Cryptorchidism, and Unsteady gait

X-linked intellectual disability, Snyder type is a rare X-linked intellectual disability syndrome characterized by hypotonia, asthenic build with diminished muscle mass, severe generalized psychomotor delay, unsteady gait and moderate to severe intellectual disability, as well as a long, thin, asymmetrical face with prominent lower lip, long fingers and toes and nasal, dysarthric or absent speech. Bone abnormalities (e.g., osteoporosis, kyphoscoliosis, fractures, joint contractures) are also characteristic. Myoclonic, or myoclonic-like, seizures and renal abnormalities have been associated in some patients.

X-LINKED INTELLECTUAL DISABILITY, SNYDER TYPE Is also known as snyder-robinson syndrome|snyder-robinson mental retardation syndrome|srs

• Intellectual disability
• Seizures
• Global developmental delay
• Short stature
• Generalized hypotonia

SOURCES: MESH ORPHANET OMIM MENDELIAN

Spondylo-ocular syndrome is a very rare association of spinal and ocular manifestations that is characterized by dense cataracts, and retinal detachment along with generalized osteoporosis and platyspondyly. Mild craniofacial dysphormism has been reported including short neck, large head and prominent eyebrows.

• Intellectual disability
• Short stature
• Generalized hypotonia
• Hearing impairment
• Hypertelorism

SOURCES: ORPHANET OMIM MENDELIAN

Ehlers-Danlos syndrome, kyphoscoliotic type (EDKT) is a form of Ehlers-Danlos syndrome characterized by severe hypotonia and kyphoscoliosis at birth, generalized joint hyperextensibility and ocular globe fragility.

EHLERS-DANLOS SYNDROME, KYPHOSCOLIOTIC TYPE Is also known as eds vi|eds6|ehlers-danlos syndrome, oculoscoliotic type|ehlers-danlos syndrome, ocular-scoliotic type|eds, oculoscoliotic type|eds6a, formerly|nevo syndrome|eds via|ehlers-danlos syndrome, type vi|ehlers-danlos syndrome, type via, formerly|eds, kyphoscoli

• Generalized hypotonia
• Scoliosis
• Muscle weakness
• Muscular hypotonia
• Cryptorchidism

SOURCES: ORPHANET OMIM MESH MENDELIAN

Cerebro-facio-thoracic dysplasia or Pascual-Castroviejo syndrome type 1 is a rare syndrome characterized by facial dysmorphism, intellectual deficit and costovertebral abnormalities.

CEREBROFACIOTHORACIC DYSPLASIA Is also known as pascual-castroviejo syndrome type 1|cerebrofaciothoracic dysplasia

• Intellectual disability
• Global developmental delay
• Short stature
• Generalized hypotonia
• Microcephaly

SOURCES: ORPHANET MESH OMIM MENDELIAN

Najm type X-linked intellectual deficit is a rare cerebellar dysgenesis syndrome characterized by variable clinical manifestations ranging from mild intellectual deficit with or without congenital nystagmus, to severe cognitive impairment associated with cerebellar and pontine hypoplasia/atrophy and abnormalities of cortical development.

X-LINKED INTELLECTUAL DISABILITY, NAJM TYPE Is also known as fgs1|keller syndrome|fg syndrome|fgs|x-linked intellectual disability-microcephaly-pontocerebellar hypoplasia syndrome|mental retardation, large head, imperforate anus, congenital hypotonia, and partial agenesis of corpus callosum|fg syndrome 1|micpch

• Intellectual disability
• Seizures
• Global developmental delay
• Short stature
• Generalized hypotonia

SOURCES: OMIM ORPHANET MENDELIAN

Rubinstein-Taybi syndrome is a multiple congenital anomaly syndrome characterized by mental retardation, postnatal growth deficiency, microcephaly, broad thumbs and halluces, and dysmorphic facial features. The facial appearance is striking, with highly arched eyebrows, long eyelashes, downslanting palpebral fissures, broad nasal bridge, beaked nose with the nasal septum, highly arched palate, mild micrognathia, and characteristic grimacing or abnormal smile. Affected individuals also have an increased risk of tumor formation (Rubinstein and Taybi, 1963; review by Hennekam, 2006).Floating-Harbor syndrome (OMIM ), which shows phenotypic overlap with Rubinstein-Taybi syndrome, is caused by mutation in the SRCAP gene (OMIM ), a coactivator for CREBBP. Genetic Heterogeneity of Rubinstein-Taybi SyndromeRubinstein-Taybi syndrome-1 (RSTS1) constitutes about 50 to 70% of patients with the disorder. Rubinstein-Taybi syndrome-2 (RSTS2 ) comprises about 3% of patients and is primarily due to de novo heterozygous mutation in the EP300 gene (OMIM ) on chromosome 22q13 (Bartsch et al., 2010).See also chromosome 16p13.3 deletion syndrome (OMIM ), a severe form of Rubinstein-Taybi syndrome resulting from a contiguous gene deletion involving the CREBBP gene as well as other neighboring genes.

RUBINSTEIN-TAYBI SYNDROME 1; RSTS1 Is also known as broad thumbs and great toes, characteristic facies, and mental retardation|rubinstein syndrome|rsts|broad thumb-hallux syndrome

• Intellectual disability
• Seizures
• Short stature
• Generalized hypotonia
• Hearing impairment

SOURCES: OMIM MENDELIAN

Myotonic dystrophy is an autosomal dominant disorder characterized mainly by myotonia, muscular dystrophy, cataracts, hypogonadism, frontal balding, and ECG changes. The genetic defect in DM1 results from an amplified trinucleotide repeat in the 3-prime untranslated region of a protein kinase gene. Disease severity varies with the number of repeats: normal individuals have 5 to 37 repeats, mildly affected persons have 50 to 150 repeats, patients with classic DM have 100 to 1,000 repeats, and those with congenital onset can have more than 2,000 repeats. The disorder shows genetic anticipation, with expansion of the repeat number dependent on the sex of the transmitting parent. Alleles of 40 to 80 repeats are usually expanded when transmitted by males, whereas only alleles longer than 80 repeats tend to expand in maternal transmissions. Repeat contraction events occur 4.2 to 6.4% of the time (Musova et al., 2009). Genetic Heterogeneity of Myotonic DystrophySee also myotonic dystrophy-2 (DM2 ), which is caused by mutation in the ZNF9 gene (OMIM ) on chromosome 3q21.

MYOTONIC DYSTROPHY 1; DM1 Is also known as dystrophia myotonica 1|dystrophia myotonica|steinert disease|dm

• Intellectual disability
• Seizures
• Generalized hypotonia
• Muscle weakness
• Muscular hypotonia

SOURCES: OMIM MENDELIAN

3-methylglutaconic aciduria (3-MGA) type I is an inborn error of leucine metabolism with a variable clinical phenotype ranging from mildly delayed speech to psychomotor retardation, coma, failure to thrive, metabolic acidosis and dystonia.

3-METHYLGLUTACONIC ACIDURIA TYPE 1 Is also known as 3-methylglutaconyl-coa hydratase deficiency|3mg-coa hydratase deficiency|mga1|3-mg-coa-hydratase deficiency|mga, type i

• Seizures
• Global developmental delay
• Short stature
• Hearing impairment
• Microcephaly

SOURCES: OMIM ORPHANET MESH MENDELIAN

Distal Xq duplications refer to chromosomal disorders resulting from involvement of the long arm of the X chromosome (Xq). Clinical manifestations vary widely depending on the gender of the patient and on the gene content of the duplicated segment. The prevalence of Xq duplications remains unknown.

TRISOMY XQ28 Is also known as distal duplication xq|telomeric duplication xq

• Global developmental delay
• Short stature
• Cryptorchidism
• Ptosis
• Epicanthus

SOURCES: ORPHANET MENDELIAN

IECEE3 is an autosomal dominant neurologic disorder characterized by delayed psychomotor development, early-onset refractory seizures, and intellectual disability. The severity of the phenotype is highly variable: some patients may be nonverbal and nonambulatory with spastic quadriparesis and poor eye contact, whereas others have moderate intellectual disability (summary by Fassio et al., 2018).For a discussion of genetic heterogeneity of IECEE, see IECEE1 (OMIM ).

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Microcephaly

SOURCES: OMIM MENDELIAN