Expanding the Phenotype of STAMBP-Related Microcephaly-Capillary Malformation Syndrome.

Biallelic variants in the STAMBP gene are known to cause Microcephaly-capillary malformation syndrome (MICCAP syndrome). Here we report an 18-month-old female with a novel splice site variant, c.376-1G>A in intron-4, with the phenotype of a patient who presented to us with fetal onset growth retardation, developmental delay, drug-resistant seizures, multiple capillary malformations, dysmorphism, tone abnormalities, and distal skeletal and nail abnormalities. Functional studies by RNA analysis and quantitative polymerase chain reaction (qPCR) showed that the variant leads to loss of function. The clinical features noted in this child strongly overlapped with the phenotypes reported in the literature, except for absent dentition and retinal dystrophy-like findings on fundus examination. A total of 22 cases have been reported in the literature. We present a detailed description of an Indian child, expanding the clinical and molecular spectrum of STAMBP-related disease.