"Shifted" threshold may explain diversity of cardiovascular malformations in multiple congenital abnormalities syndromes: 3C (Ritscher-Schinzel) syndrome as an example

A rare case of 3C disease: Ritscher-Schinzel syndrome presenting with recurrent talipes equinovarus

INTRODUCTION

Club foot (CF) is characterized by multiple deformities such as varus, adductus and internal rotation of the forefoot. It is well-known and a frequent congenital disorder. CF can concurrently be seen with several diseases but it can rarely manifest as a component of any other syndrome. Ritscher-Schinzel syndrome, or cranio-cerebello-cardiac syndrome, is rarely seen and has autosomal recessive inheritance. It is characterized by cranio-facial, cerebellar and cardiac abnormalities. We report a case diagnosed as Ritscher-Schinzel syndrome concurrent with persistent CF.

PRESENTATION OF CASE

A two-year-old boy with persistent CF and concurrent congenital hip dysplasia. Despite successful serial casting and subsequent achilloplasty a clinical relapse was observed in our patient. After a detailed phenotypic evaluation, genetical tests and imaging technique the patient was diagnosed 3C Ritscher-Schinzel syndrome.

DISCUSSION

A comprehensive literature review did not show any reports about concurrent hip dysplasia and clubfoot in Ritscher-Schinzel syndrome. We report that CF may be associated with rare genetical abnormalities.

CONCLUSION

With this report we would like to raise awareness about the possible association of persistent CF with this rare genetical disorder, Ritscher-Schinzel syndrome. It should be included in differential diagnosis of patients with persistent CF.

Radiographic characterization of the hands in Ritscher-Schinzel/3-C syndrome

Abstract

Ritscher-Schinzel Syndrome (RSS) is a clinically variable, autosomal recessive disorder, involving cardiac, cerebellar and craniofacial abnormalities. Numerous reports describe hand changes in RSS patients; however, a detailed characterization of the hands has not previously been performed.

Objective

The purpose of this study was to identify whether specific radiographic hand changes were characteristic of RSS and could serve as a diagnostic tool.

Materials and methods

We performed a detailed radiographic hand characterization of 8 RSS patients. The patient population consisted of 5 males and 3 females from ages one month to 26 years, 7 months. The hands were characterized using metacarpophalangeal pattern (MCPP) profiles, carpal height and bone age analyses and assessment of bone morphology.

Results

There was generalized brachydactyly with the second ray being the most severely affected. There was significant shortening of the first metacarpal and the fifth distal phalanx. The MCPP profile generated showed a consistent wavy pattern with average Z-scores ranging from -0.15 (4^th proximal phalanx) to -2.13 (1^st metacarpal) and 0.53 (4^th middle phalanx) to -1.73 (2^nd proximal phalanx) for the left and right hands, respectively. Six of eight patients showed a decreased carpal height. Bone age was within normal limits for all patients. Our study population showed consistent radiographic changes including: overtubulation of the bones (especially metacarpals 2-4), prominent tufts of the distal phalanges and a hypoplastic fifth distal phalanx.

Conclusion

The hand findings identified in this study can provide helpful diagnostic tools to clinicians when the diagnosis of RSS is being considered.

Segregation ratio in cranio-cerebello-cardiac syndrome

According to several authors cranio-cerebello-cardiac (3C) syndrome is an autosomal recessive disorder. This opinion was based on pedigree inspection without formal segregation analysis. Recently, the assumption of autosomal recessive inheritance was challenged by the observation of overlapping features with 6p deletions. We therefore performed segregation analysis by means of methods described by Li and Mantel, Davie and Lange on 27 pedigrees selected from literature. The results of all three methods are consistent with autosomal recessive inheritance but their broad confidence intervals leave room for other explanations as well. Reporting of 3C cases without evaluation of 6p copy number should be discouraged from now on.