We present five patients with alpha-L-iduronidase deficiency who do not have the typical Hurler or Scheie phenotypes; they are compared to 28 similarly atypical cases from the literature. Phenotypic differences are pointed out and intrafamilial similarities stressed. Among the various possible explanations for this situation, the existence of genetic compounds seems acceptable for some of the cases, but others seem to be caused by different mutations. The elucidation of these alternative possibilities from recent biochemical research is discussed.

SOX2 is an early developmental transcription factor and marker of stem cells that has recently been implicated in the development of the pituitary gland. Heterozygous SOX2 mutations have been described in patients with hypopituitarism and severe ocular abnormalities. In the majority of published cases, the pituitary gland is either small or normal in size. Here, we report two unrelated patients with SOX2 haploinsufficiency (a heterozygous gene deletion and a novel c.143TC>AA/p.F48X mutation) who developed nonprogressive pituitary tumors of early onset, suggesting a congenital etiology. The truncating mutation resulted in significant loss of function and impaired nuclear localization of the mutant protein, in addition to a failure to repress β-catenin transcriptional activity in vitro. This is the first indication that SOX2 haploinsufficiency is implicated in the generation of pituitary tumors with distinct clinical characteristics, possibly mediated via its effects on the Wnt signaling pathway. 32:1376–1380, 2011. ©2011 Wiley Periodicals, Inc.

Metatropic dysplasia is a neonatally manifest entity that is characterized clinically by a rapidly progressing kyphoscoliosis leading to severe shortening of the originally long trunk ("metatropism"). Major radiographic features include flattening and defective ossification of the vertebral bodies, a narrow thorax and a marked hypoplasia of the basilar portions of the ilia with crescent-shaped iliac crests. There is some evidence of genetic heterogeneity. From five personal observations and from a review of the literature we conclude that metatropic dysplasia comprises at least three genetic entities: (1) a nonlethal type with autosomal recessive transmission; (2) a nonlethal dominant type and (3) a lethal type with death before or shortly after birth and possibly autosomal recessive inheritance. A careful clinical and radiologic analysis permits their classification and differentiation from similar, not yet well-delineated disorders. Attention is also drawn to the possibility of atlanto-axial instability in metatropic dysplasia which may cause severe neurologic defects.

A four generation family with postaxial Polydactyly of hands and feet and dental anomalies is reported. Lower and upper incisors were abnormal in shape and number. Additional findings were prominent ear anthelices, hypoplastic and dysplastic nails and mild shortness of stature. Inheritance was dominant with variable expression. It is proposed that the family presents the syndrome of acrofacial dysostosis described by Weyers in 1952. To differentiate it from other acrofacial dysostoses, we suggest naming the condition acrodental dysostosis.

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