Case#: Spiegel Patient V-2 (proband not designated, so was chosen), female, 7yo at report, Arab Muslin origin
DiseaseAssertion: Infantile Cerebellar-Retinal Degeneration
FamilyInfo: All eight individuals were homozygous for the mutation; ten parents and one of the healthy sibs were heterozygous, and three healthy sibs were homozygous for the normal allele. 3 additional affected individuals are deceased, so it is possible that they were not genotyped and that may be the reason for the discrepancy in the count.
CasePresentingHPOs: HP:0000648, HP:0000639, HP:0012736, HP:0001252, HP:0001251, HP:0002194, HP:0100543, HP:0007359, HP:0002197, HP:0000556, HP:0002120, HP:0001272, HP:0033725, HP:0002500, HP:0001284, HP:0000407
CaseHPOFreeText: birth weight= 2,700 g (10th centile); birth head circumference= 35 cm (50th centile); initial manifestations: hypotonia and ataxia at 2 months; current weight= 11 kg (−5 SD); current head circumference= 46.5 cm (−3.5 SD); current motor skills= does not roll; current cognitive skills= smile, recognize family; focal and generalized seizures; severe retinal dystrophy dx at 1yo; mild cortical atrophy on MR scan at 3mo; severe cerebellar atrophy, moderate cortical atrophy (frontal and temporal), thin corpus callosum, abnormal white matter signal last MR scan at 4 yo; moderate sensorineural hearing loss
CaseNotHPOs:
CaseNotHPOFreeText:
GenotypingMethod: homozygosity mapping, WES
PreviouslyPublished: n/a
Variant: c.336C>G in ACO2 [MIM 100850] (NM_001098.2), which causes p.Ser112Arg (NP_001089.1). homozygous
ClinVar: 29584
FunctionalEvidence: Specific aconitase activity in the individuals' lymphoblasts was severely reduced. Under restrictive conditions, the mutant human ACO2 failed to complement a yeast ACO1 deletion strain, whereas the wild-type human ACO2 succeeded,
AdditionalInfo: 2 "unrelated" families reported, but "Affected individuals of both unrelated clans shared a similar homozygous haplotype, indicating that Ser112Arg is a founder mutation in this population" so will count the segregations as one family
SupplementalData: n/a