Oliver-McFarlane syndrome (OMS) is an extremely rare autosomal recessive disorder primarily characterized by the triad of trichomegaly, congenital hypopituitarism, and chorioretinal degeneration. This study aims to report the clinical and genetic characteristics of the first identified Chinese sibling pair with OMS and to expand the known phenotypic spectrum by documenting a novel clinical feature. We report two Chinese siblings with OMS harboring identical compound heterozygous PNPLA6 variants: c.2990C>T (p.Ser997Leu) and c.3367G>A (p.Gly1123Arg). Both presented with growth hormone deficiency (GHD), short stature, retinitis pigmentosa, and characteristic hair anomalies. Notably, the elder brother exhibited intellectual disability and secondary adrenocortical insufficiency - a feature not previously documented in OMS. In contrast, the younger sister had normal adrenal function and higher cognitive levels. Both patients showed a significant positive growth response to recombinant human growth hormone (rhGH) therapy. This study expands the phenotypic spectrum of PNPLA6-associated OMS to include adrenocortical insufficiency and highlights significant intrafamilial variability.

Oliver-McFarlane syndrome (OMCS) is a rare autosomal recessive disorder characterized by trichomegaly, severe chorioretinal dystrophy, and multiple pituitary hormone deficiencies. Its marked genetic and clinical heterogeneity presents significant challenges for definitive diagnosis. In this study, we initially evaluated a proband clinically diagnosed with OMCS, followed by genetic analysis using whole-exome sequencing (WES). Candidate pathogenic variants were validated via Sanger sequencing and familial co-segregation analysis. WES identified compound heterozygous variants in the PNPLA6 gene: a known missense variant (c.3241G>A, p.Gly1081Arg) and a novel missense variant (c.3461G>A, p.Arg1154His). Over a 13-year follow-up, multisystem involvement was observed, including progressive retinochoroidopathy, trichomegaly, growth retardation, and intellectual disability. Disease progression was evident, with severe exacerbation of retinochoroidopathy accompanied by newly developed pituitary hormone deficiencies and absent secondary sexual characteristics. Our findings expand the pathogenic variant spectrum and clinical phenotypic landscape of OMCS. Given the early onset and progressive nature of retinal involvement, we propose that early intervention targeting the preservation of retinal pigment epithelium (RPE) and photoreceptor function may be clinically beneficial.

Oliver-McFarlane syndrome (OMCS) is an extremely rare congenital disorder that presents with hypogonadotropic hypogonadism, long eyelashes and eyebrows, pigmentary retinopathy, peripheral nerve axon neuropathy and other associated features. It is currently known that OMCS is linked to variants in the patatin-like phospholipase domain containing 6 (PNPLA6) gene, but the specific pathogenic mechanism is still unclear. We performed Whole exome sequencing (WES) on the proband and his parents, followed by validation of the findings through Sanger sequencing and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) analysis. Sanger sequencing identified two compound heterozygous variants in the PNPLA6 (NM_006702.5) gene in the proband: c.3184G>A (p.Val1062Met) and c.2704-18C>G. According to the ACMG guidelines, the c.3184G>A variant is classified as likely pathogenic, while the c.2704-18C>G variant is discovered for the first time. Segregation analysis further revealed that the c.3184G>A variant was inherited from the father, whereas the c.2704-18C>G variant was derived from the mother-consistent with an autosomal recessive inheritance pattern. RT-PCR detected that the c.2704-18C>G variant caused a 29bp deletion upstream of exon 26, resulting in a splice site mutation (p.His902Alafs108). We report a case from China of PNPLA6 gene variants leading to Oliver-McFarlane syndrome, with the patient exhibiting typical characteristics of OMCS. Our findings further substantiate the pathogenicity of PNPLA6 gene variation in OMCS, broadening the established genotypic spectrum of the PNPLA6 gene. These findings enhance the understanding of its pathogenesis and offer perspectives for clinical diagnosis and management.

Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and retinal pigment epithelial atrophy, leading to severe visual impairment or blindness. RP can be classified as nonsyndromic or syndromic with complex clinical phenotypes. Three unrelated Polish probands affected with retinitis pigmentosa coexisting with cerebellar ataxia were recruited for this study. Clinical heterogeneity and delayed appearance of typical disease symptoms significantly prolonged the patients' diagnostic process. Therefore, many clinical and genetic tests have been performed in the past. Here, we provide detailed clinical and genetic analysis results of the patients. Whole-exome sequencing (WES) and targeted NGS analysis allow the identification of four novel and two previously reported variants in the following genes: ABHD12, FLVCR1, and PNPLA6. The use of next-generation sequencing (NGS) methods finally allowed for confirmation of the clinical diagnosis. Ultra-rare diseases such as PHARC, PCARP, and Oliver-McFarlane syndromes were diagnosed in patients, respectively. Our findings confirmed the importance of the application of next-generation sequencing methods, especially in ultra-rare genetic disorders with overlapping features.

Biallelic pathogenic variants in the PNPLA6 gene cause a broad spectrum of disorders leading to gait disturbance, visual impairment, anterior hypopituitarism and hair anomalies. PNPLA6 encodes neuropathy target esterase (NTE), yet the role of NTE dysfunction on affected tissues in the large spectrum of associated disease remains unclear. We present a systematic evidence-based review of a novel cohort of 23 new patients along with 95 reported individuals with PNPLA6 variants that implicate missense variants as a driver of disease pathogenesis. Measuring esterase activity of 46 disease-associated and 20 common variants observed across PNPLA6-associated clinical diagnoses unambiguously reclassified 36 variants as pathogenic and 10 variants as likely pathogenic, establishing a robust functional assay for classifying PNPLA6 variants of unknown significance. Estimating the overall NTE activity of affected individuals revealed a striking inverse relationship between NTE activity and the presence of retinopathy and endocrinopathy. This phenomenon was recaptured in vivo in an allelic mouse series, where a similar NTE threshold for retinopathy exists. Thus, PNPLA6 disorders, previously considered allelic, are a continuous spectrum of pleiotropic phenotypes defined by an NTE genotype:activity:phenotype relationship. This relationship, and the generation of a preclinical animal model, pave the way for therapeutic trials, using NTE as a biomarker.