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| Lamb-Shaffer syndrome | |
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| Autosomal dominant pattern is the inheritance manner of this condition | |
| Specialty | Medical genetics |
Lamb-Shaffer syndrome is a rare autosomal dominant condition. [1] Less than 40 cases have been reported by 2018.
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| Lamb-Shaffer syndrome | |
|---|---|
| | |
| Autosomal dominant pattern is the inheritance manner of this condition | |
| Specialty | Medical genetics |
Lamb-Shaffer syndrome is a rare autosomal dominant condition. [1] Less than 40 cases have been reported by 2018.
Clinical features include [2]
This condition is caused by mutations in the SRY-related HMG-box ( SOX5 ) gene. [3] This gene encodes a protein in the family of transcription factors involved in the regulation of embryonic development and in the determination of the cell fate.
The gene is located on the short arm of chromosome 12 (12p12).
A study published in 2019 examining 34 families shows that 74% (25/34 families) of the condition are likely to be of de novo occurrence, as the variants could not be detected in parental blood samples. In 15% (5/34 families) of the patients the condition was likely inherited from a mosaic parent. In 3% (1/34), the condition was inherited from an affected parent. [4] This means that the majority of the patients have parents who are unaffected whereas inheritance is also possible.
How this mutation causes the clinical picture is not currently clear.[ citation needed ]
The diagnosis may be suspected on the basis of the constellation of clinical features but may only be determined by a genetic test. The full exome sequencing test is used to determine the partial deletion, deletion,or mutation to the SOX5 gene. It is made by sequencing the SOX5 gene responsible for the cells that facilitate information transferring in the brain. Symptoms of Lamb-Shaffer syndrome include fine and gross motor delays, speech delay, global developmental delay,hypotonia and issues with vision, commonly misdiagnosed for autism.
There is currently no curative treatment for this condition. Supportive management is all that is currently available.
This is a rare condition with a prevalence of < 1/106. The total number of cases reported to date is <550. [5]
This condition was first described by Lamb et al in 2012 [6]
A unibrow is a single eyebrow created when the two eyebrows meet in the middle above the bridge of the nose. The hair above the bridge of the nose is of the same color and thickness as the eyebrows, such that they converge to form one uninterrupted line of hair.
Kabuki syndrome is a rare congenital disorder of genetic origin. It affects multiple parts of the body, with varying symptoms and severity, although the most common is the characteristic facial appearance.
22q13 deletion syndrome, known as Phelan–McDermid syndrome (PMS), is a genetic disorder caused by deletions or rearrangements on the q terminal end of chromosome 22. Any abnormal genetic variation in the q13 region that presents with significant manifestations (phenotype) typical of a terminal deletion may be diagnosed as 22q13 deletion syndrome. There is disagreement among researchers as to the exact definition of 22q13 deletion syndrome. The Developmental Synaptopathies Consortium defines PMS as being caused by SHANK3 mutations, a definition that appears to exclude terminal deletions. The requirement to include SHANK3 in the definition is supported by many but not by those who first described 22q13 deletion syndrome.
Pitt–Hopkins syndrome (PTHS) is a rare genetic disorder characterized by developmental delay, epilepsy, distinctive facial features, and possible intermittent hyperventilation followed by apnea. Pitt–Hopkins syndrome can be marked by intellectual disabilities as well as problems with socializing. It is part of the clinical spectrum of Rett-like syndromes.
Sotos syndrome is a rare genetic disorder characterized by excessive physical growth during the first years of life. Excessive growth often starts in infancy and continues into the early teen years. The disorder may be accompanied by autism, mild intellectual disability, delayed motor, cognitive, and social development, hypotonia, and speech impairments. Children with Sotos syndrome tend to be large at birth and are often taller, heavier, and have relatively large skulls (macrocephaly) than is normal for their age. Signs of the disorder, which vary among individuals, include a disproportionately large skull with a slightly protrusive forehead, large hands and feet, large mandible, hypertelorism, and downslanting eyes. Clumsiness, an awkward gait, and unusual aggressiveness or irritability may also occur.
9q34 deletion syndrome is a rare genetic disorder. Terminal deletions of chromosome 9q34 have been associated with childhood hypotonia, a distinctive facial appearance and developmental disability. The facial features typically described include arched eyebrows, small head circumference, midface hypoplasia, prominent jaw and a pouting lower lip. Individuals with this disease may often have speech impediments, such as speech delays. Other characteristics of this disease include: epilepsy, congenital and urogenital defects, microcephaly, corpulence, and psychiatric disorders. From analysis of chromosomal breakpoints, as well as gene sequencing in suggestive cases, Kleefstra and colleagues identified EHMT1 as the causative gene. This gene is responsible for producing the protein histone methyltransferase which functions to alter histones. Ultimately, histone methyltransferases are important in deactivating certain genes, needed for proper growth and development. Moreover, a frameshift, missense, or nonsense error in the coding sequence of EHMT1 can result in this condition in an individual.
Ogden syndrome, also known as N-terminal acetyltransferase deficiency (NATD), is an X-linked disorder of infancy comprising a distinct combination of distinctive craniofacial features producing an aged appearance, growth failure, hypotonia, global developmental delays, cryptorchidism, and spontaneous cardiac arrhythmias. The first family was identified in Ogden, Utah, with five affected boys in two generations of family members. A mutation was identified as a c.109T>C (p.Ser37Pro) variant in NAA10, a gene encoding the catalytic subunit of the major human N-terminal acetyltransferase enzyme system (NatA). This same mutation was identified in a second unrelated family, with three affected boys in two generations. This severe genetic disorder has provisionally been named Ogden syndrome, as this is the city where the first affected family resides.
Wiedemann–Steiner syndrome(WSS) is a rare genetic disorder that causes developmental delay, unusual facial features, short stature, and reduction in muscle tone (hypotonia). The syndrome was originally described in 1989 by Hans-Rudolf Wiedemann. The genetic basis for the syndrome was identified by Dr. Wendy D. Jones in 2012. The first case was reported in 1989 by Wiedemann and colleagues which reported a Caucasian boy with pre- and postnatal growth deficiency, psychomotor delay, and a round and flat face, short nose, widely spaced eyes, long philtrum, short palpebral fissures, low-set ears, and high-arched palate. Other findings included an alternating convergent squint, dilatation of the renal calyces, and short and thick limbs. Later decades brought about more finding and descriptions of this disorder.
AHDC1 is a gene, changes in which are found through clinical studies to cause an array of symptoms in affected children known collectively as Xia-Gibbs Syndrome, including global developmental delay, global hypotonia, obstructive sleep apnoea and seizures.
Xia-Gibbs syndrome, is genetic disorder caused by a heterozygous mutation in the AHDC1 gene on chromosome 1p36.
Lysine demethylase 6B is a protein that in humans is encoded by the KDM6B (JMJD3) gene.
Fryns-Aftimos syndrome is a rare chromosomal condition and is associated with pachygyria, severe mental retardation, epilepsy and characteristic facial features. This syndrome is a malformation syndrome, characterized by numerous facial dysmorphias not limited to hypertelorism, iris or retinal coloboma, cleft lip, and congenital heart defects. This syndrome has been seen in 30 unrelated people. Characterized by a de novo mutation located on chromosome 7p22, there is typically no family history prior to onset. The severity of the disorder can be determined by the size of the deletion on 7p22, enveloping the ACTB gene and surrounding genes, which is consistent with a contiguous gene deletion syndrome. Confirming a diagnosis of Fryns-Aftimos syndrome typically consists of serial single-gene testing or multigene panel of genes of interest or exome sequencing.
ZTTK syndrome is a rare multisystem disease caused in humans by a genetic mutation of the SON gene. Common symptoms include developmental delay and often light to severe intellectual disability.
CDK13-related disorder, also known as congenital heart defects, dysmorphic facial features and intellectual developmental disorder (CHDFIDD), is a very rare autosomal dominant genetic condition characterised by congenital heart defects, intellectual disability and characteristic facial features. Those affected typically have motor and language delays, low muscle tone and gastrointestinal dysmotility. Facial features include a wide nasal bridge, widely-spaced eyes, prominent, low-set ears, a flat nose tip and a small mouth. Less common features include congenital spinal abnormalities, hearing loss or seizures.
DeSanto-Shinawi (DESSH) syndrome is a rare genetic disorder caused by genetic variations (mutations) in a gene called WW Domain-Containing Adaptor with Coiled-coil Region. The condition was first described in 2015 in six individuals. The prevalence of DESSH syndrome is unknown at this time, but 25 individuals have been so far described in the medical literature. However, many other individuals with this condition are being studied and characterized. With the increasing utilization of exome and whole genome sequencing, it is anticipated that many more individuals will be identified.
SYNGAP1-related intellectual disability is a monogenetic developmental and epileptic encephalopathy that affects the central nervous system. Symptoms include intellectual disability, epilepsy, autism, sensory processing deficits, hypotonia and unstable gait.
Jordan's syndrome (JS) or PPP2R5D-related intellectual disability is a rare autosomal dominant neurodevelopmental disorder caused by de novo mutations in the PPP2R5D gene. It is characterized by hypotonia, intellectual disability, and macrocephaly. Children with JS may also have epilepsy or meet criteria for diagnosis with autism spectrum disorder.
CHAMP1-associated intellectual disability syndrome, also known as autosomal dominant intellectual disability type 40, is a rare genetic disorder characterized by intellectual disabilities, developmental delays, facial dysmorphisms, and other anomalies.
Severe intellectual disability-progressive spastic diplegia syndrome is a rare novel genetic disorder characterized by severe intellectual disabilities, ataxia, craniofacial dysmorphisms, and muscle spasticity. It is a type of autosomal dominant syndromic intellectual disability.
Beck–Fahrner syndrome, also known as BEFAHRS and TET3 deficiency, is a rare genetic disorder caused by mutations of the TET3 gene. The clinical presentation varies among individuals, but typically includes global developmental delay, slow progress in mental and physical activities, autism, decreased muscle tone, epilepsy and dysmorphic features.