Johnson-McMillin syndrome: report of a new case with novel features.

BACKGROUND: Johnson-McMillin syndrome (JMS) is a rare neuroectodermal disorder characterized by alopecia, ear malformations, conductive hearing loss, anosmia/hyposmia, and hypogonadotropic hypogonadism. It is inherited in an autosomal dominant manner; however, the causative gene has not yet been identified. CASE: Herein we report a patient with this condition who exhibits many of the features previously described, including alopecia, malformed auricles, conductive hearing loss, facial asymmetry, and developmental delays. Interestingly, she also has features that have not yet been reported, such as preauricular pits and tags, broad depressions at the lateral aspects of the eyes, and an abnormal left lower eyelid. CONCLUSIONS: In addition to demonstrating a pattern of anomalies consistent with JMS, this patient has several unique features. This phenotype supports the involvement of the branchial arches in the embryologic basis of this condition.

A report of three patients with an interstitial deletion of chromosome 15q24.

Partial monosomy of the q2 region of chromosome 15 has been infrequently reported. Moreover, interstitial deletions involving 15q22-q24 have been described in only nine patients to date. The phenotype of these reported individuals is subject to the extent of the deletion but typically includes altered muscle tone and significant developmental delays. In addition, eye abnormalities, such as strabismus, microphthalmia, or colobomas, ear abnormalities including cleft earlobe and preauricular tags, and urogenital defects are common features. Congenital heart defects, diaphragmatic hernia, abnormalities of the central nervous system, and skeletal anomalies have been reported but appear to be less frequent clinical manifestations. In this report, we describe three new patients with interstitial deletions involving 15q24, two with cryptic deletions identified by fluorescence in situ hybridization (FISH) with a probe for the PML gene and one with a cytogenetically visible deletion of 15q22.3-q24. The clinical presentation of these individuals is similar to those previously described and includes global developmental delays, hypotonia, and genital abnormalities in the males. The identification of these three cases demonstrates that the above clinical features are associated with a new cytogenetic deletion syndrome. Furthermore, we suggest that FISH analysis with a probe for the PML gene be performed in patients with these physical findings.

Genetic defects in the development and function of the anterior pituitary gland.

Genetic defects affecting the hypothalamic-pituitary-target organ axes can cause a variety of diseases involving restricted or broad disruptions of human development and physiology. At the level of the anterior pituitary gland, mutations in the genes encoding key transcription factors, hypothalamic releasing and inhibiting hormone receptors, and the pituitary hormones themselves, can all result in the loss of action of one or more of the specialized hormone-secreting cell types. This article focuses on the effects of inherited and sporadic mutations on the development and function of the anterior pituitary. Mutations in the genes encoding the HESX1, PITX2, LHX3, LHX4, PROP1, PIT1, SF1, and TPIT developmental transcription factors are associated with combined pituitary hormone deficiency diseases. By contrast, deleterious alterations in the genes that encode hypothalamic releasing hormone receptors or pituitary hormones, such as the growth hormone releasing hormone receptor or growth hormone genes, usually result in phenotypes that reflect specific defects in the hormone-secreting capacities of individual anterior pituitary cell types.