TABLE I. Family structures for the 72 families with leprosy cases collected from Belém, state of Pará, Brazil.

Family structure	Leprosy per se (n)	Leprosy LL sub-type (n)	Leprosy TT sub-type (n)
Families	72	72	72
Nuclear families	87	56a	48a
with 1 affected sib	19	27	22
with 2 affected sibs	50	25	17
with 3 affected sibs	7	3	7
with 4 affected sibs	5	1	1
with 5 affected sibs	5	0	0
with 6 affected sibs	0	0	1
with 7 affected sibs	1	0	0
Affected offspring	192	90	87
Affected parents	41	25	10
Total affected individualsb	208c	109	93
Total individuals	372	372	372

a : 17 nuclear families contain both lepromatous (LL) and tuberculoid (TT) affected individuals, therefore number of LL + TT nuclear families do not add up to leprosy per se ; b : due to pedigree structure some individuals are classed as both sibs and parents in different nuclear families, therefore the total number of affected is not the sibs + parents; c : six leprosy per se individuals not classified as LL or TT, therefore numbers of affected children and parents for LL + TT do not add up to leprosy per se . Nuclear families with a single affected offspring were always part of an extended multicase pedigree.