Facial Phenotypic Pattern in Severe Congenital Neutropenia Type 4 (G6PC3 Deficiency): Description and Clinical Value

Severe congenital neutropenia type 4 (SCN4) is an autosomal recessive disorder caused by mutations in the third subunit of the enzyme glucose-6-phosphatase (G6PC3). Patients with mutations in G6PC3 suffer from congenital neutropenia and additional complex developmental abnormalities. Previous reports have found that SCN4 has recognizable dysmorphic facial features. Several features have been described in patients with SCN4, including triangular or round face, full cheeks, midface hypoplasia, malar flattening, frontal bossing, broad forehead, deep-seated eyes, depressed nasal bridge, high-arched palate, tented mouth, prominent lips, prognathism, or retrognathia. We report the facial features of nine patients diagnosed with SNC4. Consistent findings among our patients included high hairline, depressed nose, midfacial hypoplasia, high-arched palate, and full lips. Discrete palpebral edema is present in all our patients. Interestingly, three of our patients presented with ptosis. Our findings align with previous reports, concluding that patients with G6PC3 deficiency exhibit characteristic facial dysmorphisms.