Neuroimaging appearance of hypothalamic hamartomas in monozygotic twins with Pallister-Hall syndrome: case report and review of the literature.

BACKGROUND: Pallister-Hall syndrome (OMIM #146510) is a rare autosomal dominant condition caused by a mutation in the GLI3 gene. The cardinal feature of Pallister-Hall syndrome is the presence of hypothalamic hamartomas, which may manifest with seizures, panhypopituitarism and visual impairment. In Pallister-Hall syndrome, dysplastic histogenetic processes responsible for hypothalamic hamartomas are thought to disrupt early craniofacial development. The clinical presentation of Pallister-Hall syndrome may include: characteristic facies (low-set and posteriorly angulated ears, short nose with flat nasal bridge), cleft palate and uvula, bifid epiglottis and laryngotracheal cleft, limb anomalies (e.g., polysyndactyly, short limbs and nail dysplasia), anal atresia, genitourinary abnormalities and congenital heart defects. CASE PRESENTATION: We report the case of two monochorionic diamniotic twins diagnosed with Pallister-Hall syndrome during the neonatal period, after the identification of a hypothalamic hamartoma on day 1 by cerebral ultrasound scan, later confirmed by brain magnetic resonance imaging. Cerebral ultrasound and magnetic resonance imaging presentations were identical in both twins. DISCUSSION AND CONCLUSIONS: We review previously published cases (four reports) of hypothalamic hamartomas identified via cerebral ultrasound and compare reported ultrasonographic features. Main differential diagnoses based on cerebral ultrasound findings are discussed. Full description of typical magnetic resonance imaging appearance is also provided. This is the first case reported in the literature of monochorionic diamniotic twins affected by genetically confirmed Pallister-Hall syndrome with identical hypothalamic hamartomas at cerebral ultrasound and magnetic resonance imaging. Moreover, this paper adds to the existing literature on the sonographic appearance of hypothalamic hamartomas. Considering the consistency in hypothalamic hamartomas' sonographic appearance, we support the use of cerebral ultrasound as a first-line neuroimaging modality in case of clinical suspicion of Pallister-Hall syndrome.

A GLI3 variant leading to polydactyly in heterozygotes and Pallister-Hall-like syndrome in a homozygote.

Variants in transcriptional activator Gli Kruppel Family Member 3 (GLI3) have been reported to be associated with several phenotypes including Greig cephalopolysyndactyly syndrome (MIM #175700), Pallister-Hall syndrome (PHS) (MIM #146510), postaxial polydactyly types A1 (PAPA1) and B (PAPB) (MIM #174200), and preaxial polydactyly type 4 (MIM #174700). All these disorders follow an autosomal dominant pattern of inheritance. Hypothalamic hamartomas (MIM 241800) is associated with somatic variants in GLI3. We report a related couple with parents having PAPA1 and PAPB, who had a fetus with a phenotype most compatible with PHS. Molecular analyses demonstrated homozygosity for a pathogenic GLI3 variant (c.1927C > T; p. Arg643*) in the fetus and heterozygosity in the parents. The genetic analysis in this family demonstrates that heterozygosity and homozygosity for the same GLI3 variant can cause a different phenotype. Furthermore, the occurrence of Pallister-Hall-like syndrome in a homozygous patient should be taken into account in genetic counseling of families with PAPA1/PAPB.

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.

Fetal MRI of a hypothalamic hamartoma in Pallister-Hall syndrome.

Fetal magnetic resonance imaging is increasingly being used as an adjunct to ultrasound. It allows for better visualization of in utero brain development and intracranial abnormalities (especially cerebral malformations). Hypothalamic hamartoma is a nonneoplastic malformation resembling normal hypothalamic tissue both histologically and on magnetic resonance imaging. Although it is rare, this entity is important to recognize for appropriate management and genetic counseling. We describe a unique patient in whom magnetic resonance imaging of the fetal brain allowed a prenatal diagnosis of Pallister-Hall syndrome.

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.

Genitourinary malformations as a feature of the Pallister-Hall syndrome.

Pallister-Hall and McKusick-Kaufman syndromes are developmental disorders with well defined phenotypes, distinct loci and different patterns of inheritance. The clinical features can overlap and may cause diagnostic difficulty, particularly if complex genitourinary malformations are present. A case is presented with features of both syndromes but in which a GLI3 mutation has been identified. A literature review of similar cases is presented and it is proposed that these cases probably represent the Pallister-Hall syndrome. A detailed abdominal and perineal examination should be considered in all female patients with the Pallister-Hall syndrome, looking for associated genitourinary anomalies. Conversely, all girls with features suggestive of McKusick-Kaufman syndrome require neuroimaging to look for features of the Pallister-Hall syndrome. The correct diagnosis is important so that the patient and the family may receive appropriate management. It also allows provision for an accurate recurrence risk.