Objective: Juberg-Hayward syndrome (JHS; MIM 216100) is a rare autosomal recessive malformation syndrome, characterized by cleft lip/palate, microcephaly, ptosis, hypoplasia or aplasia of thumbs, short stature, dislocation of radial head, and fusion of humerus and radius leading to elbow restriction. A homozygous mutation in ESCO2 has recently been reported to cause Juberg-Hayward syndrome. Our objective was to investigate the molecular etiology of Juberg-Hayward syndrome in two affected Lisu tribe brothers.
Materials and methods: Two patients, the unaffected parents, and two unaffected siblings were studied. Clinical and radiographic examination, whole exome sequencing, Sanger sequencing, Western blot analysis, and chromosome testing were performed.
Results: Two affected brothers had characteristic features of Juberg-Hayward syndrome, except for the absence of microcephaly. The elder brother had bilateral cleft lip and palate, short stature, humeroradial synostosis, and simple partial seizure with secondary generalization. The younger brother had unilateral cleft lip and palate, short stature, and dislocation of radial heads. The homozygous (c.1654C > T; p.Arg552Ter) mutation in ESCO2 was identified in both patients. The other unaffected members of the family were heterozygous for the mutation. The presence of humeroradial synostosis and radial head dislocation in the same family is consistent with both being in the same spectrum of forearm malformations. Chromosome testing of the affected patients showed premature centromere separation. Western blot analysis showed reduced amount of truncated protein.
Conclusion: Our findings confirm that a homozygous mutation in ESCO2 is the underlying cause of Juberg-Hayward syndrome. Microcephaly does not appear to be a consistent feature of the syndrome.
Keywords: Cleft lip and palate; Dislocation of radial head; ESCO2; Humeroradial synostosis; Hypoplastic thumb; Interphalangeal inflexibility; Symphalangism.
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