Overlapping phenotypes in OFD type II and OFD type VI: report of two cases

Area of Science:

• Genetics
• Medical Genetics
• Syndromology

Background:

• OrofacioDigital (OFD) syndromes encompass a group of rare genetic disorders.
• Mohr syndrome, classified as OFD type II, is an autosomal recessive condition.
• OFD type II shares overlapping features with OFD type VI, Joubert syndrome, and Majewski syndrome.

Observation:

• A review of five patients with OFD identified two exhibiting Y-shaped metacarpals, consistent with Mohr syndrome.
• These patients also presented with specific radiological findings: hypoplastic middle phalanges of index fingers and enlarged metatarsals with accessory phalanges.

Findings:

• The observed radiological anomalies in patients with OFD type II suggest a broader phenotypic spectrum.
• Specific digital anomalies, including Y-shaped metacarpals and hypertrophied metatarsals, are key indicators.

Implications:

• The findings support the hypothesis that Mohr syndrome (OFD type II) and OFD type VI are part of a continuous phenotypic spectrum.
• This continuum may range from milder presentations to severe forms with central nervous system abnormalities.