Table 2.

Combined at-risk couple rate and affected pregnancies expected across and within racial/ethnic groups by 1 of the 274 disorders.

	At-risk couple rate (%)	Affected pregnancies rate (%)a
General population random coupling	1/44 (2.28)	1/175 (0.58)
Racial/ethnic group
Caucasian	1/32 (3.16)	1/108 (0.93)
Hispanic	1/59 (1.70)	1/192 (0.52)
African American	1/23 (4.42)	1/84 (1.19)
East Asian	1/35 (2.88)	1/128 (0.78)
South East Asian	1/34 (2.96)	1/123 (0.81)
Ashkenazi Jewish	1/17 (5.96)	1/55 (1.81)

^aFor α-thalassemia, individuals with the genotype α-/αα (silent carriers) were excluded. Those with αα/--, α-/α- and α-/-- genotypes were included in calculating the carrier frequency. Inclusion of the α-/α- genotype may have overestimated the combined projected affected pregnancy rate.