Boucher Neuhäuser Syndrome (BNS) is a rare disease with autosomal recessive inheritance defined by the classical triad; early-onset ataxia, hypogonadism and chorioretinal dystrophy. We present two siblings diagnosed with BNS at midlife, identified with homozygous state of a novel PNPLA6 missense mutation. One healthy sibling and the mother were heterozygous carriers of the mutation. The proband presented with the classical triad and the other sibling presented with visual problems at first. The proband was referred to our department by a private Neurologist, in early adulthood, because of hypogonadism, cerebellar ataxia, axonal neuropathy, and chorioretinal dystrophy for further evaluation. The sibling was referred to our department for evaluation, at childhood, due to visual problems. Later, the patient displayed the triad of ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy. The unusual medical history of the two siblings led to further examinations and eventually the diagnosis of the first BNS cases in Cyprus. WES-based ataxia in silico gene panel analysis revealed 15 genetic variants and further filtering analysis revealed the PNPLA6 c.3323G > A variant. Segregation analysis in the family with Sanger sequencing confirmed the PNPLA6 homozygous variant c.3323G > A, p.Arg1108Gln in exon 29. This highlights the importance of considering rare inherited causes of visual loss, spinocerebellar ataxia, or/and HH in a neurology clinic and the significant role of genetic sequencing in the diagnostic process.

Boucher-Neuhäuser syndrome (BNHS) is characterized by chorioretinal dystrophy, hypogonadotropic hypogonadism, and cerebellar dysfunction and atrophy. The disorder has been associated with biallelic pathogenic variants in the patatin-like phospholipase domain-containing protein 6 (PNPLA6) gene. We present an individual with a clinical diagnosis consistent with BNHS who lacked any PNPLA6 variants but on quartet family exome sequencing had a de novo variant in the hexokinase 1 (HK1) gene (NM_000188.2 [GRCh37/hg19]: g.71139826G>A, c.1240G>A, p.Gly414Arg), suggesting genetic heterogeneity for BNHS. Longitudinal follow-up indicated neurological deterioration, neuropsychiatric symptoms, and progressive cerebellar atrophy. The BNHS phenotype overlaps and expands the known HK1 genotypic and phenotypic spectrum. Individuals with variants in HK1 should undergo evaluation for hypogonadotropic hypogonadism, potentially amenable to treatment.

Boucher-Neuhäuser Syndrome (BNS) is a rare autosomal recessive disorder characterized by hypogonadotropic hypogonadism, spinocerebellar ataxia, and chorioretinal syndrome, and associated with a variant in the PNPLA6 gene. Although many reports have mentioned the presence of cognitive impairment, a neuropsychological assessment of a BNS case has never been published. Here, we provide a detailed description of a young adult patient with BNS who has a homozygous pathogenic variant in the PNPLA6 gene. A 21-year-old man with progressive ataxia and a history of hypogonadotropic hypogonadism and chorioretinal dystrophy was diagnosed with BNS. A comprehensive cognitive evaluation was performed, requiring the ad hoc selection and adaption of neuropsychological tests to overcome visual and motor impairments that characterize this syndrome. The patient presented an intact global cognitive profile with selective executive dysfunction and mild verbal reasoning dysfunction. In particular, attentional-inhibitory control, working memory, and set switching were impaired, and inadequate development of conceptual knowledge and abstract reasoning was observed. This is the first report of an explicitly documented comprehensive neuropsychological assessment in a patient with BNS. The battery we composed is an example of a methodology that can be used to conduct a detailed cognitive examination without being penalized for physical impairment.Further studies are needed to define the typical cognitive features that characterize BNS and possibly identify its cognitive phenotype(s).

Purpose: The current study aims to raise awareness of Boucher - Neuhauser syndrome (BNHS) that occurs as a rare phenotype due to biallelic pathogenic variants in the PNPLA6 gene.Methods: Detailed family histories and clinical data were recorded. Whole exome sequencing was performed and co-segregation analysis of the family was done by sanger sequencing. Also, review of 28 molecularly confirmed patients with BNHS from the literature was evaluated.Results: We identified a missense homozygous variant (c.3524 C > G (p.Ser1175Cys)) in the PNPLA6 gene, which explains the phenotype of the patient and neurologic, ophthalmologic, endocrine, and genetic evaluations established a diagnosis of BNHS. Symptoms, ethnicity, clinical and genetic findings of 28 molecularly confirmed patients with BNHS from the literature were also presented.Conclusion: We present the main findings of a Turkish family with BNHS together with detailed clinical and genetic profiles of patients diagnosed as BNHS that have been molecularly confirmed in the literature so far.

To describe the retinal findings in a 25-year-old white woman in whom a diagnosis of Boucher-Neuhäuser Syndrome (BNS) was supported by genetic testing, which identified a missense and novel nonsense mutation in the PNPLA6 gene. Observational case report of a 25-year-old woman who presented with primary amenorrhea, cerebellar ataxia, and mild retinal pigmentary abnormalities. Neurologic, endocrine, and genetic evaluations established a diagnosis of BNS. Clinical examination and multimodal imaging documented focal outer retinal and retinal pigment epithelium changes including bilateral foveal stippling and a circular area of hypopigmentation in the superior macula of the left eye. Optical coherence tomography showed a linear area of outer retinal attenuation superonasal to the fovea and multiple foci of pinpoint outer retinal defects in the temporal macula of the left eye. Humphrey visual field 24-2 testing showed nonspecific defects in both eyes. Full-field electroretinography showed no evidence of a generalized retinal dysfunction. Recognition that the chorioretinal abnormalities occurring in BNS can be rather subtle is essential because the diagnosis of BNS may depend on their detection. To the best of our knowledge, this is the first report in the ophthalmic literature of mild chorioretinal changes in a patient with BNS testing positive for a mutation in the PNPLA6 gene.