Table 1.

Characteristic features of different types of CDA

CDA type	I	II	III Familial	III Sporadic	Variants
Inheritance	Autosomal recessive	Autosomal recessive	Dominant	Variable	Autosomal dominant or X linked or recessive
Cases reported	>300	>450	2 families	<20	∼70
BM morphology (light microscopy)	Abnormal chromatin structure, chromatin bridges	Binuclearity, multinuclearity of mature erythroblasts	Giant multinucleated erythroblasts	Giant multinucleated erythroblasts	CDA I–like, CDA II–like, others
BM EM findings	“Spongy” heterochromatin, invagination of cytoplasm into the nucleus	Peripheral cysternae beneath the plasma membrane	Clefts in heterochromatin, autophagic vacuoles, intranuclear cisternae	Various	Various
Mutated gene	CDAN1, C15ORF41	SEC23B	KIF23	Unknown	KLF1, GATA-1, unknown
Associated dysmorphology/organ involvement	Skeleton	Variable, rare	Monoclonal gammopathy, myeloma, angioid streaks	Variable	CNS, others

CNS, central nervous system; EM, electron microscopy.