Holoprosencephaly–polydactyly/pseudotrisomy 13: a presentation of two new cases and a review of the literature

Patients with a combination of holoprosencephaly and polydactyly, but with apparently normal chromosomes, may be clinically diagnosed with holoprosencephaly–polydactyly syndrome (HPS), also termed pseudotrisomy 13. However, the criteria for HPS have been controversial since the advent of the diagnostic term, and a clear understanding of the condition lacks definitive delineation. We review the historical and current perspectives on the condition and analyze findings in 40 patients with apparent HPS, including cases from the literature and two previously unreported patients. Overall, our analysis suggests previously unrecognized trends in patients diagnosed with HPS. Specifically, there appears to be a higher prevalence of visceral anomalies, most significantly cardiac and genitourinary, but also with increased gastrointestinal, pulmonary, adrenal, skeletal, and renal abnormalities, in patients with HPS. Although these visceral anomalies may not be essential for the identification of HPS, clinicians should be aware of the presence of such characteristics in these patients to optimize management and help establish etiologies

Mutations in ZIC2 in human holoprosencephaly: description of a novel ZIC2 specific phenotype and comprehensive analysis of 157 individuals.

International audienceHPE due to ZIC2 mutations is distinct from that due to mutations in other genes. This may shed light on the mechanisms involved in formation of the forebrain and face and will help direct genetic counselling and diagnostic strategies