A diagnostic conundrum: two siblings with features overlapping the Kabuki and Malpuech syndromes. A new MCA syndrome?

Abstract

We report two siblings, a boy and a girl, with a constellation of anomalies that overlap the phenotypes of Kabuki and Malpuech syndromes. Both patients had a facial appearance suggestive of Kabuki syndrome, sagittal vertebral clefts, and short fifth fingers. In addition, the girl had brachydactyly of the index finger, and the boy, cleft lip and palate, mild postnatal growth deficiency, coarctation of the aorta, ventricular septal defect, patent ductus arteriosus, and a caudal appendage. The fact that this pattern of anomaly occurred in siblings, together with the presence of sparse eyebrows medially, rather than laterally, in both patients and a caudal appendage in the boy, militates against the diagnosis of Kabuki syndrome. Furthermore, the presence of a caudal appendage in a child with cleft lip and cleft palate and renal abnormalities is suggestive of Malpuech syndrome. The normal growth pattern and psychomotor development observed in both children, however, is inconsistent with this diagnosis, although they may represent a milder end of the phenotypic spectrum for Malpuech syndrome. Alternatively, we conclude that the condition may represent a distinct multiple congenital anomaly (MCA) syndrome. The occurrence of a pattern of MCA in two siblings with phenotypically normal parents and normal cytogenetic studies, including high-resolution banding and subtelomeric probes, points toward an autosomal recessive mode of inheritance. However, germinal mosaicism and other types of non-traditional inheritance, such as a defect in genomic imprinting or uniparental disomy, should also be considered.