HAX1 deficiency causes autosomal recessive severe congenital neutropenia (Kostmann disease).
Autosomal recessive severe congenital neutropenia (SCN) constitutes a primary immunodeficiency syndrome associated with increased apoptosis in myeloid cells, yet the underlying genetic defect remains unknown. Using a positional cloning approach and candidate gene evaluation, we identified a recurrent homozygous germline mutation in HAX1 in three pedigrees. After further molecular screening of individuals with SCN, we identified 19 additional affected individuals with homozygous HAX1 mutations, including three belonging to the original pedigree described by Kostmann. HAX1 encodes the mitochondrial protein HAX1, which has been assigned functions in signal transduction and cytoskeletal control. Here, we show that HAX1 is critical for maintaining the inner mitochondrial membrane potential and protecting against apoptosis in myeloid cells. Our findings suggest that HAX1 is a major regulator of myeloid homeostasis and underline the significance of genetic control of apoptosis in neutrophil development.
Klein
Christoph
C
Department of Pediatric Hematology/Oncology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany. klein.christoph@mh-hannover.de
Grudzien
Magda
M
Appaswamy
Giridharan
G
Germeshausen
Manuela
M
Sandrock
Inga
I
Schäffer
Alejandro A
AA
Rathinam
Chozhavendan
C
Boztug
Kaan
K
Schwinzer
Beate
B
Rezaei
Nima
N
Bohn
Georg
G
Melin
Malin
M
Carlsson
Göran
G
Fadeel
Bengt
B
Dahl
Niklas
N
Palmblad
Jan
J
Henter
Jan-Inge
JI
Zeidler
Cornelia
C
Grimbacher
Bodo
B
Welte
Karl
K
D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D000328:Adult; D017209:Apoptosis; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D005260:Female; D005808:Genes, Recessive; D005820:Genetic Testing; D006801:Humans; D007223:Infant; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000235:genetics; D009154:Mutation; D022423:Myeloid Cells / Q000378:metabolism; D009503:Neutropenia / Q000151:congenital* / Q000235:genetics*; D010375:Pedigree; D011506:Proteins / Q000235:genetics*; D013577:Syndrome
D048868:Adaptor Proteins, Signal Transducing; C104759:HAX1 protein, human; D011506:Proteins