Table 1.

Patients and Summary of Clinical Findings in SASD

Disease	Clinical Characterization	Age at Onset	Free Sialic Acidin Urinea	No. of Cases in Study
SD	Hypotonia and ataxia, ocular squint, delayed development, few words, able to walk; IQ 20–30; life span near normal	6–12 mo	12 fold (5–36)	73 Finnish, 15 Swedish,b 2 Englishc
Intermediate “severe Salla”	Severe hypotonia, later ataxia, spasticity; growth delay; no organomegaly; seizures; shortened life span	1–6 mo	15–34 fold	7 Finnish, 1 Dutch,d 1 Italian,e 1 Germanb
ISSD	Intrauterine hydrops, neonatal ascites, enlarged liver; dysmorphic features; failure to thrive; early death (age <2 years)	Intrauterine	102 fold (18–245)	10 Whitef

^aMean of free sialic acid in normal controls: 58±19 nM/mg creatinine (Aula and Gahl, in press).

^bReported by Schleutker et al. (1995b).

^cReported by Robinson et al. (1997).

^dReported by Mancini et al. (1992).

^eReported by Fois et al. (1987).

^fPatients Mc.I., J.G., R.D., D.R., A.Z., and A.B. (Verheijen et al. 1999), S.L., C.J., and C.G. (Schleutker et al. 1995b), and P.M. (Dr. I. Maire, Lyon).