Table 1.

Sequence of preproinsulin and site of MIDY mutations

	MIDY mutations		Ages of onset	Original diagnosis	References
	Nomenclature by peptide chain	Nomenclature by preproinsulin a.a.
Signal Peptide	R(SP6)C or H	R6C or H	15-65yr1	MODY1	50,56,60
	A(SP23)S	A23S	6 yr	Type 1	66
	A(SP24)D	A24D	most <6 mo2	Neonatal DM2	49,50,62
Insulin B Chain	H(B5)D	H29D	<6 mo	Neonatal DM	50
	L(B6)M. V. or P	L30M, V or P	<6 mo or 17-38 yr3	Neonatal DM or MODY3	53,60
	G(B8)S or R	G32S or R	most <6 mo4	Neonatal DM or Type 14	49-50,54,66
	L(B11)P	L35P	<6 mo	Neonatal DM	50,53
	LY(B15,16)H	L39Y delinsH	<6 mo	Neonatal DM	53
	C(B19)G	C43G	most <6 mo5	Neonatal DM5	49-50
	R(B22)Q	R46Q	17-24 yr	MODY	51,56
	G(B23)V	G47V	<6 mo	Neonatal DM	49-50
	F(B24)C	F48C	<6 mo	Neonatal DM	49-50
B-C junction	R(Cpep -2)C	R55C	<6 mo or 8-37 yr	Type 1 or MODY	51,60
C-Peptide	G(Cpep28)R	G84R	<6 mo	Neonatal DM	50
C-A junction	R(Cpep+2)C	R89C	most <6 mo6	Neonatal DM6	49-54
Insulin A Chain	G(A1)C	G90C	<6 mo	Neonatal DM	49-50
	C(A6)Y	C95Y	<6 mo	Neonatal DM	53
	C(A7)Y or S	C36Y or S	<6 mo	Neonatal DM	49-50,62,55
	S(A12)C	S101C	<6 mo	Neonatal DM	50
	Y(A14)C	Y103C	<6 mo	Neonatal DM	14
	Y(A19)C or Stop	YlOSC or stop	<6 mo	Neonatal DM	49-50,53

¹One carrier of R(SP6)H, age 20, did not have DM (56,60).

²Age of onset 5 wk - 7 y in 3 members of the same family (50)

³Proband’s mother, age 68, carries mutation without DM (60)

⁴Age of onset 5 mo - 22 y in 4 members of the same family(50)

⁵Proband’s father developed diet-controlled type 2 DM beginning at age 30 (49)

⁶Three family members developed DM age 2 - 4 y (51).

^*The native SP23 of chimpanzee preproinsulin is Ser. In the cartoon on the right, the normal position of Cys residues is overlaid in pink; disulfide pairs shown with red lines

MIDY mutation sites overlaid in green.