Generalized hypotonia, and Coarse facial features

X-linked mental retardation-19 (MRX19) is a nonsyndromic form of mild to moderate mental retardation. Carrier females may be mildly affected. Mutation in the RPS6KA3 gene also causes Coffin-Lowry syndrome (CLS ), a mental retardation syndrome with dysmorphic facial features and skeletal anomalies. Some patients with RPS6KA3 mutations have an intermediate phenotype with mental retardation and only mild anomalies reminiscent of CLS. These individuals have mutations resulting in some residual protein function, which likely explains the milder phenotype (summary by Field et al., 2006).

• Intellectual disability
• Short stature
• Generalized hypotonia
• Scoliosis
• Hypertelorism

SOURCES: OMIM MESH MENDELIAN

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

SOURCES: OMIM ORPHANET MENDELIAN

Nonsyndromic mental retardation. Hypotonia in infancy, poor or absent speech, and other disorders are occasionally associated.

MENTAL RETARDATION, X-LINKED 49; MRX49 Is also known as mental retardation, x-linked 15|mrx15

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

SOURCES: OMIM MENDELIAN

Sialic acid storage diseases are autosomal recessive neurodegenerative disorders that may present as a severe infantile form (ISSD) or as a slowly progressive adult form that is prevalent in Finland (Salla disease). The main symptoms are hypotonia, cerebellar ataxia, and mental retardation; visceromegaly and coarse features are also present in the infantile cases. Progressive cerebellar atrophy and dysmyelination have been documented by MRI. Enlarged lysosomes are seen on electron microscopic studies, and patients excrete large amounts of free sialic acid in the urine (Verheijen et al., 1999).

FREE SIALIC ACID STORAGE DISEASE, INFANTILE FORM Is also known as issd|sialuria, finnish type

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

SOURCES: ORPHANET OMIM MENDELIAN

Resistance to thyrotropin-releasing hormone (TRH) syndrome is a type of central congenital hypothyroidism (see this term) characterized by low levels of thyroid hormones due to insufficient release of thyroid-stimulating hormone (TSH) caused by pituitary resistance to TRH. It may or may not be observed from birth.

RESISTANCE TO THYROTROPIN-RELEASING HORMONE SYNDROME Is also known as trh resistance syndrome|central hypothyroidism due to trh receptor deficiency

• Global developmental delay
• Generalized hypotonia
• Growth delay
• Muscular hypotonia
• Feeding difficulties

SOURCES: ORPHANET MENDELIAN

• Intellectual disability
• Global developmental delay
• Short stature
• Generalized hypotonia
• Hearing impairment

SOURCES: OMIM MENDELIAN

Cortical dysplasia-focal epilepsy syndrome is a rare genetic epilepsy characterized by relatively large head circumference or macrocephaly, diminished or absent deep-tendon reflexes and mild gross motor delay in infancy, followed by intractable focal seizures with language regression, behavioral abnormalities (hyperactivity, attention deficit, aggressive/autoaggressive behavior, autistic features) and intellectual disability later in life.

CORTICAL DYSPLASIA-FOCAL EPILEPSY SYNDROME Is also known as cdfe syndrome|cortical dysplasia-focal epilepsy syndrome|cdfes

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

SOURCES: OMIM ORPHANET MENDELIAN

Spastic paraplegia-47 is an autosomal recessive neurodegenerative disorder characterized by neonatal hypotonia that progresses to hypertonia and spasticity and severe mental retardation with poor or absent speech development (summary by Abou Jamra et al., 2011).

SPASTIC PARAPLEGIA 47, AUTOSOMAL RECESSIVE; SPG47 Is also known as cpsq5, formerly|cerebral palsy, spastic quadriplegic, 5, formerly

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

SOURCES: OMIM MENDELIAN

Isolated thyroid-stimulating hormone (TSH) deficiency is a type of central congenital hypothyroidism (see this term), a permanent thyroid deficiency that is present from birth, characterized by low levels of thyroid hormones due to a deficiency in TSH synthesis.

ISOLATED THYROID-STIMULATING HORMONE DEFICIENCY Is also known as isolated thyrotropin deficiency|thyrotropin deficiency, isolated|pituitary cretinism|isolated tsh deficiency|tsh deficiency|thyroid-stimulating hormone deficiency

• Generalized hypotonia
• Muscular hypotonia
• Feeding difficulties
• Depressed nasal bridge
• Fatigue

SOURCES: ORPHANET OMIM MENDELIAN

Hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS) is a historical term used to describe a phenotype now considered to be part of the X-linked L1 clinical spectrum (L1 syndrome, see this term). HSAS is characterized by severe hydrocephalus mostly with prenatal onset, signs of intracranial hypertension, adducted thumbs, spasticity, and severe intellectual deficit. HSAS represents the severe end of the spectrum and is associated with poor prognosis.

HYDROCEPHALUS WITH STENOSIS OF THE AQUEDUCT OF SYLVIUS Is also known as x-linked hydrocephalus|hsas1|hycx|aqueductal stenosis, x-linked|bickers-adams syndrome|x-linked acqueductal stenosis|xlas|hydrocephalus, x-linked|x-linked hydrocephalus with stenosis of aqueduct of sylvius|x-linked hsas|hsas

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

SOURCES: OMIM ORPHANET MENDELIAN