SATB2-associated syndrome: characterization of skeletal features and of bone fragility in a prospective cohort of 19 patients.

BACKGROUND: Individuals with pathogenic variants in SATB2 display intellectual disability, speech and behavioral disorders, dental abnormalities and often features of Pierre Robin sequence. SATB2 encodes a transcription factor thought to play a role in bone remodeling. The primary aim of our study was to systematically review the skeletal manifestations of SATB2-associated syndrome. For this purpose, we performed a non-interventional, multicenter cohort study, from 2017 to 2018. We included 19 patients, 9 females and 10 males ranging in age from 2 to 19 years-old. The following data were collected prospectively for each patient: clinical data, bone markers and calcium and phosphate metabolism parameters, skeletal X-rays and bone mineral density. RESULTS: Digitiform impressions were present in 8/14 patients (57%). Vertebral compression fractures affected 6/17 patients (35%). Skeletal demineralization (16/17, 94%) and cortical thinning of vertebrae (15/17) were the most frequent radiological features at the spine. Long bones were generally demineralized (18/19). The distal phalanges were short, thick and abnormally shaped. C-telopeptide (CTX) and Alkaline phosphatase levels were in the upper normal values and osteocalcin and serum procollagen type 1 amino-terminal propeptide (P1NP) were both increased. Vitamin D insufficiency was frequent (66.7%). CONCLUSION: We conclude that SATB2 pathogenic variants are responsible for skeletal demineralization and osteoporosis. We found increased levels of bone formation markers, supporting the key role of SATB2 in osteoblast differentiation. These results support the need for bone evaluation in children and adult patients with SATB2-associated syndrome (SAS).

Deciphering the natural history of SCA7 in children.

BACKGROUND AND PURPOSE: Childhood-onset autosomal dominant cerebellar ataxia type 7 (SCA7) is a severe disease which leads to premature loss of ambulation and death. Early diagnosis of SCA7 is of major importance for genetic counselling and still relies on specific genetic testing, driven by clinical expertise. However, the precise phenotype and natural history of paediatric SCA7 has not yet been fully described. Our aims were to describe the natural history of SCA7 in a large multicentric series of children of all ages, and to find correlates to variables defining this natural history. METHODS: We collected and analysed clinical data from 28 children with proven SCA7. All had clinical manifestations of SCA7 and either a definite number of CAG repeats in ATXN7 or a long expansion > 100 CAG. RESULTS: We identified four clinical presentation patterns related to age at onset. Children of all age groups had cerebellar atrophy and retinal dystrophy. Our data, combined with those in the literature, suggest that definite ranges of CAG repeats determine paediatric SCA7 subtypes. The number of CAG repeats inversely correlated to all variables of the natural history. Age at gait ataxia onset correlated accurately to age at loss of walking ability and to age at death. CONCLUSION: SCA7 in children has four presentation patterns that are roughly correlated to the number of CAG repeats. Our depiction of the natural history of SCA7 in children may help in monitoring the effect of future therapeutic trials.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients.

BACKGROUND: Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification. OBJECTIVES: To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations. METHODS: We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined. CONCLUSIONS: A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

Dermatological manifestations in Noonan syndrome: a prospective multicentric study of 129 patients positive for mutation.

BACKGROUND: Data on dermatological manifestations of Noonan syndrome (NS) remain heterogeneous and are based on limited dermatological expertise. OBJECTIVES: To describe the dermatological manifestations of NS, compare them with the literature findings, and test for dermatological phenotype-genotype correlations with or without the presence of PTPN11 mutations. METHODS: We performed a large 4-year, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Overall, 129 patients with NS were enrolled, including 65 patients with PTPN11-NS, 34 patients with PTPN11-NS with multiple lentigines (NSML), and 30 patients with NS who had a mutation other than PTPN11. Easy bruising was the most frequent dermatological finding in PTPN11-NS, present in 53·8% of patients. Multiple lentigines and café-au-lait macules (n ≥ 3) were present in 94% and 80% of cases of NSML linked to specific mutations of PTPN11, respectively. Atypical forms of NSML could be associated with NS with RAF1 or NRAS mutations. In univariate analysis, patients without a PTPN11 mutation showed (i) a significantly higher frequency of keratinization disorders (P = 0·001), including keratosis pilaris (P = 0·005), ulerythema ophryogenes (P = 0·0001) and palmar and/or plantar hyperkeratosis (P = 0·06, trend association), and (ii) a significantly higher frequency of scarce scalp hair (P = 0·035) and scarce or absent eyelashes (P = 0·06, trend association) than those with PTPN11 mutations. CONCLUSIONS: The cutaneous phenotype of NS with a PTPN11 mutation is generally mild and nonspecific, whereas the absence of a PTPN11 mutation is associated with a high frequency of keratinization disorders and hair abnormalities.

Refining the phenotype associated with biallelic DNAJC21 mutations.

Inherited bone marrow failure syndromes (IBMFS) are caused by mutations in genes involved in genomic stability. Although they may be recognized by the association of typical clinical features, variable penetrance and expressivity are common, and clinical diagnosis is often challenging. DNAJC21, which is involved in ribosome biogenesis, was recently linked to bone marrow failure. However, the specific phenotype and natural history remain to be defined. We correlate molecular data, phenotype, and clinical history of 5 unreported affected children and all individuals reported in the literature. All patients present features consistent with IBMFS: bone marrow failure, growth retardation, failure to thrive, developmental delay, recurrent infections, and skin, teeth or hair abnormalities. Additional features present in some individuals include retinal abnormalities, pancreatic insufficiency, liver cirrhosis, skeletal abnormalities, congenital hip dysplasia, joint hypermobility, and cryptorchidism. We suggest that DNAJC21-related diseases constitute a distinct IBMFS, with features overlapping Shwachman-Diamond syndrome and Dyskeratosis congenita, and additional characteristics that are specific to DNAJC21 mutations. The full phenotypic spectrum, natural history, and optimal management will require more reports. Considering the aplastic anemia, the possible increased risk for leukemia, and the multisystemic features, we provide a checklist for clinical evaluation at diagnosis and regular follow-up.

INTU-related oral-facial-digital syndrome type VI: A confirmatory report.

Oral-facial-digital (OFD) syndromes are a subgroup of ciliopathies distinguished by the co-occurrence of hamartomas and/or multiple frenula of the oral region and digital anomalies. Several clinical forms of OFD syndromes are distinguished by their associated anomalies and/or inheritance patterns, and at least 20 genetic types of OFD syndromes have been delineated. We describe here a child with preaxial and postaxial polydactyly, lingual hamartoma, a congenital heart defect, delayed development and cerebellar peduncles displaying the molar tooth sign. Whole-exome sequencing and SNP array identified compound heterozygous variants in the INTU gene, which encodes a protein involved in the positioning of the ciliary basal body. INTU is a subunit of the CPLANE multiprotein complex essential for the assembly of IFT-A particles and intraflagellar transport. This report of a second patient with INTU-related OFD syndrome and the further delineation of its neuroimaging and skeletal phenotype now allow INTU-related OFD syndromes to be classified within the OFD syndrome type VI group. Patients display a phenotype similar to that of mice with a hypomorphic mutation of Intu, but with the addition of a heart defect.

Pachydermoperiostosis: The value of molecular diagnosis.

BACKGROUND: Pachydermoperiostosis is a rare autosomal recessive genetic disorder characterized by the association of periostosis and pachydermia. To date, two genes involved in prostaglandin metabolism, HPGD and SLCO2A1, have been identified. PATIENTS AND METHODS: A 7-year-old girl presented digital clubbing of the hands and feet, curved nails, hyperhidrosis, and pachydermia, as well as eczema of the trunk and limbs. The diagnosis of pachydermoperiostosis was confirmed by the detection of a homozygous mutation in the HPGD gene. The second case concerned a 41-year-old male with acral and cephalic pachydermia (cutis verticis gyrata), and palmoplantar keratoderma. Bone X-rays showed changes in the distal ends of several bones. The diagnosis of pachydermoperiostosis was confirmed by the detection of a homozygous mutation in the SLCO2A1 gene. DISCUSSION: The genotype/phenotype correlation suggests that patients with SLCO2A1 mutations will develop the symptoms later in life, but that these will be more severe, with a greater likelihood of cutis verticis gyrata and joint involvement compared with patients presenting HPGD mutations. In addition, hereditary enteropathy has recently been described in patients with SLCO2A1 mutations, which could account for the gastrointestinal picture seen in the second patient. Finally, on account of cases involving myelofibrosis associated with mutations in the SLCO2A gene, these patients should have a hematologic follow-up. CONCLUSION: Given the genotype/phenotype correlations illustrated by these cases, it would appear useful to propose molecular diagnosis for patients presenting pachydermoperiostosis.

Molecular, clinical and neuropsychological study in 31 patients with Kabuki syndrome and KMT2D mutations.

Kabuki syndrome (KS-OMIM 147920) is a rare developmental disease characterized by the association of multiple congenital anomalies and intellectual disability. This study aimed to investigate intellectual performance in children with KS and link the performance to several clinical features and molecular data. We recruited 31 children with KMT2D mutations who were 6 to 16 years old. They all completed the Weschler Intelligence Scale for Children, fourth edition. We calculated all indexes: the Full Scale Intellectual Quotient (FSIQ), Verbal Comprehension Index (VCI), Perceptive Reasoning Index (PRI), Processing Speed Index (PSI), and Working Memory Index (WMI). In addition, molecular data and several clinical symptoms were studied. FSIQ and VCI scores were 10 points lower for patients with a truncating mutation than other types of mutations. In addition, scores for FSIQ, VCI and PRI were lower for children with visual impairment than normal vision. We also identified a discrepancy in indexes characterized by high WMI and VCI and low PRI and PSI. We emphasize the importance of early identification and intensive care of visual disorders in patients with KS and recommend individual assessment of intellectual profile.

Beckwith-Wiedemann syndrome and long QT syndrome due to familial-balanced translocation t(11;17)(p15.5;q21.3) involving the KCNQ1 gene.

We report a child with Beckwith-Wiedemann syndrome (BWS) as the consequence of an apparently balanced, maternally inherited reciprocal translocation t(11;17)(p15.5;q21.3). His mother and aunt, who inherited the translocation from their father, did not have BWS. At birth, long QT syndrome (LQTS) was diagnosed in this child and, secondarily, among apparently healthy family members carrying the translocation. By FISH analysis, the breakpoint in 11p15.5 interrupts the KCNQ1 gene between exons 2 and 10 and causes a loss of methylation of the IC2 (and thus BWS) on the maternally inherited der(11) chromosome. To explain the presence of LQTS segregating with the t(11;17) translocation in this family, we hypothesize that the translocation that interrupts KCNQ1 allow translation of an abnormal short allele that interferes in a dominant negative way with the normal isoform 1 of KCNQ1 in the heart (where this allele is not subject to parental imprint). This appears to be the first report of BWS with congenital LQTS, which should be considered as a rare but serious complication to be searched systematically in patients with BWS due to 11p15 rearrangements.

[A lethal variant of Netherton syndrome in a large inbred family]. / Forme létale de syndrome de Netherton au sein d'une famille multiplex consanguine.

Netherton syndrome is a rare autosomal recessive disorder characterized by the triad of ichthyosiform erythrodermia, typical hair dysplasia, and severe atopic features. The broad range of variable expression of this disease is well described and 20% of complications occur during the neonatal period such as hypernatremic dehydration, electrolyte imbalances, recurrent or severe infections, and failure to thrive. Mutation of the SPINK5 gene has been identified as disease-causing in Netherton syndrome, but the pathophysiology still remains unclear. Almost all SPINK5 mutations result in the absence of the serine-protease inhibitor LEKTI protein in both keratinocytes and lymphocytes. In this study, we report on a severe form of Netherton syndrome observed in three patients within a large inbred Rom family. All of them died in the first months of life despite early treatment. They were found to be homozygous for the c.1431-12G>A SPINK5 gene mutation, which has not been associated with a lethal form of the disease thus far. This family illustrates the extreme phenotype of Netherton disease of neonatal onset. Molecular diagnosis allowed further genetic counseling and prenatal testing during other pregnancies.

De novo unbalanced translocation 2;4 characterized by metaphase CGH and array CGH in a child with mental retardation and dysmorphic features.

BACKGROUND: It is known from postnatal diagnosis that imbalances of the subtelomeric regions contribute significantly to idiopathic mental retardation. PATIENT AND METHODS: We report a case of a 4-year-old child with growth retardation, minor physical abnormalities, hypotonia and developmental delay associated with a derivative chromosome 4. Molecular cytogenetic investigations were performed to characterize the chromosomal rearrangement. RESULTS: Multi fluorescence in situ hybridization revealed the presence of chromosome 2 material on the derivative chromosome 4. Metaphase comparative genomic hybridization detected a terminal 4q34 deletion. Array CGH analysis could precise breakpoints with duplication 2q36 → qter. The clinical phenotype was similar to those described in cases with a trisomy 2qter. CONCLUSION: This study emphasizes the value of array CGH to detect or characterize chromosome rearrangements in mentally retarded patients. Unlike metaphase CGH, the high resolution of array CGH in subtelomeric regions allows an accurate description of chromosomal aberrations.