Genitourinary malformations as a feature of the Pallister-Hall syndrome

Pallister-Hall syndrome, GLI3, and kidney malformation

Pallister-Hall syndrome (PHS) is a rare autosomal dominant disease diagnosed by the presence of hypothalamic hamartoma, mesoaxial polydactyly and a truncating variant in the middle third of the GLI-Kruppel family member 3 (GLI3) gene. PHS may also include a wide range of clinical phenotypes affecting multiple organ systems including congenital anomalies of the kidney and urinary tract (CAKUT). The observed clinical phenotypes are consistent with the essential role of GLI3, a transcriptional effector in the hedgehog (Hh) signaling pathway, in organogenesis. However, the mechanisms by which truncation of GLI3 in PHS results in such a variety of clinical phenotypes with variable severity, even within the same organ, remain unclear. In this study we focus on presentation of CAKUT in PHS. A systematic analysis of reported PHS patients (n = 78) revealed a prevalence of 26.9% (21/78) of CAKUT. Hypoplasia (± dysplasia) and agenesis were the two main types of CAKUT; bilateral and unilateral CAKUT were reported with equal frequency. Examination of clinical phenotypes with CAKUT revealed a significant association between CAKUT and craniofacial defects, bifid epiglottis and a Disorder of Sex Development, specifically affecting external genitalia. Lastly, we determined that PHS patients with CAKUT predominately had substitution type variants (as opposed to deletion type variants in non-CAKUT PHS patients) in the middle third of the GLI3 gene. These results provide a foundation for future work aimed at uncovering the molecular mechanisms by which variant GLI3 result in the wide range and severity of clinical features observed in PHS.

Pallister-Hall syndrome with orofacial narrowing and tethered cord: a case report

Background

Pallister–Hall syndrome is a rare, autosomal dominant, genetic disorder characterized by different congenital abnormalities: hypothalamic hamartoblastoma, bifid or shortened epiglottis, polydactyly, renal anomalies, and imperforate anus.

Case presentation

In this case report, we describe the case of a 13-year-old Lebanese-Armenian boy born with Pallister–Hall syndrome showing newly associated manifestations (orofacial narrowing and tethered cord), and currently showing a spontaneous puberty with normal growth pattern following management with growth hormones.

Conclusions

This case report shows a practical approach to this very rare syndrome, mainly with testosterone and growth hormones, and its follow-up in the long term. Being familiar with such cases may allow improvement of our knowledge for better management in the future.

GLI3-related polydactyly: a review

GLI3 mutations are known to be associated with nine syndromes/conditions in which polydactyly is a feature. In this review, the embryology, pathogenesis, and animal models of GLI3-related polydactyly are discussed first. This is followed by a detailed review of the genotype-phenotype correlations. Based on our review of the literature and our clinical experiences, we recommend viewing GLI3-related syndromes/conditions as four separate entities; each characterized by a specific pattern of polydactyly. These four entities are: the preaxial polydactyly type IV-Greig-acrocallosal spectrum, postaxial polydactyly types A/B, Pallister-Hall syndrome (PHS), and oral-facial-digital overlap syndrome. We also provide illustrative clinical examples from our practice including a family with a novel GLI3 mutation causing PHS. The review also introduces the term 'Forme Fruste' preaxial polydactyly and gives several conclusions/recommendations including the recommendation to revise the current criteria for the clinical diagnosis of PHS.

Cochlear abnormality in a case of Pallister-Hall syndrome

Pallister-Hall syndrome (PHS) is a rare condition characterised by anomalies including hypothalamic hamartoma, bifid epiglottis and postaxial polydactyly. Hearing loss has been recognised in this condition. Cochlear abnormalities have been described in mouse models of PHS, but there are no reports of similar findings in humans to date. This report describes a case of PHS with bilateral cochlear hypoplasia as seen on MRI.

Genital abnormalities in Pallister-Hall syndrome: Report of two patients and review of the literature

We describe two patients with Pallister-Hall syndrome (PHS) with genital abnormalities: a female with hydrometrocolpos secondary to vaginal atresia and a male with micropenis, hypoplastic scrotum, and bilateral cryptorchidism. Nonsense mutations in GLI3 were identified in both patients. Clinical and molecular findings of 12 previously reported patients who had GLI3 mutations and genital abnormalities were reviewed. Genital features in the male patients included hypospadias, micropenis, and bifid or hypoplastic scrotum, whereas all the females had hydrometrocolpos and/or vaginal atresia. No hotspot for GLI3 mutations has been found. The urogenital and anorectal abnormalities associated with PHS might be related to dysregulation of SHH signaling caused by GLI3 mutations rather than hormonal aberrations. We recommend that clinical investigations of genital abnormalities are considered in patients with PHS, even those without hypopituitarism.

Hydrometrocolpos, postaxial polydactyly, and hypothalamic hamartoma in a patient with confirmed Pallister-Hall syndrome: a clinical overlap with McKusick-Kaufman syndrome

We present a preterm-born girl with polydactyly of both hands and massive hydrometrocolpos, the latter due to vaginal atresia. This association led initially to the diagnosis of McKusick-Kaufman syndrome (MKKS). However, additional features, including characteristic radiographic findings of the hands and a large hypothalamic tumour, presumably a hamartoma, favoured the diagnosis of Pallister-Hall syndrome (PHS), which was then genetically confirmed by detection of a GLI3 mutation (Q717X). This is the second genetically confirmed case revealing the previously described association of PHS with hydrometrocolpos due to vaginal atresia as a clinical overlap with MKKS.

Genetic syndromes and prenatally detected renal anomalies

Renal anomalies are frequently detected on the routine second trimester scan offered to all pregnant women in the UK. These anomalies may be isolated but can also be associated with other congenital anomalies. Many combinations of ultrasound scan findings constitute recognised genetic entities. Knowledge of these conditions is essential for adequate management of the pregnancy and subsequent balanced parental counselling. This short review discusses the common genetic syndromes associated with the renal abnormalities identified on the antenatal ultrasound scan, and also provides an overview of renal symptoms in chromosome imbalances and after teratogenic influences.