Table 1. Underlying factors for Kagami–Ogata syndrome and upd(14)pat.

	Japanese (n=35)	Non-Japanese (n=18)	Total (n=53)
Underlying causes for KOS
Upd(14)pat	23	14	37
Normal karyotype	20	5	25
Abnormal karyotype	3	9	12
Epimutation	7a	0	7
Microdeletion	5b	4c	9
Underlying mechanisms for upd(14)pat
Normal karyotype
TR/GC	7	0	7
MR/PE	12	2	14
PE	1	2	3
No detailed information	0	1	1
Abnormal karyotype
Robertsonian translocation	2d	3e	5
Isochromosome for 14q	0	5f	5
Unknown/other karyotype	1	1g	2

Abbreviations: GC, gamete complementation; KOS, Kagami–Ogata syndrome; MR, monosomy rescue; PE, postfertilization mitotic error; TR, trisomy rescue; upd(14)pat, paternal uniparental disomy 14.

^aIncluding two hitherto unreported patients.

^bIncluding sibling cases; thus, four microdeletions have been found in five patients.

^cIncluding sibling cases; thus, three microdeletions have been detected in four patients.

^d45,XX,rob(13;14)(q10;q10) (n=1) and 45,XX,rob(14;21)(q10;q10q) (n=1); parental karyotype has not been examined.

^e45,XX,rob(13;14)(q10;q10) (n=3); the same Robertsonian translocations have been found in the fathers of the three patients.

^f45,XX,i(14q) (n=4) and 45,XY,i(14q) (n=1); parental karyotypes are invariably normal in the five patients.

^g46,XX[6]/47,XX,+mar[44]. Although the marker chromosome is derived from chromosome 14, it does not involve the 14q32.2 imprinted region, and full isodisomy for chromosome 14 has been shown by microsatellite analysis.