Autosomal-recessive syndrome with alopecia, hypogonadism, progressive extra-pyramidal disorder, white matter disease, sensory neural deafness, diabetes mellitus, and low IGF1

Woodhouse-Sakati syndrome: A review

Neurodegeneration with brain iron accumulation (NBIA) is a rare and inherited spectrum of movement disorders caused by mutations affecting the function of proteins that participate in the homeostasis of tissue metals such as iron or copper and other metabolic pathways, although the precise function of the proteins encoded are not always known. Woodhouse-Sakati Syndrome (WSS) is one of the rarest NBIAs. Patients with WSS are characterized by endocrinological and neurological manifestations and neuroradiological findings. However, diagnostic criteria have not been published yet. This article reviews updates on the genetic, clinical, biological and imaging findings of WSS and provides a practical guide to recognize this extremely rare disorder.

Nine Hereditary Movement Disorders First Described in Asia: Their History and Evolution

Clinical case studies and reporting are important to the discovery of new disorders and the advancement of medical sciences. Both clinicians and basic scientists play equally important roles leading to treatment discoveries for both cures and symptoms. In the field of movement disorders, exceptional observation of patients from clinicians is imperative, not just for phenomenology but also for the variable occurrences of these disorders, along with other signs and symptoms, throughout the day and the disease course. The Movement Disorders in Asia Task Force (TF) was formed to help enhance and promote collaboration and research on movement disorders within the region. As a start, the TF has reviewed the original studies of the movement disorders that were preliminarily described in the region. These include nine disorders that were first described in Asia: Segawa disease, PARK-Parkin, X-linked dystonia-parkinsonism, dentatorubral-pallidoluysian atrophy, Woodhouse-Sakati syndrome, benign adult familial myoclonic epilepsy, Kufor-Rakeb disease, tremulous dystonia associated with mutation of the calmodulin-binding transcription activator 2 gene, and paroxysmal kinesigenic dyskinesia. We hope that the information provided will honor the original researchers and help us learn and understand how earlier neurologists and basic scientists together discovered new disorders and made advances in the field, which impact us all to this day.

Three Siblings With Woodhouse-Sakati Syndrome: A Case Report of A New Saudi Family

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive multi-system genetic disease caused by loss of function mutations in the DCAF17 gene on chromosome 2q31.1. The disease is characterized by gradual neurologic degeneration and polyendocrinopathy, particularly noteworthy for hypogonadism, beginning in early adolescence. Clinical features show wide variability with no clear genotype-phenotype correlation. The pathophysiology of WSS is unclear at present and no specific treatment is available other than hormone replacement which is administered in the course of individualized symptomatic multidisciplinary care. Genetic testing helps in confirming the diagnosis along with genetic counseling of the patient and family members. Here we report multiple cases of WSS in three siblings from a new Saudi Arabia family who were diagnosed with WSS as a consequence of a common founder mutation in the DCAF17 gene with DNA analysis showing a homozygous single nucleotide frameshift deletion (c.436delC) in exon 4 of the gene.

Woodhouse-Sakati Syndrome Presenting With Psychotic Features After Starting Trihexyphenidyl: A Case Report

Woodhouse-Sakati syndrome is a rare, autosomal recessive, multisystemic disorder first identified as a constellation of hypogonadism, mental retardation, diabetes, alopecia, deafness, and electrocardiogram abnormalities. 

We report a case of a 33-year-old woman who was born to consanguineous parents. She is suffering from hypergonadotropic hypogonadism, extrapyramidal symptoms, hypothyroidism, alopecia, and sensorineural hearing loss. Her MRI showed iron depositions in globus pallidus bilaterally. She underwent genetic testing and was diagnosed with Woodhouse-Sakati syndrome. She was started on trihexyphenidyl to treat her extrapyramidal symptoms. A few months later, she started to have psychotic symptoms in the form of auditory hallucinations and delusions of persecution. 

Although she exhibited psychotic symptoms after starting trihexyphenidyl, it is less likely to be causing her symptoms since the symptoms started a few months after taking the medication and she was not on high doses. Thus, it is more likely to be a part of Woodhouse-Sakati syndrome.

Movement Disorders Associated with Hypogonadism

A variety of movement disorders can be associated with hypogonadism. Identification of this association may aid in guiding workup and reaching an accurate diagnosis. We conducted a comprehensive and structured search to identify the most common movement disorders associated with hypogonadism. Only Case Reports and Case Series articles were included. Ataxia was the most common movement disorder associated with hypogonadism, including entities such as Gordon-Holmes syndrome, Boucher-Neuhäuser, Marinesco-Sjögren and Perrault syndrome. Tremor was also commonly described, particularly with aneuploidies such as Klinefelter syndrome and Jacob's syndrome. Other rare conditions including mitochondrial disorders and Woodhouse-Sakati syndrome are associated with dystonia and parkinsonism and either hypo or hypergonadotropic hypogonadism. We also highlight those entities where a combination of movement disorders is present. Hypogonadism may be more commonly associated with movement disorders than previously appreciated. It is important for the clinician to be aware of this association, as well as accompanying symptoms in order to reach a precise diagnosis.

Expanding on the phenotypic spectrum of Woodhouse-Sakati syndrome due to founder pathogenic variant in DCAF17: Report of 58 additional patients from Qatar and literature review

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive neuroendocrine and ectodermal disorder caused by variants in the DCAF17 gene. In Qatar, the c.436delC variant has been reported as a possible founder pathogenic variant with striking phenotypic heterogeneity. In this retrospective study, we report on the clinical and molecular characteristics of additional 58 additional Qatari patients with WSS and compare them to international counterparts' findings. A total of 58 patients with WSS from 32 consanguineous families were identified. Ectodermal and endocrine (primary hypogonadism) manifestations were the most common presentations (100%), followed by diabetes mellitus (46%) and hypothyroidism (36%). Neurological manifestations were overlapping among patients with intellectual disability (ID) being the most common (75%), followed by sensorineural hearing loss (43%) and both ID and aggressive behavior (10%). Distinctive facial features were noted in all patients and extrapyramidal manifestations were uncommon (8.6%). This study is the largest to date on Qatari patients with WSS and highlights the high incidence and clinical heterogeneity of WSS in Qatar due to a founder variant c.436delC in the DCAF17 gene. Early suspicion of WSS among Qatari patients with hypogonadism and ID, even in the absence of other manifestations, would shorten the diagnostic odyssey, guide early and appropriate management, and avoid potential complications.

Genetic syndromes with diabetes: A systematic review

Previous reviews and clinical guidelines have identified 10-20 genetic syndromes associated with diabetes, but no systematic review has been conducted to date. We provide the first comprehensive catalog for syndromes with diabetes mellitus. We conducted a systematic review of MEDLINE, Embase, CENTRAL, PubMed, OMIM, and Orphanet databases for case reports, case series, and observational studies published between 1946 and January 15, 2020, that described diabetes mellitus in adults and children with monogenic or chromosomal syndromes. Our literature search identified 7,122 studies, of which 160 fulfilled inclusion criteria. Our analysis of these studies found 69 distinct diabetes syndromes. Thirty (43.5%) syndromes included diabetes mellitus as a cardinal clinical feature, and 56 (81.2%) were fully genetically elucidated. Sixty-three syndromes (91.3%) were described more than once in independent case reports, of which 59 (93.7%) demonstrated clinical heterogeneity. Syndromes associated with diabetes mellitus are more numerous and diverse than previously anticipated. While knowledge of the syndromes is limited by their low prevalence, future reviews will be needed as more cases are identified. The genetic etiologies of these syndromes are well elucidated and provide potential avenues for future gene identification efforts, aid in diagnosis and management, gene therapy research, and developing personalized medicine treatments.

Multimodal Evoked Potential Profiles in Woodhouse-Sakati Syndrome

PURPOSE

Woodhouse-Sakati syndrome is a rare autosomal recessive syndrome caused by homozygous mutations in the DCAF17 gene, characterized by marked neurologic and endocrine manifestations in the setting of brain iron accumulation and white matter lesions on neuroimaging. Here, we report electrophysiologic profiles in Woodhouse-Sakati syndrome and their possible value in understanding disease pathophysiology and phenotypic variability.

METHODS

Thirteen genetically confirmed Woodhouse-Sakati syndrome patients were evaluated via different evoked potential (EP) modalities, including brainstem auditory EPs, pattern reversal visual EPs, and somatosensory EPs to tibial and/or median nerves.

RESULTS

All EP modalities showed variable abnormalities. Pattern reversal visual EPs were recorded in all patients, with nine patients exhibiting abnormal results. From those, seven patients showed prolonged P100 latencies after stimulation of right and left eyes for each in turn. Two patients showed P100 latency abnormality after single eye stimulation recorded from midoccipital electrode. Median somatosensory EPs were recorded in 10 patients, with 6 patients having a prolonged cortical N19 response. Tibial somatosensory EP was performed for 11 patients, and 8 patients showed abnormal results where P37 cortical response was absent or prolonged, whereas peripheral potentials at the popliteal fossa were normal. Brainstem auditory EPs were abnormal only in two patients, with prolonged wave III and V latencies. Five patients with hearing impairment presented with normal brainstem auditory EP results.

CONCLUSIONS

Multiple EP abnormalities are observed in Woodhouse-Sakati syndrome patients, mainly in pattern reversal visual EPs and somatosensory EPs. These findings indicate potential myelin dysfunction that has a role in the underlying pathophysiology, disease course, and phenotypic variability.

A novel DCAF17 homozygous mutation in a girl with Woodhouse-Sakati syndrome and review of the current literature

Background Woodhouse-Sakati syndrome (WSS) (OMIM#241080) is an extremely rare multisystemic disease. Alopecia, hypogonadism, loss of hearing, hypothyroidism, diabetes mellitus (DM) and neurological disorders are the components of this syndrome. The syndrome is caused by homozygous or compound heterozygous mutations in DCAF17, and has recently been implicated in the development of both male and female gonads, thus resulting in hypogonadism. Case report A 16-year-old girl with consanguineous parents was admitted to our hospital with absence of breast development and amenorrhea. Hypogonadism was detected, in the form of hypergonadotropic hypogonadism. Whole-exome sequencing was used to identify the genetic etiology underlying the hypogonadism. A novel homozygous variant c.1091 + 1G > A was detected in DCAF17. Both parents were sequenced and identified as heterozygous for the same mutation. Conclusions We report a novel mutation detected in the DCAF17 gene and discuss the clinical findings in patients with previously reported mutations. Various manifestations of WSS, such as alopecia, endocrinological and neurological disorders, do not emerge until later in life, and therefore this situation can be challenging to diagnose particularly in pediatric cases, as in the present report. Careful attention should be paid to these additional findings, which may lead to early diagnosis and reduced genetic analysis costs, in patients with hypogonadism. In addition, there was no obvious genetic-phenotype correlation in reported cases.

The evolving role of genetic tests in reproductive medicine

Infertility is considered a major public health issue, and approximately 1 out of 6 people worldwide suffer from infertility during their reproductive lifespans. Thanks to technological advances, genetic tests are becoming increasingly relevant in reproductive medicine. More genetic tests are required to identify the cause of male and/or female infertility, identify carriers of inherited diseases and plan antenatal testing. Furthermore, genetic tests provide direction toward the most appropriate assisted reproductive techniques. Nevertheless, the use of molecular analysis in this field is still fragmented and cumbersome. The aim of this review is to highlight the conditions in which a genetic evaluation (counselling and testing) plays a role in improving the reproductive outcomes of infertile couples. We conducted a review of the literature, and starting from the observation of specific signs and symptoms, we describe the available molecular tests. To conceive a child, both partners' reproductive systems need to function in a precisely choreographed manner. Hence to treat infertility, it is key to assess both partners. Our results highlight the increasing importance of molecular testing in reproductive medicine.

Brain MR Imaging Findings in Woodhouse-Sakati Syndrome

BACKGROUND AND PURPOSE

Woodhouse-Sakati syndrome is a rare autosomal recessive disorder characterized by hypogonadism, alopecia, diabetes mellitus, and progressive extrapyramidal signs. The disease is caused by biallelic pathogenic variants in the DCAF17 gene. The purpose of this study was to describe the spectrum of brain MR imaging abnormalities in Woodhouse-Sakati syndrome.

MATERIALS AND METHODS

We reviewed brain MR images of 26 patients with a clinical and genetic diagnosis of Woodhouse-Sakati syndrome (12 males, 14 females; age range, 16-45 years; mean age, 26.6 years). Follow-up studies were conducted for 6 patients.

RESULTS

All patients had abnormal MR imaging findings. The most common abnormalities were a small pituitary gland (76.9%), pronounced basal ganglia iron deposition (73%), and white matter lesions in 69.2%. White matter lesions showed frontoparietal and periventricular predominance. All white matter lesions spared subcortical U-fibers and were nonenhanced. Prominent perivascular spaces (15.3%) and restricted diffusion in the splenium of the corpus callosum (7.6%) were less frequent findings. Follow-up studies showed expansion of white matter lesions with iron deposition further involving the red nucleus and substantia nigra. Older age was associated with a more severe degree of white matter lesions (P < .001).

CONCLUSIONS

Small pituitary gland, accentuated iron deposition in the globus pallidus, and nonenhancing frontoparietal/periventricular white matter lesions were the most noted abnormalities seen in our cohort. The pattern and extent of these findings were observed to correlate with older age, reflecting a possible progressive myelin destruction and/or axonal loss. The presence of pituitary hypoplasia and white matter lesions can further distinguish Woodhouse-Sakati syndrome from other neurodegenerative diseases with brain iron accumulation subtypes.

Phenotypic Variability of c.436delC DCAF17 Gene Mutation in Woodhouse-Sakati Syndrome

Case series

Patients: 38, female • 28, female • 41, female • 18, female • 23, male

Final Diagnosis: Woodhouse-Sakati syndrome

Symptoms: Hypogonadism • dystonia • alopecia • hearing loss • diabetes

Medication: —

Clinical Procedure: —

Specialty: Endocrinology and Metabolic

Advances in the Clinical Differential Diagnosis of Parkinson's Disease

The differential diagnosis of Parkinson's disease has widened considerably in recent years. This chapter aims to summarize the current knowledge on the clinical differential diagnoses of sporadic Parkinson's disease. As the number of monogenic familial Parkinson's disease variants and risk factors is growing, so is the number of appreciated etiologies of atypical parkinsonian and other pallidopyramidal syndromes. This work aims at summarizing the current knowledge on both motor and nonmotor neurological signs and symptoms that aid the clinical diagnosis of Parkinson's disease and its differential diagnoses.

Neurodegeneration with brain iron accumulation

Neurodegeneration with brain iron accumulation (NBIA) describes a heterogeneous group of inherited rare clinical and genetic entities. Clinical core symptoms comprise a combination of early-onset dystonia, pyramidal and extrapyramidal signs with ataxia, cognitive decline, behavioral abnormalities, and retinal and axonal neuropathy variably accompanying these core features. Increased nonphysiologic, nonaging-associated brain iron, most pronounced in the basal ganglia, is often termed the unifying characteristic of these clinically variable disorders, though occurrence and extent can be fluctuating or even absent. Neuropathologically, NBIA disorders usually are associated with widespread axonal spheroids and local iron accumulation in the basal ganglia. Postmortem, Lewy body, TDP-43, or tau pathology has been observed. Genetics have fostered ongoing progress in elucidating underlying pathophysiologic mechanisms of NBIA disorders. Ten associated genes have been established, with many more being suggested as new technologies and data emerge. Clinically, certain symptom combinations can suggest a specific genetic defect. Genetic tests, combined with postmortem neuropathology, usually make for the final disease confirmation. Despite these advances, treatment to date remains mainly symptomatic. This chapter reviews the established genetic defects leading to different NBIA subtypes, highlights phenotypic presentations to direct genetic testing, and briefly discusses the scarce available treatment options and upcoming challenges and future hopes of the field.

Clinical and imaging characteristics of late onset mitochondrial membrane protein-associated neurodegeneration (MPAN)

Young onset dementias present significant diagnostic challenges. We present the case of a 35-year-old Kuwaiti man with social withdrawal, drowsiness, irritability, anxiety, aphasia, memory loss, hypereflexia, and Parkinsonism. Brain MRI showed bilateral symmetric gradient echo hypointensities in the globi pallidi and substantiae nigrae. Left cortical hypometabolism was seen on brain fluorodeoxyglucose positron emission tomography. A cortical brain biopsy revealed a high Lewy body burden. Genetic testing revealed a homozygous p.T11M mutation in the C19orf12 gene consistent with mitochondrial membrane protein-associated neurodegeneration. This is the oldest onset age of MPAN reported.

Nomenclature of genetic movement disorders: Recommendations of the international Parkinson and movement disorder society task force

The system of assigning locus symbols to specify chromosomal regions that are associated with a familial disorder has a number of problems when used as a reference list of genetically determined disorders,including (I) erroneously assigned loci, (II) duplicated loci, (III) missing symbols or loci, (IV) unconfirmed loci and genes, (V) a combination of causative genes and risk factor genes in the same list, and (VI) discordance between phenotype and list assignment. In this article, we report on the recommendations of the International Parkinson and Movement Disorder Society Task Force for Nomenclature of Genetic Movement Disorders and present a system for naming genetically determined movement disorders that addresses these problems. We demonstrate how the system would be applied to currently known genetically determined parkinsonism, dystonia, dominantly inherited ataxia, spastic paraparesis, chorea, paroxysmal movement disorders, neurodegeneration with brain iron accumulation, and primary familial brain calcifications. This system provides a resource for clinicians and researchers that, unlike the previous system, can be considered an accurate and criterion-based list of confirmed genetically determined movement disorders at the time it was last updated.

Exome sequencing revealed a novel biallelic deletion in the DCAF17 gene underlying Woodhouse Sakati syndrome

Woodhouse Sakati syndrome (WSS, MIM 241080) is a rare autosomal recessive genetic condition characterized by alopecia, hypogonadism, hearing impairment, diabetes mellitus, learning disabilities and extrapydamidal manifestations. Sequence variants in the gene DCAF17, encoding nucleolar substrate receptor, were identified as the underlying cause of inherited WSS. Considerable phenotypic heterogeneity exists in WSS with regard to severity, organs involvement and age of onset, both in inter-familial and intra-familial cases. In this study, the genetic characterization of a consanguineous pedigree showing mild features of WSS was performed, followed by structural analysis of truncated protein. Exome sequencing identified a novel single base deletion variant (c.270delA; K90Nfs8*) in third exon of the gene DCAF17 (RefSeq; NM_025000), resulting in a truncated protein. Structural analysis of truncated DCAF17 revealed absence of amino acid residues crucial for interaction with DDB1. Taken together, the data confirmed the single base pair deletion as the underlying cause of this second report of WSS from Pakistan. This signifies the vital yet unexplored role of DCAF17 both in development and maintenance of adult tissues homeostasis.

The Use of High-Density SNP Array to Map Homozygosity in Consanguineous Families to Efficiently Identify Candidate Genes: Application to Woodhouse-Sakati Syndrome

Two consanguineous Qatari siblings presented for evaluation: a 17-4/12-year-old male with hypogonadotropic hypogonadism, alopecia, intellectual disability, and microcephaly and his 19-year-old sister with primary amenorrhea, alopecia, and normal cognition. Both required hormone treatment to produce secondary sex characteristics and pubertal development beyond Tanner 1. SNP array analysis of both probands was performed to detect shared regions of homozygosity which may harbor homozygous mutations in a gene causing their common features of abnormal pubertal development, alopecia, and variable cognitive delay. Our patients shared multiple homozygous genomic regions; ten shared regions were >1 Mb in length and constituted 0.99% of the genome. DCAF17, encoding a transmembrane nuclear protein of uncertain function, was the only gene identified in a homozygous region known to cause hypogonadotropic hypogonadism. DCAF17 mutations are associated with Woodhouse-Sakati syndrome, a rare disorder characterized by alopecia, hypogonadotropic hypogonadism, sensorineural hearing loss, diabetes mellitus, and extrapyramidal movements. Sequencing of the coding exons and flanking intronic regions of DCAF17 in the proband revealed homozygosity for a previously described founder mutation (c.436delC). Targeted DCAF17 sequencing of his affected sibling revealed the same homozygous mutation. This family illustrates the utility of SNP array testing in consanguineous families to efficiently and inexpensively identify regions of genomic homozygosity in which genetic candidates for recessive conditions can be identified.

Exome sequencing reveals a novel WDR45 frameshift mutation and inherited POLR3A heterozygous variants in a female with a complex phenotype and mixed brain MRI findings

WDR45 and POLR3A are newly recognized genes; each is associated with a distinct neurodegenerative disease. WDR45 is an X-linked gene associated with a dominant form of Neurodegeneration with Brain Iron Accumulation (NBIA), manifested by progressive disabilities, dystonia, cognitive decline, spastic paraplegia, neuropsychiatric abnormalities and iron deposition in the basal ganglia on brain imaging. POLR3A, on the other hand, is an autosomal gene, and its mutations cause a recessive form of a hypomyelination with leukodystrophy disease, also known as 4H syndrome, characterized by congenital Hypomyelination with thinning of the corpus callosum, Hypodontia and Hypogonadotropic Hypogonadism. We report on a female child with severe intellectual disability, aphasia, short stature, ataxia, failure to thrive and structural brain abnormalities. Brain MRI obtained in late infancy showed hypomyelination involving the central periventricular white matter and thinning of the corpus callosum with no evidence of iron accumulation. Brain MRI obtained in childhood showed stable hypomyelination, with progressive iron accumulation in the basal ganglia, in particular in the globus pallidus and substantia nigra. Whole Exome Sequencing (WES) identified a novel WDR45 frameshift deleterious mutation in Exon 9 (c.587-588del) and also revealed three POLR3A missense heterozygous variants. The first is a maternally inherited novel missense variant in exon 4 (c.346A > G). Exon 13 carried two heterozygous missense variants, a maternally inherited variant (c.1724A > T) and a paternally inherited variant (1745G > A). These variants are considered likely damaging. The patient's complex clinical phenotype and mixed brain MRI findings might be attributed to the confounding effects of the expression of these two mutant genes.

Neurodegeneration with brain iron accumulation: diagnosis and management

Neurodegeneration with brain iron accumulation (NBIA) encompasses a group of inherited disorders that share the clinical features of an extrapyramidal movement disorder accompanied by varying degrees of intellectual disability and abnormal iron deposition in the basal ganglia. The genetic basis of ten forms of NBIA is now known. The clinical features of NBIA range from rapid global neurodevelopmental regression in infancy to mild parkinsonism with minimal cognitive impairment in adulthood, with wide variation seen between and within the specific NBIA sub-type. This review describes the clinical presentations, imaging findings, pathologic features, and treatment considerations for this heterogeneous group of disorders.

Assessment of patients with isolated or combined dystonia: an update on dystonia syndromes

The clinical evaluation of a patient with dystonia is a stepwise process, beginning with classification of the phenomenology of the movement disorder(s), then formulation of the dystonia syndrome, which, in turn, leads to a targeted etiological differential diagnosis. In recent years, there have been significant advances in our understanding of the etiological basis of dystonia, aided especially by discoveries in imaging and genetics. In this review, we provide an update on the assessment of a patient with dystonia, including the phenomenology of dystonia and highlighting how to integrate clinical, imaging, blood, and neurophysiological investigations in order to formulate a dystonia syndrome. Evolving or emerging dystonia syndromes are reviewed, and potential etiologies of these as well as established dystonia syndromes listed to guide diagnostic testing. © 2013 Movement Disorder Society.

Alopecia and hypotrichosis as characteristic findings in Woodhouse-Sakati syndrome: report of a family with mutation in the C2orf37 gene

Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive disorder characterized by alopecia, hypogonadism, diabetes mellitus, intellectual disability, sensorineural deafness, extrapyramidal signs, and low insulinlike growth factor 1 levels. Inter- and intrafamilial phenotypic variability have been reported. Mutations in the C2orf37 gene cause WSS. The present report describes the clinical signs and symptoms of three affected siblings from a consanguineous Bedouin family from Kuwait. Direct sequencing of the C2orf37 gene revealed that the c.436delC (p.Ala147Hisfs*9) mutation was present in a homozygous state in all affected siblings and in a heterozygous state in the parents and a healthy sister. Nine C2orf37 mutations causing WSS have been identified. This family shared the mutation reported earlier in Saudi families and families of Bedouin tribes from Qatar and Israel. No phenotypic or genotypic correlation has been observed. Despite the great phenotypic variability of WSS, hypotrichosis has been observed in all individuals with WSS reported. This condition has not been reported in the dermatologic literature. WSS should be included in the differential diagnosis of syndromic congenital hypotrichosis.

Endocrine disorders in Woodhouse-Sakati syndrome: a systematic review of the literature

First described in 1983, Woodhouse-Sakati syndrome (WSS) is a rare autosomal recessive genetic disorder that leads to a spectrum of hypogonadal symptoms in adolescence. The responsible gene, DCAF17 located on chromosome 2q31.1, was discovered in 2008 and to date nine mutations have been reported in the literature. The aim of the study was to review WSS descriptively in the light of new case reports with focus on endocrine features. Phenotypic description of three patients (two females, one male) with WSS followed in the Endocrinology Department of the University Hospital of Nancy, France, and exhaustive review of the literature using the PUBMED database were performed. Of 72 patients from 29 families with documented WSS who were identified, 39 had undergone genetic testing. WSS was invariably associated with hypogonadism, decreased IGF1 and frontotemporal alopecia starting in childhood. In addition to this triad, some patients exhibited intellectual disabilities of varying severity (87 %), bilateral deafness (76 %), cervicofacial dystonia and limb pain (42 % of cases, rising to 89 % after 25 years) and diabetes (66 %, rising to 96 % after 25 years). The pathophysiology of WSS remains unclear.

Hypogonadism and neurological diseases

Affected patients with hypogonadism have unnaturally low amounts of sex hormones that produce male and female sex characteristics. Males who suffer from this condition lack testosterone, while females fail to produce enough estrogen. Hypogonadism may be present at birth, or it may take effect years later following injury or illness to the sex glands. Hypogonadism has remarkable associations with variable medical disorders; however, it is characterized by a distinctive association with variable neurological disorders: such as epilepsy, ataxia, dysmyelination, nerve muscle disease, movement disorders, mental retardation and deafness. The remarkable neurological diseases with hypogonadism should not basically be regarded as coincidental findings, but possibly related to an intrinsic pathophysiological association.

Phenotypic heterogeneity in Woodhouse-Sakati syndrome: two new families with a mutation in the C2orf37 gene

Hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome [also known as Woodhouse-Sakati syndrome (WSS)] is a rare autosomal recessive neuroendocrine and ectodermal disorder. The syndrome was first described by Woodhouse and Sakati in 1983, and 47 patients from 23 families have been reported so far. We report on an additional seven patients (four males and three females) from two highly consanguineous Arab families from Qatar, presenting with a milder phenotype of WSS. These patients show the spectrum of clinical features previously found in WSS, but lack evidence of diabetes mellitus and extrapyramidal symptoms. These two new families further illustrate the natural course and the interfamilial phenotypic variability of WSS that may lead to challenges in making the diagnosis. In addition, our study suggests that WSS may not be as infrequent in the Arab world as previously thought.

Genetics of neurodegeneration with brain iron accumulation

The condition originally called Hallervorden-Spatz syndrome is a collection of related disorders involving abnormal iron accumulation in the basal ganglia, usually manifesting with a movement disorder. To date, mutations in the following genes have been associated with neurodegeneration with brain iron accumulation (NBIA) phenotypes: PANK2, PLA2G6, FA2H, ATP13A2, C2orf37, CP, and FTL. This collection, now classified under the umbrella term NBIA, continues to evolve as new genes and associated phenotypes are recognized. As this body of information continues to grow, better approaches to diagnosis and treatment have become available. Continued investigations of the underlying pathogenesis of disease, with a focus on lipid, iron, and energy metabolism, will lead to the identification of new therapeutic targets.

RNA microarray analysis in prenatal mouse cochlea reveals novel IGF-I target genes: implication of MEF2 and FOXM1 transcription factors

Background

Insulin-like growth factor-I (IGF-I) provides pivotal cell survival and differentiation signals during inner ear development throughout evolution. Homozygous mutations of human IGF1 cause syndromic sensorineural deafness, decreased intrauterine and postnatal growth rates, and mental retardation. In the mouse, deficits in IGF-I result in profound hearing loss associated with reduced survival, differentiation and maturation of auditory neurons. Nevertheless, little is known about the molecular basis of IGF-I activity in hearing and deafness.

Methodology/Principal Findings

A combination of quantitative RT-PCR, subcellular fractionation and Western blotting, along with in situ hybridization studies show IGF-I and its high affinity receptor to be strongly expressed in the embryonic and postnatal mouse cochlea. The expression of both proteins decreases after birth and in the cochlea of E18.5 embryonic Igf1^−/− null mice, the balance of the main IGF related signalling pathways is altered, with lower activation of Akt and ERK1/2 and stronger activation of p38 kinase. By comparing the Igf1^−/− and Igf1^+/+ transcriptomes in E18.5 mouse cochleae using RNA microchips and validating their results, we demonstrate the up-regulation of the FoxM1 transcription factor and the misexpression of the neural progenitor transcription factors Six6 and Mash1 associated with the loss of IGF-I. Parallel, in silico promoter analysis of the genes modulated in conjunction with the loss of IGF-I revealed the possible involvement of MEF2 in cochlear development. E18.5 Igf1^+/+ mouse auditory ganglion neurons showed intense MEF2A and MEF2D nuclear staining and MEF2A was also evident in the organ of Corti. At P15, MEF2A and MEF2D expression were shown in neurons and sensory cells. In the absence of IGF-I, nuclear levels of MEF2 were diminished, indicating less transcriptional MEF2 activity. By contrast, there was an increase in the nuclear accumulation of FoxM1 and a corresponding decrease in the nuclear cyclin-dependent kinase inhibitor p27^Kip1.

Conclusions/Significance

We have defined the spatiotemporal expression of elements involved in IGF signalling during inner ear development and reveal novel regulatory mechanisms that are modulated by IGF-I in promoting sensory cell and neural survival and differentiation. These data will help us to understand the molecular bases of human sensorineural deafness associated to deficits in IGF-I.

Primary hypogonadism, partial alopecia, and Mullerian hypoplasia: report of a third family and review

Two sisters presented with partial alopecia, primary hypergonadotropic hypogonadism and Mullerian hypoplasia associated with mild mental retardation, microcephaly, flat occiput, sparse eyebrows, absence of breast tissue, absent ovaries, mild-moderate dorsal kyphosis, thin upper lip and unilateral sensorioneural deafness in one of them. They were the product of a Turkish consanguineous marriage. The clinical course for our patients is similar to two families reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622] and Megarbane et al. [Megarbane et al. (2003) Am J Med Genet Part A 119A:214-217]. This report supports the literature by proposing an autosomal recessive syndrome which was firstly reported by Al-Awadi et al. [Al-Awadi et al. (1985) Am J Med Genet 22:619-622]. This condition may be due to a founder mutation.

Mutations in C2orf37, encoding a nucleolar protein, cause hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome

Hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome (also referenced as Woodhouse-Sakati syndrome) is a rare autosomal recessive multisystemic disorder. We have identified a founder mutation consisting of a single base-pair deletion in C2orf37 in eight families of Saudi origin. Three other loss-of-function mutations were subsequently discovered in patients of different ethnicities. The gene encodes a nucleolar protein of unknown function, and the cellular phenotype observed in patient lymphoblasts implicates a role for the nucleolus in the pathogenesis of this disease. Our findings expand the list of human disorders linked to the nucleolus and further highlight the developmental and/or maintenance functions of this organelle.

Alopecia, neurological defects, and endocrinopathy syndrome caused by decreased expression of RBM28, a nucleolar protein associated with ribosome biogenesis

Single-gene disorders offer unique opportunities to shed light upon fundamental physiological processes in humans. We investigated an autosomal-recessive phenotype characterized by alopecia, progressive neurological defects, and endocrinopathy (ANE syndrome). By using homozygosity mapping and candidate-gene analysis, we identified a loss-of-function mutation in RBM28, encoding a nucleolar protein. RBM28 yeast ortholog, Nop4p, was previously found to regulate ribosome biogenesis. Accordingly, electron microscopy revealed marked ribosome depletion and structural abnormalities of the rough endoplasmic reticulum in patient cells, ascribing ANE syndrome to the restricted group of inherited disorders associated with ribosomal dysfunction.