Hyperphosphatasia With Intellectual Disability (Mabry Syndrome) due to Compound Heterozygous PIGO Variants: First Molecularly Characterized Case in French Guiana: A Case Report and Review of the Literature.
- 1Department of Medical Genetics University Hospital of French Guiana (Andrée Rosemon Hospital) Cayenne French Guiana.
- 2Department of Pediatric Emergency Medicine University Hospital of French Guiana (Andrée Rosemon Hospital) Cayenne French Guiana.
- 3Department of Pediatrics University Hospital of French Guiana (Andrée Rosemon Hospital) Cayenne French Guiana.
Abstract
Introduction
Hyperphosphatasia with intellectual disability syndrome (HPMRS), also known as Mabry syndrome, is a rare autosomal recessive disorder of glycosylphosphatidylinositol (GPI) anchor biosynthesis. Approximately 20 cases with pathogenic PIGO variants have been reported worldwide. This makes PIGO-related HPMRS one of the rarest molecularly defined subtypes of the disease.Case report
We report a male infant from French Guiana. He presented with neonatal tremors, global developmental delay with postural delay, and generalized tonic-clonic seizures with dystonic features. Symptoms began at 9 months and worsened by 13 months. Biochemical testing showed persistently elevated serum alkaline phosphatase (ALP 477 then 415 U/L; reference range 142-335 U/L). Trio whole-exome sequencing identified two compound heterozygous PIGO variants: c.839T > C (p.Met280Thr), inherited from the father, and c.590C > T (p.Pro197Leu), inherited from the mother. The diagnostic laboratory classified both as probably pathogenic (Class 4). Physical examination at 17 months showed growth retardation (height and weight at -2 SD) and a reducible umbilical hernia. There was no notable facial dysmorphism or limb anomaly.Conclusion
We report the first molecularly characterized case of PIGO-related HPMRS in French Guiana. The diagnosis combined clinical, biochemical, and molecular evaluation. This case shows that the PIGO phenotype extends beyond classic dysmorphic presentations.
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BibTeX
@article{diop2026hyperphosphatasia,
title = {{Hyperphosphatasia With Intellectual Disability (Mabry Syndrome) due to Compound Heterozygous PIGO Variants: First Molecularly Characterized Case in French Guiana: A Case Report and Review of the Literature.}},
author = {Mody Diop and Joddy Mafema Missindu and Narcisse Elenga},
journal = {Case reports in genetics},
year = {2026},
month = oct,
doi = {10.1155/crig/2289202},
url = {https://europepmc.org/article/MED/42903272},
note = {CC BY},
}
RIS
TY - JOUR
TI - Hyperphosphatasia With Intellectual Disability (Mabry Syndrome) due to Compound Heterozygous PIGO Variants: First Molecularly Characterized Case in French Guiana: A Case Report and Review of the Literature.
AU - Mody Diop
AU - Joddy Mafema Missindu
AU - Narcisse Elenga
PY - 2026
DA - 2026/10/19
JO - Case reports in genetics
DO - 10.1155/crig/2289202
UR - https://europepmc.org/article/MED/42903272
AB - Introduction Hyperphosphatasia with intellectual disability syndrome (HPMRS), also known as Mabry syndrome, is a rare autosomal recessive disorder of glycosylphosphatidylinositol (GPI) anchor biosynthesis. Approximately 20 cases with pathogenic PIGO variants have been reported worldwide. This makes PIGO-related HPMRS one of the rarest molecularly defined subtypes of the disease.Case report We report a male infant from French Guiana. He presented with neonatal tremors, global developmental delay with postural delay, and generalized tonic-clonic seizures with dystonic features. Symptoms began at 9 months and worsened by 13 months. Biochemical testing showed persistently elevated serum alkaline phosphatase (ALP 477 then 415 U/L; reference range 142-335 U/L). Trio whole-exome sequencing identified two compound heterozygous PIGO variants: c.839T > C (p.Met280Thr), inherited from the father, and c.590C > T (p.Pro197Leu), inherited from the mother. The diagnostic laboratory classified both as probably pathogenic (Class 4). Physical examination at 17 months showed growth retardation (height and weight at -2 SD) and a reducible umbilical hernia. There was no notable facial dysmorphism or limb anomaly.Conclusion We report the first molecularly characterized case of PIGO-related HPMRS in French Guiana. The diagnosis combined clinical, biochemical, and molecular evaluation. This case shows that the PIGO phenotype extends beyond classic dysmorphic presentations.
SN - 2090-6544
SN - 2090-6552
ER -