Severe congenital neutropenia due to G6PC3 deficiency: early and delayed phenotype in two patients with two novel mutations.
Severe Congenital Neutropenia type 4 (SCN4, OMIM 612541) is a rare autosomal recessive disease due to mutations in the G6PC3 gene. The phenotype comprises neutropenia of variable severity and other anomalies including congenital heart defects, prominent superficial veins, uro-genital anomalies, facial dysmorphism, growth and developmental delay and intermittent thrombocytopenia. In some patients, SCN represents the only manifestation of the disease. Variable findings have been reported at bone marrow examination ranging from a maturation arrest at the myelocyte/promyelocyte stage (either in a hypocellular or hypercellular context) to myelokathexis. Here we report two patients harbouring two novel mutations in the G6PC3 gene, including the first Italian patient even described. Both the patients share profound neutropenia with severe infections early in life; in one case non-hematopoietic stigmata of the syndrome, including evident facial dysmorphism and vascular anomalies, appeared gradually over time, prominently in the second decade. Therefore, G6PC3 defects should be considered in any case of congenital, unexplained neutropenia regardless of the clinical phenotype. Both patients are on G-CSF treatment with no evidence of malignant evolution. Even if G6PC3 deficiency seems not to have a propensity towards malignancy, a careful evaluation is warranted.
Pediatric Onco-haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy. luciadora.notarangelo@spedalicivili.brescia.it.
Lucia Dora
LD
Notarangelo
Department of Pathology, Laboratory of Genetic Disorders of Childhood, A. Nocivelli Institute for Molecular Medicine, Spedali Civili, Brescia, Italy. gianfranco.savoldi@spedalicivili.brescia.it.
Gianfranco
G
Savoldi
Pediatric Onco-haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy. saracav74@gmail.com.
Sara
S
Cavagnini
Pediatric Onco-haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy. veronicabennato@yahoo.it.
Veronica
V
Bennato
U.O. di Pediatria, Ospedale Valduce, Como, Italy. sabr74@yahoo.it.
Sabrina
S
Vasile
Pediatrics Clinic, Spedali Civili of Brescia, Brescia, Italy. genauxo@gmail.com.
Alba
A
Pilotta
Department of Clinical and Experimental Science, Pediatrics Clinic and Institute of Molecular Medicine "A. Nocivelli", University of Brescia and Spedali Civili of Brescia, Brescia, Italy. plebani@med.unibs.it.
Alessandro
A
Plebani
Pediatric Onco-haematology and BMT Unit, Children's Hospital, Spedali Civili of Brescia, Brescia, Italy. fulvio.porta@gmail.com.
Fulvio
F
Porta
D002675:Child, Preschool; D000080984:Congenital Bone Marrow Failure Syndromes; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D005260:Female; D005952:Glucose-6-Phosphatase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D009503:Neutropenia / Q000151:congenital* / Q000235:genetics / Q000378:metabolism; D010375:Pedigree; D010641:Phenotype; D013997:Time Factors; D055815:Young Adult
D004247:DNA; D005952:Glucose-6-Phosphatase; C492193:G6PC3 protein, human