Aminoacidopathy
Gene: PPM1K
New literature identifies 8 yo male child presenting with mild dysmorphic features, delayed speech, relative microcephaly, and overweight, all considered familial phenotypic traits.
Laboratory findings revealed mildly elevated plasma branched-chain amino acids, mild lactic acidemia, and a slight increase in urinary keto acids. Testing identified homozygous missense variant in PPM1K - c.925A>G p.(Ile309Val). No functional studies conducted. In silico predicts AA substitution to have destabilising impact on protein.
3 individuals now reported in literature with mild findings related to MSUD BCAA levels. Adequate evidence to include in panel?Created: 2 Dec 2025, 4:30 p.m. | Last Modified: 2 Dec 2025, 4:31 p.m.
Panel Version: 1.138
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Maple syrup urine disease, mild variant, MIM#615135
Publications
PMID: 36706222 reported a patient with MSUD with mild findings and elevated BCAA levels carrying a novel homozygous start-loss variant in PPM1K. (PMID: 36706222).Created: 30 Jan 2023, 12:13 p.m. | Last Modified: 30 Jan 2023, 12:13 p.m.
Panel Version: 1.1
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Maple syrup urine disease (MSUD)
Publications
Additional individual reported in PMID 40047138 noted. However, variant is homozygous missense and thus a VOUS.Created: 7 Dec 2025, 1:09 p.m. | Last Modified: 7 Dec 2025, 1:09 p.m.
Panel Version: 1.138
Single family reported.Created: 19 Apr 2022, 4:44 p.m. | Last Modified: 19 Apr 2022, 4:44 p.m.
Panel Version: 0.13064
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Maple syrup urine disease, mild variant, MIM#615135
Publications
Phenotypes for gene: PPM1K were changed from maple syrup urine disease, mild variant MONDO:0014057 to Maple syrup urine disease, mild variant MONDO:0014057
Publications for gene: PPM1K were set to 29152456; 23086801
Gene: ppm1k has been classified as Amber List (Moderate Evidence).
Gene: ppm1k has been classified as Red List (Low Evidence).
Publications for gene: PPM1K were set to 29152456
Gene: ppm1k has been classified as Red List (Low Evidence).
gene: PPM1K was added gene: PPM1K was added to Disorders of branched chain amino acid metabolism. Sources: Expert Review Green Mode of inheritance for gene: PPM1K was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: PPM1K were set to 29152456 Phenotypes for gene: PPM1K were set to maple syrup urine disease, mild variant MONDO:0014057