

CBS deficient individuals undergoing betaine supplementation without sufficient dietary methionine restriction

can develop severe hypermethioninemia and brain edema [Schwahn BC et al 2020]

Question 2

Gibt es eine deutsche Bezeichnung?

Accepted Answer

Homocystinurie durch Cystathionin-beta-Synthase-Mangel; Homozystinurie, klassische

Question 3

What is the link to OMIM ?

Accepted Answer

OMIN 236200

Question 4

Which enzymes are involved?

Accepted Answer

Cystathionine beta-synthase

Disease	HOMOCYSTINURIA, CYSTATHIONINE BETA-SYNTHASE DEFICIENCY (CBS)
Synonym	CBS DEFICIENCY
OMIM	236200 OMIM = Online Mendelian Inheritance of Men
Orphanet	394
Protein (UniProt)	Cystathionine beta-synthase
ExPASy	4.2.1.22
Gene locus	21q22.3 Detail information to gene locus by the National Center for Biotechnology Information NCBI: Cystathionine beta-synthase
ICD	E72.1
Summary	rare - 1:1800 (Qatar) - 1:60000 (Ireland) - 1:146000 (Japan) autosomal recessive 50% pyridoxine-responsive patients CBS deficient individuals undergoing betaine supplementation without sufficient dietary methionine restriction can develop severe hypermethioninemia and brain edema [Schwahn BC et al 2020]
Laboratory findings	Betaine normal/inc (urine) Ceruloplasmin inc (plasma) Copper inc (plasma) Cystine dec (plasma) Homocysteine inc (urine) Homocysteine inc (plasma) L-Homocystine inc (urine) L-Homocystine inc (plasma) Methionine inc (plasma) Methionine inc (urine) Ornithine inc (plasma) S-Adenosylhomocysteine inc (plasma) S-Adenosylmethionine inc (plasma)
Symptoms	arachnodyctyly arthritis behavior, abnormal or bizarre, confusion depression developmental delay dislocated lens (ectopia lentis) dystonia inguinal hernia intellectual disability/intellectual developmental disorder malar flush Marfanoid features osteoporosis pes cavus seizures skeletal changes, skeletal abnormalities skoliosis, kyphoskoliosis thromboembolism aortic valvular disease ataxia cerebral vascular disease chest deformity Coagulopathy/Coagulation factors EEG abnormalities [-] genu valgum glaucoma hair, abnormal (thin, brittle, fine) hand and/or feet deformities hypopigmentation liver, fatty mental retardation myoclonus myopia onset, adolescent onset, childhood optic atrophy pancreatitis retinal or macular degeneration strokelike episodes tall stature X-ray, abnormalities